Updated on 2021/04/02

写真a

 
YAMAZATO Takaya
 
Organization
Nagoya University Institute of Liberal Arts and Sciences Education Planning & Development Center Division of Developmnet Professor
Title
Professor

Degree 1

  1. Doctor of Engineering ( 1993.3   Keio University ) 

Research Interests 6

  1. e-Learning

  2. visible light communications

  3. vehicle-to-vehicle communications

  4. Stochastic Resonance

  5. Wireless sensor networks

  6. Visible light communications

Research Areas 2

  1. Others / Others  / Communication/Network Engineering

  2. Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Communication and network engineering

Current Research Project and SDGs 2

  1. Sensor Networks

  2. Visible Light Communications using LED array and high-speed camera

Research History 7

  1. Nagoya University   Nagoya University Library Studies   Professor

    2014.4

  2. Nagoya University   Administrative Support Organizations University Library Library Studies

    2014.4 - 2020.3

  3. Nagoya University

    2010.5

  4. Nagoya University

    2010.4

  5. Nagoya University   Institute of Liberal Arts and Sciences, Headquarters

    2007.4 - 2009.3

  6. Nagoya University   Re-organized Schools and Institutes / Centers Center for Information Media Studies   Center for Information Media Studies

    1998.4 - 2009.3

  7. Nagoya University   Graduate School of Engineering

    1997.4

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Education 3

  1. Keio University   Graduate School, Division of Science and Engineering   Department of electronics

    - 1993.3

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    Country: Japan

  2. Keio University   Graduate School of Science and Technology   Department of Electronics and Electrical Engineering

    1990.4 - 1993.3

  3. Shinshu University   Faculty of Engineering

    - 1988.3

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    Country: Japan

Professional Memberships 7

  1. The Institute of Electrical and Electronics Engineers (IEEE)   Director, Asia Pacific Board

    2016.1

  2. The Institute of Electronics, Information and Communication Engineers   Subleader, I-Scover Project

    2013.2

  3. The Institute of Electronics, Information and Communication Engineers   Vice chair, Technical Committee on ITS

    2012.6

  4. Japan Open CourseWare Consortium

  5. Japanese Society for Engineering Education

  6. The Institute of Electronics, Information and Communication Engineers   Editorial Advisory Committee

    2013.5 - 2016.6

  7. THE INSTITUTE OF IMAGE INFORMATION AND TELEVISION ENGINEERS

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Committee Memberships 1

  1. IEEE Communication Society   Asia Pacific Board Director  

    2016.1 - 2017.12   

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    Committee type:Academic society

Awards 6

  1. IEICE 2019 Best Paper Award

    2020.6   Institute of Electronics, Information and Communication Engineers (IEICE)   For the Applications of Stochastic Resonance in the Telecommunications

    Yukihiro TADOKORO, Takaya YAMAZATO, Hiroya TANAKA, Shintaro ARAI, Yasuo NAKASHIMA, Shintaro HIRAOKA

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    Award type:Honored in official journal of a scientific society, scientific journal  Country:Japan

  2. 電子情報通信学会 通信ソサイエティ 活動功労賞

    2008.9   電子情報通信学会  

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    Country:Japan

    研専運営会議総務幹事としての貢献

  3. IEEE Communication Society 2006 Best Tutorial Paper Award

    2006.6   The Institute of Electrical and Electronics Engineers (IEEE)  

  4. 電子情報通信学会 基礎・境界ソサイエティ 特別功労賞

    2005.9   (社)電子情報通信学会  

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    Country:Japan

    研究会発表申し込み Web システムの構築等研究会活動発展への貢献

  5. 電子情報通信学会 通信ソサイエティ 活動功労賞

    2005.9   (社)電子情報通信学会  

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    Country:Japan

  6. 電子情報通信学会 学術奨励賞

    1996  

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    Country:Japan

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Papers 1417

  1. Special section on intelligent transport systems Reviewed

    Saho K.

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   Vol. E104A ( 2 )   2021.2

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    Publishing type:Research paper (scientific journal)   Publisher:IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences  

    DOI: 10.1587/transfun.2020TSF0001

    Scopus

  2. Optical Wireless Communication: A Candidate 6G Technology? Reviewed

    Arai Shintaro, Kinoshita Masayuki, Yamazato Takaya

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   Vol. E104A ( 1 ) page: 227 - 234   2021.1

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    Publishing type:Research paper (scientific journal)   Publisher:一般社団法人 電子情報通信学会  

    <p>We discuss herein whether an optical wireless communication (OWC) system can be a candidate for post 5G or 6G cellular communication. Almost once per decade, cellular mobile communication is transformed by a significant evolution, with each generation developing a distinctive concept or technology. Interestingly, similar trends have occurred in OWC systems based on visible light and light fidelity (Li-Fi). Unfortunately, OWC is currently relegated to a limited role in any 5G scenario, but the debate whether this is unavoidable has yet to be settled. Whether OWC is adopted post 5G or 6G is not the vital issue; rather, the aim should be that OWC coexists with 5G and 6G communication technologies. In working toward this goal, research and development in OWC will continue to extend its benefits and standardize its systems so that it can be widely deployed in the market. For example, given that a standard already exists for a visible-light beacon identifier and Li-Fi, a service using this standard should be developed to satisfy user demand. Toward this end, we propose herein a method for visible-light beacon identification that involves using a rolling shutter to receive visible-light communications with a smartphone camera. In addition, we introduce a rotary LED transmitter for image-sensor communication.</p>

    DOI: 10.1587/transfun.2020WBI0001

    Web of Science

    Scopus

    CiNii Article

  3. Deep Learning Detection for superimposed control signal in LEO-MIMO Reviewed

    Okema R.

    2020 IEEE Global Communications Conference, GLOBECOM 2020 - Proceedings   Vol. 2020-January   2020.12

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    Publishing type:Research paper (scientific journal)   Publisher:2020 IEEE Global Communications Conference, GLOBECOM 2020 - Proceedings  

    DOI: 10.1109/GLOBECOM42002.2020.9348012

    Scopus

  4. Estimation for direction of signal arrival based on area density of estimated lines for ultrasonic sensor array Reviewed

    Morita E.

    2020 IEEE 9th Global Conference on Consumer Electronics, GCCE 2020     page: 333 - 335   2020.10

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    Publishing type:Research paper (scientific journal)   Publisher:2020 IEEE 9th Global Conference on Consumer Electronics, GCCE 2020  

    DOI: 10.1109/GCCE50665.2020.9291797

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  5. Nonlinear Transform for Parallel Transmission for Image-Sensor-based Visible Light Communication Reviewed

    Takahashi K.

    IEEE International Conference on Communications   Vol. 2020-June   2020.6

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    Publishing type:Research paper (scientific journal)   Publisher:IEEE International Conference on Communications  

    DOI: 10.1109/ICC40277.2020.9148927

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  6. Visible Light Communications for Automotive Intelligence Reviewed

    Yamazato T.

    2020 Optical Fiber Communications Conference and Exhibition, OFC 2020 - Proceedings     2020.3

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    Publishing type:Research paper (scientific journal)   Publisher:2020 Optical Fiber Communications Conference and Exhibition, OFC 2020 - Proceedings  

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  7. BER Measurement for Transmission Pattern Design of ITS Image Sensor Communication Using DMD Projector Reviewed

    Arisue T.

    2020 IEEE 17th Annual Consumer Communications and Networking Conference, CCNC 2020     2020.1

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    Publishing type:Research paper (scientific journal)   Publisher:2020 IEEE 17th Annual Consumer Communications and Networking Conference, CCNC 2020  

    DOI: 10.1109/CCNC46108.2020.9045147

    Scopus

  8. Nonlinear Transform for Parallel Transmission for Image-Sensor-based Visible Light Communication Reviewed

    Takahashi Kotomi, Kamakura Koji, Kinoshita Masayuki, Yamazato Takaya

    ICC 2020 - 2020 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC)     2020

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  9. Sequential maximum likelihood decoding incorporating reliability determination for image sensor communication Reviewed

    Tang Zhengqiang, Arai Shintaro, Yendo Tomohiro, He Di, Yamazato Takaya

    IEICE Communications Express   Vol. 9 ( 8 ) page: 365 - 370   2020

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    Publishing type:Research paper (scientific journal)   Publisher:一般社団法人 電子情報通信学会  

    <p>In this study, the sequential maximum likelihood decoding (S-MLD) for image sensor based visible light communication, referred to as image sensor communication, is proposed. The conventional system cannot correctly decode degraded captured images. To overcome this problem, S-MLD partitions the LED area on the image into two segments and sequentially creates pseudo-captured images, which imitate all possible LED blinking patterns. This approach is based on MLD for each segment. Moreover, reliability determination is incorporated to improve communication quality. We performed computer simulations and confirmed that S-MLD exhibits superior decoding performance and approximately 90% computational cost reduction compared to the previous MLD.</p>

    DOI: 10.1587/comex.2020XBL0058

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  10. Visible light communications for automotive intelligence Reviewed

    Yamazato T.

    Optics InfoBase Conference Papers   Vol. Part F174-OFC 2020   2020

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    Publishing type:Research paper (scientific journal)   Publisher:Optics InfoBase Conference Papers  

    DOI: 10.1364/OFC.2020.Th1K.1

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  11. Stereo ranging method using led transmitter for visible light communication Reviewed

    Kinoshita M.

    2019 IEEE Global Communications Conference, GLOBECOM 2019 - Proceedings     2019.12

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    Publishing type:Research paper (scientific journal)   Publisher:2019 IEEE Global Communications Conference, GLOBECOM 2019 - Proceedings  

    DOI: 10.1109/GLOBECOM38437.2019.9013641

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  12. Analysis of Data Collected by the 700 MHz Band Intelligent Transport Systems for Reducing Ambulance Transportation Time Reviewed

    Takuya Mitani, Takaya Yamazato, Katsuhiro Naito, Yuki Mori

    IEEE International Conference on Connected Vehicles and Expo:ICCVE 2019     2019.11

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    Language:English   Publishing type:Research paper (international conference proceedings)  

  13. Analysis of Data Collected by the 700 MHz Band Intelligent Transport Systems for Reducing Ambulance Transportation Time Reviewed

    Mitani T.

    2019 8th IEEE International Conference on Connected Vehicles and Expo, ICCVE 2019 - Proceedings     2019.11

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    Publishing type:Research paper (scientific journal)   Publisher:2019 8th IEEE International Conference on Connected Vehicles and Expo, ICCVE 2019 - Proceedings  

    DOI: 10.1109/ICCVE45908.2019.8965232

    Scopus

  14. Direct wireless link to out-of-range node with assistance of surrounding nodes Reviewed

    Hiroya Tanaka, Shintaro Hiraoka, Shintaro Arai, Takaya Yamazato, Yukihiro Tadokoro

    IEEE Transactions on Vehicular Technology   Vol. 68 ( 11 ) page: 10703 - 10712   2019.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/TVT.2019.2934502

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  15. Proposal for Identification Scheme of Driver and Impostor based on Acceleration Data Reviewed

    Yuki Mori, Ryota Ono, Takuya Mitani, Katsuhiro Naito, Takaya Yamazato

    IEEE International Conference on Connected Vehicles and Expo:ICCVE 2019     2019.11

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    Language:English   Publishing type:Research paper (international conference proceedings)  

  16. Proposal for identification scheme of driver and impostor based on acceleration data Reviewed

    Mori Y.

    2019 8th IEEE International Conference on Connected Vehicles and Expo, ICCVE 2019 - Proceedings     2019.11

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    Publishing type:Research paper (scientific journal)   Publisher:2019 8th IEEE International Conference on Connected Vehicles and Expo, ICCVE 2019 - Proceedings  

    DOI: 10.1109/ICCVE45908.2019.8965241

    Scopus

  17. Noise-aided demodulation of direct spread-code division multiple access signals with a 1bit analog-to-digital converter Reviewed

    Yasuo NAKASHIMA, Takaya YAMAZATO, Shintaro ARAI, Hiroya TANAKA, Yukihiro TADOKORO

    IEICE TRANSACTIONS on Communications   Vol. J102-B ( 8 )   2019.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.14923/transcomj.2018WFP0008

  18. High performance demodulation method with less complexity for image-sensor communication Reviewed

    Ohira Yuki, Yendo Tomohiro, Arai Shintaro, Yamazato Takaya

    OPTICS EXPRESS   Vol. 27 ( 15 ) page: 21565 - 21578   2019.7

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1364/OE.27.021565

    Web of Science

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  19. MD2.3-visible light communication and ranging system using high-speed stereo cameras (Invited) Reviewed

    Kinoshita M.

    IEEE Photonics Society Summer Topical Meeting Series 2019, SUM 2019     2019.7

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    Publishing type:Research paper (scientific journal)   Publisher:IEEE Photonics Society Summer Topical Meeting Series 2019, SUM 2019  

    DOI: 10.1109/PHOSST.2019.8794881

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  20. {For the applications of Stochastic resonance in the telecommunications Reviewed

    IEICE TRANSACTIONS on Communications   Vol. J102-B ( 6 ) page: 445 - 458   2019.6

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.14923/transcomj.2018JBR0001

  21. Parallel Transmission Using M-Point DFT for Image-Sensor-Based Visible Light Communication Reviewed

    Kibe S.

    2018 IEEE Globecom Workshops, GC Wkshps 2018 - Proceedings     2019.2

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    Publishing type:Research paper (scientific journal)   Publisher:2018 IEEE Globecom Workshops, GC Wkshps 2018 - Proceedings  

    DOI: 10.1109/GLOCOMW.2018.8644501

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  22. Performance Evaluation of Precoded Pulse Width Modulation for Image Sensor Communication Reviewed

    Kamegawa S.

    2018 IEEE Globecom Workshops, GC Wkshps 2018 - Proceedings     2019.2

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    Publishing type:Research paper (scientific journal)   Publisher:2018 IEEE Globecom Workshops, GC Wkshps 2018 - Proceedings  

    DOI: 10.1109/GLOCOMW.2018.8644347

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  23. Enhancing a BPSK receiver with Stochastic resonance by employing practical parallel arrayed network Reviewed

    Yukihiro Tadokoro, Hiroya Tanaka, Yasuo Nakashima, Takaya Yamazato, Shintaro Arai

    Nonlinear Theory and Its Applications, IEICE   Vol. 10 ( 1 ) page: 106 - 114   2019

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1587/nolta.10.106

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  24. Maximum Likelihood Decoding Based on Pseudo-Captured Image Templates for Image Sensor Communication Reviewed

    Shintaro ARAI, Haruna MATSUSHITA, Yuki OHIRA, Tomohiro YENDO, Di HE, Takaya YAMAZATO

    Nonlinear Theory and Its Applications, IEICE   Vol. 10 ( 2 ) page: 173 - 189   2019

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1587/nolta.10.173

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  25. Analysis of Data Collected by the 700 MHz Band Intelligent Transport Systems for Reducing Ambulance Transportation Time Reviewed

    Mitani Takuya, Yamazato Takaya, Naito Katsuhiro, Mori Yuki

    2019 8TH IEEE INTERNATIONAL CONFERENCE ON CONNECTED VEHICLES AND EXPO (IIEEE CCVE)     2019

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  26. Proposal for Identification Scheme of Driver and Impostor based on Acceleration Data Reviewed

    Mori Yuki, Ono Ryota, Mitani Takuya, Naito Katsuhiro, Yamazato Takaya

    2019 8TH IEEE INTERNATIONAL CONFERENCE ON CONNECTED VEHICLES AND EXPO (IIEEE CCVE)     2019

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  27. Noise-aided demodulation with one-bit comparator for multilevel pulse-amplitude-modulated signals Reviewed

    Yasuo Nakashima, Takaya Yamazato, Shintaro Arai, Hiroya Tanaka, Yukihiro Tadokoro

    IEEE Wireless Communication Letters   Vol. 7 ( 5 ) page: 848 - 851   2018.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/LWC.2018.2831683

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    Scopus

  28. Technical Issues on IEEE 802.15.7m Image Sensor Communication Standardization Reviewed

    Trang Nguyen, Amirul Islam, Takaya Yamazato, Yeong Min Jang

    IEEE Communications Magazine   Vol. 56 ( 2 ) page: 213 - 218   2018.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Institute of Electrical and Electronics Engineers Inc.  

    This tutorial article presents an outline of image sensor communication (ISC) technologies realized by light sources and cameras. It discusses the revision of the IEEE 802.15.7-2011 standard, namely, the IEEE 802.15.7m Optical Wireless Communications Task Group, which has significantly influenced the development of the ISC technology. It also reviews the ISC technical proposals of the task group and compares them with related works. The essential technical considerations of the ISC specifications are presented, and the future directions of research and development are discussed.

    DOI: 10.1109/MCOM.2018.1700134

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    Scopus

  29. N-Stream Superimposed System with m-Point DFT for Image-Sensor-Based Visible Light Communication Reviewed

    Syuto Kibe, Koji Kamakura, Takaya Yamazato

    2017 IEEE Global Communications Conference, GLOBECOM 2017 - Proceedings   Vol. 2018-   page: 1 - 6   2018.1

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Institute of Electrical and Electronics Engineers Inc.  

    This paper proposes an N-stream superimposed system for image-sensor-based visible light communications (ISbased VLC). Based on the principle of m-point discrete Fourier transform (DFT), a phase shift keying (PSK) signal is transmitted over m consecutive time slots mT, where T is a slot duration. In practice, the symbol rate of this paper is R/(m + 1) because a guard slot is inserted every m slots. In the superimposed system, N data streams where the symbol rate of the nth data stream, n = {1, 2,.., N}, is 1/(m+ 1)n-1 times the symbol rate of the first data stream are combined to form a pulse-width modulated (PWM) wave with a period time T. An IS receiver with a camera operating at a frame rate of R/(m+ 1)n-1 fps demodulates data streams whose symbol rate is R/m+ 1)n symbol/s or lower. Our experimental results validate that from a superimposed PWM wave of 500-symbol/s and 125-symbol/s data streams, a 2000-fps camera receiver demodulates both of the two data streams and the 500-fps camera receiver does the 125-symbol/s data stream successfully, without shortening individual error-free transmission ranges, compared with non-superimposed systems in which 500-symbol/s and 125-symbol/s data streams are independently transmitted by different light emitting diode (LED) transmitters and received by 2000-fps and 500-fps camera receivers, respectively.

    DOI: 10.1109/GLOCOM.2017.8254784

    Scopus

  30. Practical Applications of Visible Light Communications Invited

    T. Yamazato, H. Okada

    Journal of IEICE   Vol. 101 ( 1 ) page: 59-65   2018.1

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

  31. Simplified Vehicle Vibration Modeling for Image Sensor Communication Reviewed

    KINOSHITA Masayuki, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, ARAI Shintaro, YENDO Tomohiro, KAMAKURA Koji

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   Vol. 101 ( 1 ) page: 176-184   2018

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1587/transfun.E101.A.176

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  32. Interference-Aided Detection of Subthreshold Signal Using Beam Control in Polarization Diversity Reception. Reviewed

    Shintaro Hiraoka, Yasuo Nakashima, Takaya Yamazato, Shintaro Arai, Yukihiro Tadokoro, Hiroya Tanaka

    IEEE Communications Letters   Vol. 22 ( 9 ) page: 1926 - 1929   2018

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/LCOMM.2018.2851583

    Web of Science

    Scopus

  33. A Comparison of Reception Methods for Visible Light Communication Using High-speed Stereo Cameras Reviewed

    Kinoshita Masayuki, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Arai Shintaro, Yendo Tomohiro, Kamakura Koji

    2018 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM)     page: .   2018

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    Language:English  

    Web of Science

  34. Performance Evaluation of Precoded Pulse Width Modulation for Image Sensor Communication Reviewed

    Kamegawa Satoshi, Kinoshita Masayuki, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Kamakura Koji, Yendo Tomohiro, Arai Shintaro

    2018 IEEE GLOBECOM WORKSHOPS (GC WKSHPS)     page: .   2018

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    Language:English  

    Web of Science

  35. Parallel Transmission Using M-point DFT for Image-Sensor-Based Visible Light Communication Reviewed

    Kibe Syuto, Kamakura Koji, Yamazato Takaya

    2018 IEEE GLOBECOM WORKSHOPS (GC WKSHPS)     page: .   2018

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    Language:English  

    Web of Science

  36. Noise-aided demodulation with one-bit ADC for quadrature amplitude modulated signals Reviewed

    Nakashima Yasuo, Yamazato Takaya, Arai Shintaro, Tanaka Hiroya, Tadokoro Yukihiro

    2018 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM)     page: .   2018

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    Web of Science

  37. LEO-MIMO Satellite Systems for High Capacity Transmission Reviewed

    Goto Daisuke, Shibayama Hiroki, Yamashita Fumihiro, Yamazato Takaya

    2018 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM)     page: .   2018

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    Web of Science

  38. A Comparison of Reception Methods for Visible Light Communication Using High-Speed Stereo Cameras Reviewed

    Kinoshita M.

    2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings     2018

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    Publishing type:Research paper (scientific journal)   Publisher:2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings  

    DOI: 10.1109/GLOCOM.2018.8647953

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  39. Image sensor communications for future ITS Reviewed

    Yamazato T.

    Optics InfoBase Conference Papers   Vol. Part F112-SPPCom 2018   2018

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    Publishing type:Research paper (scientific journal)   Publisher:Optics InfoBase Conference Papers  

    DOI: 10.1364/SPPCom.2018.SpW2G.6

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  40. LEO-MIMO Satellite Systems for High Capacity Transmission Reviewed

    Goto D.

    2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings     2018

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    Publishing type:Research paper (scientific journal)   Publisher:2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings  

    DOI: 10.1109/GLOCOM.2018.8647694

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  41. Noise-Aided Demodulation with One-Bit ADC for Quadrature Amplitude Modulated Signals Reviewed

    Nakashima Y.

    2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings     2018

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    Publishing type:Research paper (scientific journal)   Publisher:2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings  

    DOI: 10.1109/GLOCOM.2018.8648114

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  42. Modulation and coding for image sensor communication Reviewed

    Koji Kamakura, Takaya Yamazato

    30th Annual Conference of the IEEE Photonics Society, IPC 2017   Vol. 2017-   page: 235 - 236   2017.11

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Institute of Electrical and Electronics Engineers Inc.  

    Most practical visible light communication (VLC) systems being currently deployed with image sensor receivers use intensity modulation and direct detection scheme for outdoor and indoor applications. A number of modulation and coding techniques that are used for image sensor-based VLC systems are presented.

    DOI: 10.1109/IPCon.2017.8116086

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  43. The Uplink Visible Light Communication Beacon System for Universal Traffic Management Reviewed

    Takaya Yamazato ; Naoaki Kawagita ; Hiraku Okada ; Toshiaki Fujii ; Tomohiro Yendo ; Shintaro Arai ; Koji Kamakura

    IEEE Access   ( 5 ) page: 22282 - 22290   2017.10

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    This paper presents a feasibility study of the uplink visible light communication (VLC) beacon system for the universal traffic management system (UTMS). The UTMS is a traffic management system beneath the National Police Agency of Japan. Currently, 55 000 UTMS infrared beacon systems have been installed, and they provide expressway and ordinary road information to cars. However, the data rate is 1 Mbps, and a faster data rate is necessary to support automotive and smart mobility devices. In this paper, we propose an uplink V2I system for the UTMS. The system is designed to match the current beacon system as closely as possible, so that the system can easily be replaced and still provide sufficient bandwidth for future automotive and smart mobility devices. We adopt a photo diode (PD) as the VLC receiver and a commercially available off-the-shelf LED headlight as a transmitter. Unfortunately, the bandwidth of such an LED is usually small, so we consider applying a bit-loading algorithm to direct-current-biased optical orthogonal frequency division multiplexing. To reduce strong background noise, such as from the sun, we narrow down the field-of-view by applying a lens to the PD, which forms a tiny communication area, smaller than the current infrared beacon system. We then consider multiple PDs with the lens to create a similar communication area as the infrared beacon system. As a result, we achieve 3.1-Mbps throughput.

    DOI: 10.1109/ACCESS.2017.2759179

  44. Modeling and parameter estimation of vehicle vibration inducing transmitter displacement in ITS image sensor communication Reviewed

    Masayuki Kinoshita, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Shintaro Arai, Tomohiro Yendo, Koji Kamakura

    2017 IEEE International Conference on Communications Workshops, ICC Workshops 2017     page: 144 - 149   2017.6

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Institute of Electrical and Electronics Engineers Inc.  

    Image sensor communication (ISC), which is derived from visible light communication (VLC), is a novel form of wireless communication that uses an image sensor as a receiver. ISC is an attractive solution for outdoor mobile environments and is particularly well-suited to intelligent transport systems (ITS). The purpose of this paper is to derive the dominant components of vehicle vibrations and road surface irregularities that induce transmitter displacement in ITS-ICS in paved road scenarios. Such displacements make it difficult for a ISC receiver to select the correct pixels. We measured vehicle vibrations during an actual driving scenario using a six-axis acceleration sensor installed in a smartphone. Using the results obtained, we performed a frequency analysis of the vehicle vibrations and determined the parameters of vehicle vibrations based on the frequency characteristics. This paper explains that the vehicle vibrations that affect the communication performance can be modeled by solely using Gaussian random processes when a high frame rate (e.g. 1000 fps) image sensor is used as the ISC receiver.

    DOI: 10.1109/ICCW.2017.7962648

    Scopus

  45. Global Communications Newsletter. Reviewed

    Stefano Bregni, Takaya Yamazato, Vasile Bota,Liangping Ma

    IEEE Communications Magazine   Vol. 55 ( 2 ) page: 13 - 16   2017

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    Language:English   Publishing type:Research paper (scientific journal)  

    Asia/Pacific Region
    Interview with Takaya Yamazato, Director of the AP Region
    This is the fourth article in the series of eight, started in November 2016 and published monthly in the IEEE ComSoc Global Communications Newsletter, which covers all areas of IEEE ComSoc Member and Global Activities. In this series of articles, I am introducing the six MGA Directors (Sister and Related Societies; Membership Services; AP, NA, LA, EMEA Regions) and the two Chairs of the Women in Communications Engineering (WICE) and Young Professionals (YP) Standing Committees. In each article, one by one they present their sector activities and plans.

    In this issue, I interview Takaya Yamazato, Director of the Asia/Pacific Region (AP). Takaya is a professor at the Institute of Liberal Arts and Sciences, Nagoya University, Japan. He received the Ph.D. degree from Keio University, Yokohama, Japan, in 1993. From 1993 to 1998 he was an assistant professor in the Department of Information Electronics, Nagoya University, Japan. From 1997 to 1998 he was a visiting researcher in the Research Group for RF Communications, Department of Electrical Engineering and Information Technology, University of Kaiserslautern, Germany. In 2006 he received the IEEE Communication Society Best Tutorial Paper Award. He served as symposium co-chair of ICC 2009 and ICC 2011. From 2008 to 2010 he was the chair of the IEEE ComSoc Satellite and Space Communications Technical Committee and the editor-in-chief of the Japanese Section of IEICE Transactions on Communications. His research interests include visible light communication, intelligent transport systems, stochastic resonance, and open educational resources.

    DOI: 10.1109/MCOM.2017.7841463

  46. Effect of a root-raised-cosine filter on a BPSK stochastic resonance receiver

    Nakashima Yasuo, Tanaka Hiroya, Yamazato Takaya, Tadokoro Yukihiro, Arai Shintaro

    IEICE NONLINEAR THEORY AND ITS APPLICATIONS   Vol. 8 ( 3 ) page: 204-214   2017

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    DOI: 10.1587/nolta.8.204

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  47. Effect of a root-raised-cosine filter on a BPSK stochastic resonance receiver Reviewed

    Nakashima Yasuo, Tanaka Hiroya, Yamazato Takaya, Tadokoro Yukihiro, Arai Shintaro

    IEICE NONLINEAR THEORY AND ITS APPLICATIONS   Vol. 8 ( 3 ) page: 204-214   2017

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    DOI: 10.1587/nolta.8.204

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  48. Overview of Visible Light Communications - With Emphasis on Image Sensor Communications -

    Yamazato Takaya

    2017 23RD ASIA-PACIFIC CONFERENCE ON COMMUNICATIONS (APCC): BRIDGING THE METROPOLITAN AND THE REMOTE     page: 564-569   2017

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  49. N-Stream Superimposed System with m-point DFT for Image-Sensor-Based Visible Light Communication

    Kibe Syuto, Kamakura Koji, Yamazato Takaya

    GLOBECOM 2017 - 2017 IEEE GLOBAL COMMUNICATIONS CONFERENCE     page: .   2017

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  50. Modulation and Coding For Image Sensor Communication

    Kamakura Koji, Yamazato Takaya

    30TH ANNUAL CONFERENCE OF THE IEEE PHOTONICS SOCIETY (IPC)     page: 235-236   2017

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  51. Overview of visible light communications with emphasis on image sensor communications. Reviewed

    Takaya Yamazato

    23rd Asia-Pacific Conference on Communications, APCC 2017, Perth, Australia, December 11-13, 2017   Vol. 2018-January   page: 1 - 6   2017

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    DOI: 10.23919/APCC.2017.8304093

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  52. V2X communications with an image sensor. Reviewed

    Takaya Yamazato

    J. Comm. Inform. Networks   Vol. 2 ( 4 ) page: 65 - 74   2017

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    DOI: 10.1007/s41650-017-0044-4

  53. A New Automotive VLC System Using Optical Communication Image Sensor Reviewed

    Yuki Goto, Isamu Takai, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Shoji Kawahito, Shintaro Arai, Tomohiro Yendo, Koji Kamakura

    IEEE PHOTONICS JOURNAL   Vol. 8 ( 3 )   2016.6

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    As a new technology for next-generation vehicle-to-everything (V2X) communication, visible-light communication (VLC) using light-emitting diode (LED) transmitters and camera receivers has been energetically studied. Toward the future in which vehicles are connected anytime and anywhere by optical signals, the cutting-edge camera receiver employing a special CMOS image sensor, i.e., the optical communication image sensor (OCI), has been prototyped, and an optical V2V communication system applying this OCI-based camera receiver has already demonstrated 10-Mb/s optical signal transmission between real vehicles during outside driving. In this paper, to reach a transmission performance of 54 Mb/s, which is standardized as the maximum data rate in IEEE 802.11p for V2X communication, a more advanced OCI-based automotive VLC system is described. By introducing optical orthogonal frequency-division multiplexing (optical-OFDM), the new system achieves a more than fivefold higher data rate. Additionally, the frequency response characteristics and circuit noise of the OCI are closely analyzed and taken into account in the signal design. Furthermore, the forward-current limitation of an actual LED is also considered for long operational reliability, i.e., the LED is not operated in overdrive. Bit-error-rate experiments verify a system performance of 45 Mb/s without bit errors and 55 Mb/s with BER &lt; 10(-5).

    DOI: 10.1109/JPHOT.2016.2555582

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  54. A-14-8 Preliminary Study of Platoon Management using 700MHz Band Vehicle-to-Infrastructure Cooperative System Reviewed

    OHNO Ryota, YAMAZATO Takaya

    Proceedings of the IEICE Engineering Sciences Society/NOLTA Society Conference   Vol. 2016   2016.3

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  55. A-9-17 BER Performance of NLOS Vehicle to Vehicle Visible Light Communication Using Optical OFDM Reviewed

    KAWAGITA Naoaki, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, ARAI Shintaro, YENDO Tomohiro, KAMAKURA Koji

    Proceedings of the IEICE Engineering Sciences Society/NOLTA Society Conference   Vol. 2016   2016.3

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  56. AS-3-10 High Speed Image Sensor Based I2V-VLC Channel Modeling in Outdoor Mobile Environment Reviewed

    KINOSHTTA Masayuki, YAMAZATO Takaya, OKADA Hiraku, FUJII Yoshiaki, ARAI Shintaro, Yendo Tomohiro, KAMAKURA Koji

    Proceedings of the IEICE Engineering Sciences Society/NOLTA Society Conference   Vol. 2016   page: "S - 53"-"S-54"   2016.3

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  57. BI-4-3 ITS Visible Light Communications using High-Speed Image Sensor Reviewed

    Yamazato Takaya

    Proceedings of the IEICE General Conference   Vol. 2016 ( 1 ) page: "SS - 71"-"SS-72"   2016.3

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  58. BI-4-3 ITS Visible Light Communications using High-Speed Image Sensor Reviewed

    Yamazato Takaya

    Proceedings of the IEICE General Conference   Vol. 2016 ( 2 ) page: "SS - 83"-"SS-84"   2016.3

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  59. N-2-2 Performance Evaluation of Stochastic Resonance Receiver in Bandlimited BPSK Modulations Reviewed

    Nakashima Yasuo, TANAKA Hiroya, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the IEICE Engineering Sciences Society/NOLTA Society Conference   Vol. 2016   2016.3

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  60. NBS-1-1 Performance Improvement of Stochastic Resonance Receiver by Uniform Noise and Binary Noise Reviewed

    TANAKA Hiroya, NAKASHIMA Yasuo, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the IEICE Engineering Sciences Society/NOLTA Society Conference   Vol. 2016   page: "S - 113"-"S-114"   2016.3

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  61. NBS-1-1 Performance Improvement of Stochastic Resonance Receiver by Uniform Noise and Binary Noise Reviewed

    TANAKA Hiroya, NAKASHIMA Yasuo, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the IEICE General Conference   Vol. 2016 ( 2 ) page: "S - 133"-"S-134"   2016.3

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  62. Range Estimation Scheme for Integrated I2V-VLC using a High-Speed Image Sensor Reviewed

    T. Yamazato, A. Ohmura, H. Okada, T. Fujii, T. Yendo, S. Arai, K. Kamakura

    2016 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC)     page: 326 - 330   2016

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    High-speed image sensors, designed for machine vision and control, provide the "eyes" for autonomous and connected vehicle. A noteworthy feature of high-speed image sensors is their ability to be used as a reception device for visible light communication (VLC) signals. Due to the massive number of pixels available and the ability to spatially separate sources, a signal-receiving pixel in the image sensor plane represents the actual position of the transmitter. The VLC signal can be represented not only by a VLC time domain signal but also by the position of the transmitter. In this paper, we propose a robust range estimation scheme that integrates with a VLC function for infrastructure-to-vehicle visible light communication (I2V-VLC). The scheme is composed of an LED array transmitter and a high-speed image sensor receiver. It measures a range by taking phase-only correlation (POC) and avoids vehicle vibration from road irregularity. Field trials confirm an accuracy range of 0.3 m, even on rough road conditions, with the measurement time of 2 ms, which is much faster than that of light detection and ranging (LIDAR).

    DOI: 10.1109/ICCW.2016.7503808

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  63. Visible Light Communication Systems Using Blue Color Difference Modulation for Digital Signage Reviewed

    Sho Sato, Hiraku Okada, Kentaro Kobayashi, Takaya Yamazato, Masaaki Katayama

    2016 IEEE 27TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC)     page: 1219 - 1224   2016

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    Digital signage, which is advertising media using a liquid crystal display (LCD), is increasing in popularity. One possible application is wireless communications between digital signage and viewers. We focus on image-sensor-based visible light communication (VLC). Image-sensor-based VLC requires only an image sensor (IS), which is common equipment in smart phones. In the proposed method, an information signal is displayed on LCD. However, embedding the information signal into an advertisement may decrease the quality. We propose blue color difference modulation to make such signals imperceptible. We implemented a VLC system between digital signage and IS to demonstrate, the effectiveness of the proposed modulation in a real environment.

    DOI: 10.1109/PIMRC.2016.7794761

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  64. Position Estimation of LED Matrix in Image Sensor Communication Reviewed

    Takazumi Asai, Tomohiro Yendo, Shintaro Arai, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Koji Kamakura

    2016 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA)     page: 1 - 5   2016

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    We focus on the road-to-vehicle visible light communication (VLC) that system is composed of a LED matrix as a transmitter and a high-speed camera as a receiver. In this VLC system, intensity of each LED cannot be determined from received image directly in case that the receiver is distant from the transmitter. In previous research, a method to estimate intensity of the LED from received image is proposed. In this method, intensity of LED is estimated by using Moore-Penrose pseudo-inverse matrix of coefficient matrix, which expresses relation between intensity of LEDs and pixel values. However, the coefficient matrix changes every moment because it is determined by positional relation between the receiver and the LED traffic light in VLC system. In this paper, we propose a method to estimate position of the LED matrix using simulated images. We measure sensitivity distribution of image sensor to generate simulated images. We evaluated degree of similarity between simulated images and real images.

    DOI: 10.1109/APSIPA.2016.7820809

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  65. Spatial Modulation in Layered Space-Time Coding for Image-Sensor-Based Visible Light Communication Reviewed

    Keisuke Masuda, Koji Kamakura, Takaya Yamazato

    2016 IEEE 27TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC)     page: 1231 - 1236   2016

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    Spatial modulation (SM) is introduced into layered space-time coding (L-STC) used in image sensor (IS)-based visible light communication (VLC) systems. STC was basically investigated for extending the communication range of the IS-based VLC link [1], although it is out of the range when IS receivers are at the long distance from the LED array of the transmitter where the number of pixels capturing the transmitter on the image plane is less than the number of LEDs of the array. Furthermore, L-STC was done in [2] for increasing the reception rate with improving the pixel resolution while the receiver was approaching the transmitter. In this paper, SM is combined into L-STC by mapping additional information bits on the location of the pair of STC bit matrices of each layer. Experimental results show that additional SM bits are extracted with no error, without deteriorating the reception quality of and shrinking the transmission range of the original L-STC.

    DOI: 10.1109/PIMRC.2016.7794763

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  66. Performance comparison of stochastic resonance receiver with Schmitt trigger, comparator, and three-level device for subthreshold signal reception Reviewed

    Hiroya Tanaka, Takaya Yamazato, Yukihiro Tadokoro, Shintaro Arai

    Nonlinear Theory and Its Applications, IEICE   Vol. 7 ( 3 ) page: 407 - 418   2016

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    DOI: 10.1587/nolta.7.407

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  67. Position Estimation of LED Matrix in Image Sensor Communication Reviewed

    Asai Takazumi, Yendo Tomohiro, Arai Shintaro, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Kamakura Koji

    2016 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA)     2016

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  68. Spatial Modulation in Layered Space-Time Coding for Image-Sensor-Based Visible Light Communication Reviewed

    Masuda Keisuke, Kamakura Koji, Yamazato Takaya

    2016 IEEE 27TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC)     page: 1231 - 1236   2016

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  69. Transmit diversity with single RF front-end using CIOD Reviewed

    Yamaoka Tomoya, Hara Teruyuki, Okazaki Akihiro, Yamazato Takaya

    IEICE COMMUNICATIONS EXPRESS   Vol. 5 ( 2 ) page: 44 - 48   2016

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    Complex interleaved orthogonal design (CIOD) can offers diversity gain to the part of the source in spatial modulation which has single radio frequency (RF) front-end at the transmitter despite multiple-input multiple-output, but emits the undesired component out-of-band. For the reducing out-of-band emission, we give up indicating the information source by the antenna switching and increase both the interleaver size and the antenna switching interval. The increase reduces the discontinuities in the waveform and out-of-band emission. We propose such a scheme as transmit diversity with single RF front-end using CIOD. The diversity gain of the proposed scheme is equivalent to the case for CIOD. Moreover, we evaluate the increase of out-of-band emission and confirm that of the proposed scheme compared to the ideal case is only 3 dB.

    DOI: 10.1587/comex.2015XBL0170

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  70. Visible Light Communication Systems Using Blue Color Difference Modulation for Digital Signage Reviewed

    Sato Sho, Okada Hiraku, Kobayashi Kentaro, Yamazato Takaya, Katayama Masaaki

    2016 IEEE 27TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC)     page: 1219 - 1224   2016

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  71. LED acquisition methods for image-sensor-based visible light communication Reviewed

    Shintaro Arai; Takaya Yamazato; Hiraku Okada; Toshiaki Fujii; Tomohiro Yendo

    2015 Opto-Electronics and Communications Conference (OECC)     page: 1 - 3   2015.11

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    This invited paper focuses on a high-speed image sensor as a visible light communication (VLC) reception device to develop the intelligent transport systems (ITS) application using VLC technique. We refer to the VLC using a high-speed image sensor as image-sensor-based VLC. A major advantage of the image sensor is the ability to spatially separate multiple sources. Based on this ability, we proposed several methods for the image-sensor-based VLC in our previous researches. Especially, we focused on unique characteristics of the image sensor and proposed the hierarchical coding and the overlay coding to improve the data reception performance. However, to perform the image-sensor-based VLC in an actual environment, the receiver has to acquire the VLC transmitter from captured images before recovering data. Namely, the VLC transmitter acquisition and tracking are critical problem. the image-sensor-based VLC technique. This invited paper introduces two proposed methods to acquire the VLC transmitter from images captured by the image sensor.

    DOI: 10.1109/OECC.2015.7340210

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  72. Layered Transmission of Space-Time Coded Signals for Image-Sensor-Based Visible Light Communications Reviewed

    Katsunori Ebihara, Koji Kamakura, Takaya Yamazato

    JOURNAL OF LIGHTWAVE TECHNOLOGY   Vol. 33 ( 20 ) page: 4193 - 4206   2015.10

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    This paper demonstrates the feasibility of layered space-time coding (STC) in an outdoor image-sensor-based (IS-based) visible light communication (VLC) system. We examined that for low-resolution IS-based VLC channel where intensity-modulated signals from two different light emitting diodes (LEDs) are detected by one pixel of an IS, STC allows us to decouple them; thus, succeeding to receive them with no errors. Consequently, STC offers extended transmission distance to pixel-resolution-limited IS-based VLC links. In the layered STC presented in this paper, additional bit streams are laid on the 2(n) x 2(n) LED array for increasing the transmission rate per symbol duration for the case where the pixel resolution is improved. A prototype of a three-layered STC is built with an 8 x 8 LED array, where each of the LEDs is modulated at 1 kb/s and a high-speed camera with IS operating at 1000 fps. Our experimental results validate that the two additional bit streams (layer-2 and -3), aligned in the layer-1 STC matrix pair, are extracted with no errors when the receiver comes within 155 and 55 m, respectively, from the LED array, without decreasing 210 m of the transmission distance of layer-1 bit stream.

    DOI: 10.1109/JLT.2015.2470091

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  73. Image sensor based visible light communication for V2X Reviewed

    Takaya Yamazato

    2015 IEEE Summer Topicals Meeting Series (SUM)     page: 165 - 166   2015.9

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    The concepts of vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communications technologies using visible light communications (V2X-VLC) are introduced. Advantages of image sensor as a VLC receiver will be presented along with two important our findings.

    DOI: 10.1109/PHOSST.2015.7248248

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  74. Signal Demodulation Method from Degraded Image for Visible Light Communication Using LED and High-Speed Camera Reviewed

    Y. Ohira, S. Arai, T. Yendo, T. Yamazato, H. Okada, T. Fujii, K. Kamakura

    IEICE Transactions on Communications   Vol. J98-B ( 7 ) page: 696-706   2015.7

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  75. IEICE technical committees' contribution to I-scover keyword metadata improvements and selecting effective article keywords Reviewed

    Yamazato T.

    Journal of the Institute of Electronics, Information and Communication Engineers   Vol. 98 ( 6 ) page: 494 - 499   2015.6

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  76. Vehicle Motion and Pixel Illumination Modeling for Image Sensor Based Visible Light Communication Reviewed

    Takaya Yamazato; Masayuki Kinoshita; Shintaro Arai; Eisho Souke; Tomohiro Yendo; Toshiaki Fujii; Koji Kamakura; Hiraku Okada

    IEEE Journal on Selected Areas in Communications   Vol. 33 ( 9 ) page: 1793 - 1805   2015.5

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    Channel modeling is critical for the design and performance evaluation of visible light communication (VLC). Although a considerable amount of research has focused on indoor VLC systems using single-element photodiodes, there remains a need for channel modeling of VLC systems for outdoor mobile environments. In this paper, we describe and provide results for modeling image sensor based VLC for automotive applications. In particular, we examine the channel model for mobile movements in the image plane as well as channel decay according to the distance between the transmitter and the receiver. Optical flow measurements were conducted for three VLC situations for automotive use: infrastructure to vehicle VLC (I2V-VLC); vehicle to infrastructure VLC (V2I-VLC); and vehicle to vehicle VLC (V2V-VLC). We describe vehicle motion by optical flow with subpixel accuracy using phase-only correlation (POC) analysis and show that a single-pinhole camera model successfully describes these three VLC cases. In addition, the luminance of the central pixel from the projected LED area versus the distance between the LED and the camera was measured. Our key findings are twofold. First, a single-pinhole camera model can be applied to vehicle motion modeling of a I2V-VLC, V2I-VLC, and V2V-VLC. Second, the DC gain at a pixel remains constant as long as the projected image of the transmitter LED occupies several pixels. In other words, if we choose a pixel with highest luminance among the projected image of transmitter LED, the value remains constant, and the signal-to-noise ratio does not change according to the distance.

    DOI: 10.1109/JSAC.2015.2432511

  77. Detection method of the LED headlight and LED headlight identification method considering occlusion for V2I-VLC Reviewed

    KAWAI Yuta, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro, KAMAKURA Koji

      Vol. 114 ( 508 ) page: 23 - 28   2015.3

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    In this paper, we focus on the image sensor based vehicle-to-infrastructure visible light communication (V2I-VLC) for Intelligent Transport System (ITS). In this communication system, individual detection and tracking of multiple transmitters is critical. In other words, it is identification of the LED headlight between the frames. However, when occlusion occurs due to vehicle's movement, it becomes NLOS. I have the problem that it comes to have difficulty in identification of LED headlight then. Therefore, in this paper, we propose LED identification method that predict the position of the LED headlight on the image sensor when occlusion occurs. I install a high-speed camera in the roadside and test it and evaluate proposal technique. As a result, false negative rate is 1.38%,false positive rate is 3.26%. I confirmed that I could perform LED identification even if occlusion occurred.

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  78. Alamouti-Type Space Time Coding for Visible Light Communication Based on Direct Detection Using Image Sensor Reviewed

    Y. Amano, K. Kamakura, T. Yamazato

    IEICE Transactions on Communications   Vol. J98-B ( 3 ) page: 307-318   2015.3

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    This paper proposes Alamouti-type space time (ST) coding to visible light communication (VLC) using light emitting diodes (LEDs) and image sensor-based direct detection with a high-speed camera. Although multiple LEDs of an array are used as transmitters to communicate to individual pixel elements of an image sensor which act as multiple receive elements, the received signal is essentially the image of the transmitting element, whose size in pixel reduces with distance. When the receiver captures the LED array at a distance where images of two neighboring LEDs in the array are not separated at the image plane, such distortion depreciates the symbol decision quality. Our proposed scheme aims at expanding the communication range limited by the pixel resolution of image sensor. Our implemented prototype demonstrates that ST coding is feasible to achieve 48-meter error-free transmission range while the repetition transmission achieves 26-meter error-free range.

  79. Preliminary Study on NLOS V2V Visible Light Communication Using Retroreflective Traffic Control Devices

    T. Takada, T. Yamazato, H. Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura

    IEICE General Conference   Vol. A-17-16   page: 249   2015.3

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  80. Detection method of the LED headlight and LED headlight identification method considering occlusion for V2I-VLC

    Y. Kawai,T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai, K. Kamakura

    IEICE Technical Report   Vol. ITS2014-62   page: 23-28   2015.3

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    In this paper, we focus on the image sensor based vehicle-to-infrastructure visible light communication (V2I-VLC) for Intelligent Transport System (ITS). In this communication system, individual detection and tracking of multiple transmitters is critical. In other words, it is identification of the LED headlight between the frames. However, when occlusion occurs due to vehicle's movement, it becomes NLOS. I have the problem that it comes to have difficulty in identification of LED headlight then. Therefore, in this paper, we propose LED identification method that predict the position of the LED headlight on the image sensor when occlusion occurs. I install a high-speed camera in the roadside and test it and evaluate proposal technique. As a result, false negative rate is 1.38%,false positive rate is 3.26%. I confirmed that I could perform LED identification even if occlusion occurred.

  81. A-17-16 Preliminary Study on NLOS V2V Visible Light Communication Using Retroreflective Traffic Control Devices Reviewed

    TAKADA Takuma, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, ARAI Shintaro, YENDO Tomohiro, KAMAKURA Koji

    Proceedings of the IEICE General Conference   Vol. 2015   2015.2

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  82. A-2-18 Performance Evaluation of Stochastic Resonance Receiver in BPSK and OOK Modulations Reviewed

    TANAKA Hiroya, CHIGA Keita, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the IEICE General Conference   Vol. 2015   2015.2

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  83. Investigation on Relationship Between Communication Distance and Receiving Characteristics in Image-Sensor-Based Visible Light Communication Reviewed

    Y. Ohira, E. Souke, S. Arai, T. Yamazato, T. Yendo, H. Okada, T. Fujii and K. Kamakura

    Proceedings of 2015 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP'15)     page: 274-277   2015.2

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    The present paper considers receiving characteristics of an image-sensor-based visible light communication (VLC) using an LED and a high-speed-image sensor. In general, a size of LED on an image decreases with increasing a communication distance. In this case, the receiver is difficult to recover data because the intensity of brightness of LED (i.e., luminance) cannot be enough recognized from the image. However, the previous studies about the image-sensor-based VLC have not enough discussed the communication distance and the recognition of LED on the image, i.e., the receiving characteristics. We focus on the communication distance and investigates the relationship between the distance and the receiving characteristics in the image-sensor-based VLC.

  84. Outdoor Road-to-Vehicle Visible Light Communication Using On-Vehicle High-Speed Camera Reviewed

    C. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto

    International Journal of Intelligent Transportation Systems Research   Vol. 13 ( 1 ) page: 28-36   2015.1

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    We propose a road-to-vehicle Visible Light Communication (VLC) system for ITS. Here, the communication between road and a vehicle is approached using an LED array as a transmitter and an on-vehicle high-speed camera as a receiver. Modulation is conducted at the transmitter by blinking LEDs in high frequency and demodulation is conducted at the receiver by capturing the blinking patterns of the transmitter, by processing the high-speed camera images captured in high frame rate. This paper proposes an effective image processing method for capturing those blinking patterns. Out door communication experiments of the proposed VLC system are also present.

  85. Image sensor based visible light communication Reviewed

    Shinichiro Haruyama, Takaya Yamazato

    Visible Light Communication     page: 181 - 205   2015.1

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    Language:English   Publishing type:Part of collection (book)   Publisher:Cambridge University Press  

    Overview Image sensors are used in digital cameras and a large number of imaging devices for industrial, media, medical, and consumer electronics applications. An image sensor consists of a number of pixels
    each pixel contains a photodiode (PD), which is generally used as a receiver in visible light communications (VLC). Thus, an image sensor consisting of a number of pixels can also be used as a VLC receiver. A particular advantage of using image sensors, due to the massive number of available pixels, is the ability to spatially separate sources. Owing to the spatial separation of multiple sources, the VLC receiver uses only the pixels that sense LED transmission sources, discarding other pixels, including those sensing ambient noise. The ability to spatially separate sources also provides an additional feature to VLC, i.e., the ability to receive and process multiple transmitting sources. In this chapter, we introduce VLC using an image sensor [1]. After presenting an overview of image sensors in Section 9.2, we introduce the use of an image sensor as a VLC receiver in Section 9.3. We provide a design of an image sensor based VLC system in Section 9.4. In Sections 9.5 and 9.6, we respectively introduce the following two unique applications of VLC systems using an image sensor: (1) massively parallel visible light transmission that can theoretically achieve a maximum data rate of 1.28 Gigabits per second
    and (2) accurate sensor pose estimation that cannot be realized by a VLC system using a single-element PD. Applications of image sensor based communication are also presented in Section 9.7 for traffic signal communication, position measurements in civil engineering, and bridge position monitoring. Finally, in Section 9.8, we summarize our conclusions.

    DOI: 10.1017/CBO9781107447981.009

    Scopus

  86. Intensity Estimation of LEDs from Spatially and Temporally Mixed Images in Image Sensor Communication Reviewed

    Takazumi Asai, Daigo Iwase, Ryoko Ieki, Tomohiro Yendo, Shintaro Arai, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Koji Kamakura

    2015 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA)     page: 877 - 883   2015

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    We focus on the road-to-vehicle visible light communication that system is composed of LED matrix as transmitter and high-speed camera as receiver. In proposed method, there are two problems. First problem is in case of long distance. It is difficult to receive data correctly because neighboring LEDs on the received image are merged due to less number of pixels and/or blurring by defocus. In this paper, we propose estimation method of LED intensity from merged image. We evaluated the method by measuring Bit Error Rate and confirmed effectiveness of the method. We also performed real time communication and succeeded to extend communication distance from the previous work by applying the method. Second problem is that, the transmitting rate has been reduced to half of the frame rate of the camera, to avoid intersymbol interference because of exposure time of camera frame. We propose a method to improve the communication rate. The transmitting rate is set same to receiver's frame rate, and the sent data is estimated from pattern mixed image. Using 8b/10b encoding instead of conventional reversal pattern to reduce the flickering of transmitter's lighting is also proposed.

    DOI: 10.1109/APSIPA.2015.7415396

    Web of Science

    Scopus

  87. Novel Demodulation Scheme Based on Blurred Images for Image-Sensor-Based Visible Light Communication Reviewed

    Yuki Ohira, Shintaro Arai, Tomohiro Yendo, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Koji Kamakura

    2015 IEEE GLOBECOM WORKSHOPS (GC WKSHPS)     page: 1 - 6   2015

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This paper proposes a novel data detection scheme based on the occurrence of blurred output images in image-sensor-based visible light communication systems. This system's receiver suffers from an inability to detect correct LED luminance values and demodulation of data because the captured image blurs owing to defocusing. The proposed method assumes that the light emitted by all LEDs that is diffused by the blur can be approximated by applying a Gaussian filter and expresses all LED luminance values as convolution equations based on this diffusion of the LED light. We estimate each LED light's condition by simultaneously solving these convolution equations and recover data according to the estimated result. To confirm the accuracy of the proposed method, we conduct computer simulations and an implementation experiment to evaluate the bit error rate performance of the proposed method.

    DOI: 10.1109/GLOCOMW.2015.7414144

    Web of Science

    Scopus

  88. Layered Space-Time Coding Using LED Array for Image-Sensor-Based Visible Light Communications Reviewed

    Katsunori Ebihara, Koji Kamakura, Takaya Yamazato

    2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC)   Vol. 2015-September   page: 5048 - 5053   2015

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This paper demonstrates the feasibility of layered space-time coding (STC) in an outdoor image-sensor-based (IS-based) visible light communication (VLC) system. We examined that for low-resolution IS-based VLC channel where intensity modulated signals from two different light emitting diodes (LEDs) are detected at one pixel on the image plane, STC allows to decouple them, thus receiving data with no errors. Consequently, STC offers extending the transmission distance. In the layered STC presented here, additional bit streams are aligned in the 2(n) x 2(n) LED array for increasing the transmission rate per symbol duration for the case where the spatial resolution is improved. A prototype of three layered STC is built with an 8 x 8 LED array, where each of the LEDs is modulated at 1 kbps and a high-speed camera with IS operating at 1000 fps. Our experimental results validate that additional bit streams (layer-2 and -3), aligned in the layer-1 STC matrix pair, are extracted with no errors when the receiver comes within 155m and 55 m, respectively, from the LED array, without decreasing 210m of the transmission distance of layer-1 bit stream.

    DOI: 10.1109/ICC.2015.7249124

    Web of Science

    Scopus

  89. Development of add-on stochastic resonance device for the detection of subthreshold RF signals Reviewed

    Chiga Keita, Tanaka Hiroya, Yamazato Takaya, Tadokoro Yukihiro, Arai Shintaro

    IEICE NONLINEAR THEORY AND ITS APPLICATIONS   Vol. 6 ( 4 ) page: 520 - 533   2015

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    Web of Science

  90. Development of add-on stochastic resonance device for the detection of subthreshold RF signals Reviewed

    Keita Chiga, Hiroya Tanaka, Takaya Yamazato, Yukihiro Tadokoro, Shintaro Arai

    Nonlinear Theory and Its Applications, IEICE   Vol. 6 ( 4 ) page: 520 - 533   2015

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1587/nolta.6.520

    CiNii Article

  91. Intensity Estimation of LEDs from Spatially and Temporally Mixed Images in Image Sensor Communication Reviewed

    Asai Takazumi, Iwase Daigo, Ieki Ryoko, Yendo Tomohiro, Arai Shintaro, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Kamakura Koji

    2015 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA)     page: 877 - 883   2015

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  92. LED Acquisition Methods for Image-Sensor-Based Visible Light Communication Reviewed

    Shintaro Arai, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Tomohiro Yendo

    2015 OPTO-ELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC)     2015

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This invited paper focuses on a high-speed image sensor as a visible light communication (VLC) reception device to develop the intelligent transport systems (ITS) application using VLC technique. We refer to the VLC using a high-speed image sensor as image-sensor-based VLC. A major advantage of the image sensor is the ability to spatially separate multiple sources. Based on this ability, we proposed several methods for the image-sensor-based VLC in our previous researches. Especially, we focused on unique characteristics of the image sensor and proposed the hierarchical coding and the overlay coding to improve the data reception performance. However, to perform the image-sensor-based VLC in an actual environment, the receiver has to acquire the VLC transmitter from captured images before recovering data. Namely, the VLC transmitter acquisition and tracking are critical problem. the image-sensor-based VLC technique. This invited paper introduces two proposed methods to acquire the VLC transmitter from images captured by the image sensor.

    Web of Science

  93. LED Acquisition Methods for Image-Sensor-Based Visible Light Communication Reviewed

    Arai Shintaro, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Yendo Tomohiro

    2015 OPTO-ELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC)     2015

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  94. Layered Space-Time Coding Using LED Array for Image-Sensor-Based Visible Light Communications Reviewed

    Ebihara Katsunori, Kamakura Koji, Yamazato Takaya

    2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC)     page: 5048 - 5053   2015

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  95. Noise-Enhanced subthreshold signal reception by a stochastic resonance receiver using a non-dynamical device Reviewed

    Yukihiro Tadokro

    Nonlinear Theory and Its Applications, IEICE   Vol. 6 ( 2 ) page: 303 - 312   2015

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1587/nolta.6.303

    Web of Science

    CiNii Article

  96. Outdoor road-to-vehicle visible light communication using on-vehicle high-speed camera Reviewed

    Chinthaka Premachandra, Tomohiro Yendo, Mehrdad Panahpour Tehrani, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Masayuki Tanimoto

    International Journal of Intelligent Transportation Systems Research   Vol. 13 ( 1 ) page: 28 - 36   2015

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer New York LLC  

    We propose a road-to-vehicle Visible Light Communication (VLC) system for ITS. Here, the communication between road and a vehicle is approached using an LED array as a transmitter and an on-vehicle high-speed camera as a receiver. Modulation is conducted at the transmitter by blinking LEDs in high frequency and demodulation is conducted at the receiver by capturing the blinking patterns of the transmitter, by processing the high-speed camera images captured in high frame rate. This paper proposes an effective image processing method for capturing those blinking patterns. Out door communication experiments of the proposed VLC system are also present.

    DOI: 10.1007/s13177-014-0079-y

    Scopus

  97. Novel Demodulation Scheme Based on Blurred Images for Image-Sensor-Based Visible Light Communication Reviewed

    Ohira Yuki, Arai Shintaro, Yendo Tomohiro, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Kamakura Koji

    2015 IEEE GLOBECOM WORKSHOPS (GC WKSHPS)     2015

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  98. Optical Camera Communications Using Digital Signage Reviewed

    OKADA Hiraku, SATO Sho, WADA Tadahiro, YAMAZATO Takaya, KATAYAMA Masaaki

    ITE Technical Report   Vol. 39 ( 0 ) page: 21 - 24   2015

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    In this paper, we discuss optical cammera communication systems using digital signage, which is composed of a liquid crystal display (LCD). The digital signage, which is used as a transmitter, displays advertisement contents as visual information. The optical camera communication system using digital signage has to transmit data information not to obstruct the visual information. In this paper, we propose blue color difference modulation for the optical camera communication system using digital signage. We clarify the performance of the proposed system by data transmission experiments.

    DOI: 10.11485/itetr.39.38.0_21

    CiNii Article

  99. Cooperative Diversity via Simple Relaying with Quasi-Orthogonal Space-Time Block Code Reviewed

    T. Yamaoka, Y. Hara, K. Ishioka, T. Hara, T. Yamazato

    IEICE Transaction on Communication     page: -   2014.12

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    We have been proposed cooperative diversity receiving ABBA code as cooperative diversity via simple relaying with QOSTBC(Quasi-Orthogonal Space-Time Block Code). This scheme offers codinggain by permutation of space-time coded signal sequences in the relay nodes. So the relay nodes don't need carrier recovery and complete the signal process in the intermediate frequency band. In this paper we discuss two improved scheme with various channel model. These schemes improve the previous scheme without loss of the merit in its relay process. Moreover we sum up cooperative diversity via simple relaying with QOSTBC to discuss these schemes with various channel model. We evaluate effect of these scheme in terms of signal matrixes and simulate bit error rate of the prposed and improved scheme with with various channel model, respectively.

  100. Alamouti-Type Space Time Coding for Visible Light Communication Based on Direct Detection Using Image Sensor Reviewed

    Y. Amano, K. Kamakura, T. Yamazato

    IEICE Transactions on Communications (to be published)     page: -   2014.12

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    This paper proposes Alamouti-type space time (ST) coding to visible light communication (VLC) using light emitting diodes (LEDs) and image sensor-based direct detection with a high-speed camera. Although multiple LEDs of an array are used as transmitters to communicate to individual pixel elements of an image sensor which act as multiple receive elements, the received signal is essentially the image of the transmitting element, whose size in pixel reduces with distance. When the receiver captures the LED array at a distance where images of two neighboring LEDs in the array are not separated at the image plane, such distortion depreciates the symbol decision quality. Our proposed scheme aims at expanding the communication range limited by the pixel resolution of image sensor. Our implemented prototype demonstrates that ST coding is feasible to achieve 48-meter error-free transmission range while the repetition transmission achieves 26-meter error-free range.

  101. Motion Modeling of Mobile Transmitter for Image Sensor Based I2V-VLC, V2I-VLC, and V2V-VLC Reviewed

    M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura

    IEEE Workshop on Optical Wireless Communications     page: -   2014.12

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    Language:English   Publishing type:Research paper (scientific journal)  

    Visible light communication (VLC) using light-emitting diodes (LEDs) is drawing much attention. There are two types of VLC reception devices, a photodiode and an image sensor. VLC using image sensor is called image sensor based VLC. As the receiver only uses the image sensor pixels that sense LED transmission sources and discards other pixels, including those sensing noise sources, image sensor based VLC is an attractive solution for outdoor mobile applications. However, little evidence is available for channel modeling of image sensor based VLC in mobile outdoor environments, especially for motion modeling of VLC transmitter. In this paper, we propose a motion model of VLC transmitter. In particular, we consider three cases; infrastructure-to-vehicle VLC (I2V-VLC), vehicle-to-infrastructure VLC (V2I-VLC), and vehicle-to-vehicle VLC (V2V-VLC). As a result, we show that the motion model of the VLC transmitter on the captured image for the three aforementioned situations (i.e., I2V-VLC, V2I-VLC, and V2V-VLC) can be expressed in the identical pinhole camera model.

  102. Cooperative Diversity via Simple Relaying with Quasi-Orthogonal Space-Time Block Code Reviewed

    Tomoya YAMAOKA, Yoshitaka HARA, Kazuaki ISHIOKA Teruyuki HARA, Takaya Yamazato

    IEICE Transactions on Communications   Vol. J97-B ( 12 ) page: 1213-1223   2014.12

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    We have been proposed cooperative diversity receiving ABBA code as cooperative diversity via simple relaying with QOSTBC(Quasi-Orthogonal Space-Time Block Code). This scheme offers coding gain by permutation of space-time coded signal sequences in the relay nodes. So the relay nodes don't need carrier recovery and complete the signal process in the intermediate frequency band. In this paper, we discuss two improved scheme with various channel model. These schemes improve the previous scheme without loss of the merit in its relay process. Moreover, we sum up cooperative diversity via simple relaying with QOSTBC to discuss these schemes with various channel model. We evaluate effect of these scheme in terms of signal matrixes and simulate bit error rate of the prposed and improved scheme with with various channel model, respectively.

  103. Investigation on Relationship between Communication Distance and Receiving Characteristic in Visible Light Communication Using LED and High-Speed Camera Reviewed

    E. Souke, Y. Ohira, S. Arai, T. Yamazato, T. Yendo, H. Okada, T. Fujii and K. Kamakura

    Proceedings of 2014 IEEE Workshop on Nonlinear Circuit Networks (NCN'14)     page: 93-94   2014.12

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    The present paper considers an optical spatial channel in visible light communication (VLC) using LED and a high-speed camera. In general, the optical spatial channel affects the communication performance. However, the previous studies have not enough discussed the channel for VLC. This study focuses on the communication distance, which is one of channel parameters, and investigates the relationship between the distance and a receiving characteristic in the VLC.

  104. Layered Space-Time Coding Using LED Array for Image-Sensor-Based Visible Light Communications Reviewed

    EBIHARA Katsunori, KAMAKURA Koji, YAMAZATO Takaya

    IEICE technical report. Communication systems   Vol. 114 ( 289 ) page: 81 - 86   2014.11

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper demonstrates the feasibility of layered space-time coding (STC) in an outdoor image-sensor-based (IS-based) visible light communication (VLC) system. We examined that for low-resolution IS-based VLC channel where intensity modulated signals from two different light emitting diodes (LEDs) are detected at one pixel on the image plane, STC allows to decouple them, thus receiving data with no errors. Consequently, STC offers extending the transmission distance. In the layered STC presented here, additional bit streams are aligned in the 2^n × 2^n LED array for increasing the transmission rate per symbol duration for the case where the spatial resolution is improved. A prototype of three layered STC is built with an 8 × 8 LED array. Our experimental results validate that additional bit streams (layer-2 and -3), aligned in the layer-1 STC matrix pair, are extracted with no errors when the receiver comes within 155m and 55m, respectively, from the LED array, without decreasing 210m of the transmission distance of layer-1 bit stream.

    CiNii Article

  105. Channel Fluctuation Measurement for Image Sensor Based I2V-VLC, V2I-VLC, and V2V-VLC Reviewed

    M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura

    2014 IEEE Asia Pacific Conferece on Circuits and Systems     page: -   2014.11

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    Language:English  

    In image sensor based VLC, transmitter acquisition and tracking are critical issue. However, the fluctuation of the VLC transmitter in the image plane caused by vehicle movement, complicates correct data reception. Therefore, in this paper, we present results of channel fluctuation measurements for infrastructure-to-vehicle VLC (I2V-VLC), vehicleto- infrastructure VLC (V2I-VLC), and vehicle-to-vehicle VLC (V2V-VLC). We analyze channel fluctuation in terms of optical flow from measured data.

  106. データを伴う照明 Invited Reviewed

    山里敬也

    電波技術協会報     page: -   2014.11

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    Authorship:Lead author   Language:Japanese  

    可視光通信とは,LEDを人の目に分からないほど高速に点滅(変調)させることで情報伝送を行う通信のことである.可視光通信では発光ダイオード(light emitting diode: LED)を送信デバイスに用いるのだが,LEDはものすごい勢いで普及が進みつつあり,それこそ至る所にある.つまりLEDにデータ伝送機能を追加する可視光通信はユビキタスのインフラ基盤になりうるのである.

  107. BER Characteristic of Optical-OFDM using OCI Reviewed

    Y. Goto, I. Takai, T. Yamazato, H. Okada, T. Fujii, S. Kawahito, S. Arai, T. Yendo, K. Kamakura

    2014 IEEE Asia Pacific Conferece on Circuits and Systems     page: -   2014.11

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    Light-emitting diode (LED) transmitters based optical wireless communication (OWC) systems offer the potential for new generation communication systems. Particularly, an image sensor based OWC systems consist of the LED transmitters and camera receivers are expected to contribute to intelligent transport system (ITS) for driving supports. For high achievable data rates, orthogonal frequency division multiplexing (OFDM) based OWC systems have attracted a great deal of attention. Despite attractive features of optical OFDM, only few attempts have so far been made to adopt it as a modulation scheme of an image sensor based OWC system. There remains a need for an evaluation of adopting an optical OFDM to the image sensor based OWC systems. Another important issue needs to be addressed is the performance degradation due to a frequency response of an actual image sensor device, especially a signal attenuation loss in higher frequency. In addition to such loss, a narrow band noise generated by its circuits also degrades the performance. The purpose of this paper is to investigate BER performances of the optical-OFDM using an actual image sensor device, the optical communication image sensor (OCI). From simulation results, it is found that the frequency response and the narrowband noise at 12MHz of the OCI lead to the significant reduction of BER performances. Additionally, the results shows that ACO-OFDM shows a little better performance compared to DCO-OFDM with the same bandwidth efficiency.

  108. A Novel Study on Coded Modulation with Triangular Costellation Reviewed

    YAMAOKA Tomoya, HARA Teruyuki, OKAZAKI Akihiro, YAMAZATO Takaya

    Technical report of IEICE. RCS   Vol. 114 ( 254 ) page: 111 - 116   2014.10

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    For improvement of the coded modulation, we propose the signal sets with triangular constellation and label shaping. The proposed signal set can gain the merits of them despite of a few signal points and a simple modification. We indicate the channel capacity, PAPR (Peak to Average Power Ratio), BER (Bit Error Rate) in case of BICM-ID (Bit Interleaved Coded Modulation with Iterative Decoding) and PAPR with band limited of the 7APSK (Amplitude and Phase-Shift Keying) and modified 14APSK. Especially, the results shows modified 14APSK we proposed can improve 16QAM (Quadrature Amplitude Modulation) in terms of BER and PAPR, simultaneously.

    CiNii Article

  109. A Transmit Diversity with a Simple Transmitter Reviewed

    YAMAOKA Tomoya, HARA Teruyuki, OKAZAKI Akihiro, YAMAZATO Takaya

    Technical report of IEICE. RCS   Vol. 114 ( 254 ) page: 117 - 122   2014.10

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we proposed a transmit diversity with a simple transmitter. Specifically, we connect simplex RF (Radio Frequency) circuits with two antennas and transmit the signals whose phases are rotated and IQ component are interleaved alternately via two antennas. In the receiver, the signals with the signal space diversity are received in spite of the simple transmitter. So we can achieve space diversity and reliable wireless communications. In the performance evaluation, we confirm the 4dB gain at BER=10^<-2> in bit error rate performance.

    CiNii Article

  110. ITS Visible Light Communication using High-Speed Image Sensor Invited

    Takaya Yamazato

    The 133 Microoptics Meeting, Optical Society of Japan/The Japan Society of Applied Physics     page: -   2014.10

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    Authorship:Lead author   Language:Japanese  

    This paper presents the visible light communication using image sensor and its application to intelligent transport systems (ITS). As an example, mage-sensor based VLC for automotive application that is currently carried out by the author is also introduced. The paper is a continuation of the paper by Prof. Matsumoto, "Evaluation of optical wireless communication," and by Prof. Haruyama, "Recent trends of visible light communication," appeared on 2014 March issue of Microoptics News.

  111. Channel Fluctuation Measurement for I2V-VLC, V2I-VLC, and V2V-VLC Using Image Sensor Reviewed

    KINOSHITA Masayuki, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, ARAI Shintaro, YENDO Tomohiro, KAMAKURA Koji

      Vol. 114 ( 225 ) page: 77 - 81   2014.9

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In image sensor based VLC for automotive applications, transmitter acquisition and tracking are critical. However, the fluctuation of the VLC transmitter in the image plane caused by vehicle movement, complicates correct data reception. Therefore, in this paper, we present results of channel fluctuation measurements for automotive applications. Especially, we examined the channel fluctuation based on mobile movements in the image plane detected by phase only correlation (POC) in the subpixel accuracy.

    CiNii Article

  112. Channel Fluctuation Measurement for I2V-VLC, V2I-VLC, and V2V-VLC Using Image Sensor Reviewed

    Masayuki Kinoshita, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Shintaro Arai, Tomohiro Yendo, Koji Kamakura

      Vol. 2014 ( 13 ) page: 1 - 5   2014.9

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    Publishing type:Research paper (scientific journal)   Publisher:Information Processing Society of Japan (IPSJ)  

    In image sensor based VLC for automotive applications, transmitter acquisition and tracking are critical. However, the fluctuation of the VLC transmitter in the image plane caused by vehicle movement, complicates correct data reception. Therefore, in this paper, we present results of channel fluctuation measurements for automotive applications. Especially, we examined the channel fluctuation based on mobile movements in the image plane detected by phase only correlation (POC) in the subpixel accuracy.

    CiNii Article

  113. A-2-7 An influence of Noise Bandwidth on an application of Stochastic Resonance to Radio Communication Reviewed

    CHIGA Keita, TANAKA Hiroya, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the Society Conference of IEICE   Vol. 2014   2014.9

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

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  114. A-5-2 A Study on Influence of Communication Distance in Visible Light Communication Using LED and High-Speed Camera Reviewed

    SOUKE Eisho, OHIRA Yuki, ARAI Shintaro, YAMAZATO Takaya, YENDO Tomohiro, OKADA Hiraku, FUJII Toshiaki, KAMAKURA Koji

    Proceedings of the Society Conference of IEICE   Vol. 2014   2014.9

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  115. A-5-1 A Study on Signal Demodulation Method Based on Blurred Camera Image in Visible Light Communication Using LED Array and High-Speed Camera Reviewed

    OHIRA Yuki, ARAI Shintaro, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, KAMAKURA Koji

    Proceedings of the Society Conference of IEICE   Vol. 2014   2014.9

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  116. LEDアレーと高速度カメラを用いた可視光通信における画像のボケの影響を考慮した信号復調手法の一検討

    大平祐生,荒井伸太郎,圓道知博,山里敬也,岡田啓,藤井俊彰,鎌倉浩嗣

    電子情報通信学会 基礎・境界ソサイエティ大会     page: -   2014.9

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  117. Image Sensor Based Visible Light Communication and Its Application to Pose, Position, and Range Estimations

    T. Yamazato, S. Haruyama

    IEICE Transactions on Communications   Vol. E97-B ( 9 ) page: 1759-1765   2014.9

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    This study introduces an image sensor based visible light communication (VLC) and its application to pose, position, and range estimations. There are two types of visible-light receiver: a photodiode and an image sensor. A photodiode is usually used as a reception device of VLC, and an image sensor consisting of a large number of pixels can also be used as a VLC reception device. A photodiode detects the signal intensity of incoming light, while an image sensor not only detects the incoming signal intensity but also an accurate angle of arrival of light emitted from a visible light transmitter such as a white LED light. After angles of arrival of light are detected by an image sensor, positioning and data reception can be performed. The ability of an image sensor to detect an accurate angle of arrival will provide attractive applications of VLC such as pose, position calculation, and range estimation. Furthermore, because the image sensor has the ability to spatially separate sources, outdoor positioning even with strong sunlight is possible by discarding the associated pixels of noise sources.

  118. SNR Improvement by Stochastic Resonance Receiver for Subthreshold Signal in Radio Frequency

    K. Chiga, H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai

    International Symposium on Nonlinear Theory and its Application     page: -   2014.9

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    Stochastic Resonance (SR) is well known as a phenomenon in which the weak signal in a nonlinear system can be detected by added noise. We consider the application of SR phenomenon to a wireless communication system. The receiver using SR phenomenon can detect the subthreshold signal which is not detectable by the conventional receiver. The effect of SR receiver has been verified, but it has never been verified in radio frequency which is used by a wireless system. In this paper, we consider the implementation of SR System for Radio Frequency and evaluate its performance of Signal to Noise Ratio (SNR).

  119. An influence of Noise Bandwidth on an application of Stochastic Resonance to Radio Communication

    K. Chiga, H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai

    Enginnering Sciences Society Conference of IEICE     page: -   2014.9

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    Language:Japanese  

  120. An Analysis Method of a Stochastic Resonance Receiver using a Schmitt Trigger

    H. Tanaka, K. Chiga, T. Yamazato, Y. Tadokoro, and S. Arai

    International Symposium on Nonlinear Theory and its Application     page: 193-196   2014.9

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    Language:English  

    Stochastic resonance (SR) enhances system responses by increasing noise. By applying SR to a receiver, a subthreshold signal not receivable by a conventional linear receiver could be received. Previously, we proposed an analysis method of the SR receiver using a comparator, and evaluated its bit error rate performance. The comparator is known as a simple non-dynamical system exhibiting SR. However, a dynamical system can have better performance since it has a memory effect. In this sense, we propose an analysis method of the SR receiver using a Schmitt trigger known as a simple dynamical system, and evaluate its bit error rate performance. A performance comparison of the comparator and the Schmitt trigger is also shown.

  121. Channel Fluctuation Measurement for I2V-VLC, V2I-VLC, and V2V-VLC Using Image Sensor

    M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura

    IEICE Technical Report   Vol. ITS2014-18   page: 77-81   2014.9

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    Language:Japanese  

    In image sensor based VLC for automotive applications, transmitter acquisition and tracking are criti- cal. However, the uctuation of the VLC transmitter in the image plane caused by vehicle movement, complicates correct data reception. Therefore, in this paper, we present results of channel uctuation measurements for automo- tive applications. Especially, we examined the channel uctuation based on mobile movements in the image plane detected by phase only correlation (POC) in the subpixel accuracy.

  122. LEDと高速度カメラを用いた可視光通信における通信距離の影響に関する一検討

    曹家永翔,大平祐生,荒井伸太郎,山里敬也,圓道知博,岡田啓,藤井俊彰,鎌倉浩嗣

    電子情報通信学会 基礎・境界ソサイエティ大会     page: -   2014.9

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  123. Image Sensor Based Visible Light Communication and Its Application to Pose, Position, and Range Estimations Reviewed

    Takaya Yamazato, Shinichiro Haruyama

    IEICE TRANSACTIONS ON COMMUNICATIONS   Vol. E97B ( 9 ) page: 1759 - 1765   2014.9

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    Publishing type:Research paper (scientific journal)   Publisher:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    This study introduces an image sensor based visible light communication (VLC) and its application to pose, position, and range estimations. There are two types of visible-light receiver: a photodiode and an image sensor. A photodiode is usually used as a reception device of VLC, and an image sensor consisting of a large number of pixels can also be used as a VLC reception device. A photodiode detects the signal intensity of incoming light, while an image sensor not only detects the incoming signal intensity but also an accurate angle of arrival of light emitted from a visible light transmitter such as a white LED light. After angles of arrival of light are detected by an image sensor, positioning and data reception can be performed. The ability of an image sensor to detect an accurate angle of arrival will provide attractive applications of VLC such as pose, position calculation, and range estimation. Furthermore, because the image sensor has the ability to spatially separate sources, outdoor positioning even with strong sunlight is possible by discarding the associated pixels of noise sources.

    DOI: 10.1587/transcom.E97.B.1759

    Web of Science

    Scopus

    CiNii Article

  124. Performance evaluation of stochastic resonance receiver using Schmitt trigger

    Hiroya Tanaka, Keita Chiga, Takaya Yamazato, Yukihiro Tadokoro, Shintaro Arai

    IEICE Complex Communication Sciences     page: -   2014.8

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    Language:Japanese  

  125. Distance Estimation Scheme for Integrated V2I-VLC for driving vehicle Reviewed

    A. Ohmura, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai, K. Kamakura

    IEICE Transaction on Communications   Vol. J97-B ( 8 ) page: 695-696   2014.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    A distance estimation scheme for vehicle to infrastructure using visible light communication is discussed. As vehicle vibration severely affect the distance estimation performance, we introduce a new LED lighting patterns for the distance estimation. As the result, we acheive nearly the same distance estimation performance for the case of non-driving.

  126. Optical Signal Detection by Stochastic Resonance Receiver Using Schmitt Trigger for LED Visible Light Communications

    S. Arai, T. Yamazato, Y. Tadokoro

    The 27th Workshop on Circuits and Systems     page: 116-120   2014.8

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    Language:Japanese  

  127. Distance Estimation Scheme for Integrated V2I-VLC for driving vehicle Reviewed

    A. Ohmura, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai, K. Kamakura

    IEICE Transaction on Communications   Vol. J97-B ( 8 ) page: 695-696   2014.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

  128. A New LED Array Acquisition Method Focusing on Time-gradient and Space-gradient Values for Road to Vehicle Visible Light Communication Reviewed

    S.Usui, T.Yamazato, H.Okada, T.Fujii, K.Takahashi, T.Yendo, S.Arai

    IEICE Transactions on Communications   Vol. J97-B ( 7 ) page: 536-545   2014.7

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    This paper proposes a new LED acquisition method for visible light communication systems using an LED array as a transmitter and a high-speed camera as a receiver for road-to-vehicle communications. The first process of the receiver is to search the target LED array from the captured image (LED array acquisition). This paper focuses on the time-gradient and the space-gradient values in the captured images, and draws both gradient value as a scatter diagram. This scatter diagram enables us to regard the LED acquisition as discriminant analysis. From the above, this paper proposes a new acquisition method and confirms its effectiveness by the experiment in a driving situation.

  129. A New LED Array Acquisition Method Focusing on Time-gradient and Space-gradient Values for Road to Vehicle Visible Light Communication Reviewed

    S.Usui, T.Yamazato, H.Okada, T.Fujii, K.Takahashi, T.Yendo, S.Arai

    IEICE Transactions on Communications   Vol. J97-B ( 7 ) page: 536-545   2014.7

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

  130. Image-Sensor-Based Visible Light Communication for Automotive Applications Reviewed

    Takaya Yamazato, Isamu Takai, Hiraku Okada, Toshiaki Fujii, Tomohiro Yendo, Shintaro Arai, Michinori Andoh, Tomohisa Harada, Keita Yasutomi, Keiichiro Kagawa, Shoji Kawahito

    IEEE COMMUNICATIONS MAGAZINE   Vol. 52 ( 7 ) page: 88 - 97   2014.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    The present article introduces VLC for automotive applications using an image sensor. In particular, V2I-VLC and V2V-VLC are presented. While previous studies have documented the effectiveness of V2I and V2V communication using radio technology in terms of improving automotive safety, in the present article, we identify characteristics unique to image-sensor-based VLC as compared to radio wave technology. The two primary advantages of a VLC system are its line-of-sight feature and an image sensor that not only provides VLC functions, but also the potential vehicle safety applications made possible by image and video processing. Herein, we present two ongoing image-sensor-based V2I-VLC and V2V-VLC projects. In the first, a transmitter using an LED array (which is assumed to be an LED traffic light) and a receiver using a high-frame-rate CMOS image sensor camera is introduced as a potential V2I-VLC system. For this system, real-time transmission of the audio signal has been confirmed through a field trial. In the second project, we introduce a newly developed CMOS image sensor capable of receiving highspeed optical signals and demonstrate its effectiveness through a V2V communication field trial. In experiments, due to the high-speed signal reception capability of the camera receiver using the developed image sensor, a data transmission rate of 10 Mb/s has been achieved, and image (320 x 240, color) reception has been confirmed together with simultaneous reception of various internal vehicle data, such as vehicle ID and speed.

    DOI: 10.1109/MCOM.2014.6852088

    Web of Science

    Scopus

  131. Derivation of the Max of Sensitivity Improvement Rate of Stochastic Resonance Receiver for Subthreshold Bi-Polar Pulse

    H. Tanaka, K. Chiga, T. Yamazato, Y. Tadokoro, S. Arai

    IEICE General Conference   ( A-2-15 ) page: p.40   2014.3

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    Language:Japanese  

  132. A Study on Adaptation of Optical OFDM to Visible Light Communication using Optical Communication Imaging Sensor

    Y.Goto,T.Yamazato,H.Okada,T.Fujii,I.Takai,S.Kawahito,T.Yendo,S.Arai,K.Kamakura

    IEICE General Conference   ( B-10-20 ) page: p.388   2014.3

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  133. A-2-15 Derivation of the Max of Sensitivity Improvement Rate of Stochastic Resonance Receiver for Subthreshold Bi-Polar Pulse Reviewed

    TANAKA Hiroya, CHIGA Keita, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the IEICE General Conference   Vol. 2014   2014.3

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  134. B-10-20 A Study on Adaptation of Optical OFDM to Visible Light Communication using Optical Communication Imaging Sensor Reviewed

    GOTO Yuki, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, TAKAI Isamu, KAWAHITO Shoji, ARAI Shintaro, YENDO Tomohiro, KAMAKURA Koji

    Proceedings of the IEICE General Conference   Vol. 2014 ( 2 )   2014.3

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  135. IEICE Knowledge Discovery(I-Scover) Reviewed

    Takaya Yamazato, Yasubumi Chimura, Fumihito Nishino, Satoshi Ikada, Toyokazu Akiyama, Miyuki Nakano, Yuji Inoue

    The Journal of IEICE   Vol. 97 ( 3 ) page: 240-246   2014.3

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    Authorship:Lead author   Language:Japanese   Publishing type:Research paper (scientific journal)  

    I-Scover, officially known as IEICE Knowledge Discovery, is a new reference search engine developed by the Institute of Electronics, Information and Communication Engineers (IEICE). It is not just a system for cross-searching articles published by IEICE. It also aims to maximize significance of the IEICE articles by organically linking related information with the articles, making them accessible on the Internet for many users. With I-Scover, berry-picking exploratory search, which has been difficult with conventional reference search engines, is possible. In this article, we will describe I-Scover in terms of its developmental background and aim, introduce its various features and characteristics, and discuss the promotional activity plan to spread I-Scover, as well as its future development plans.

  136. IEICE knowledge discovery (I-Scover) Reviewed

    Yamazato T.

    Journal of the Institute of Electronics, Information and Communication Engineers   Vol. 97 ( 3 ) page: 240 - 246   2014.3

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    Publishing type:Research paper (scientific journal)   Publisher:Journal of the Institute of Electronics, Information and Communication Engineers  

    Scopus

  137. IEICE Knowledge Discovery (I-Scover) Reviewed

    YAMAZATO Takaya, CHIMURA Yasubumi, NISHINO Fumihito, IKADA Satoshi, AKIYAMA Toyokazu, NAKANO Miyuki, INOUE Yuji

    The Journal of the Institute of Electronics, Information, and Communication Engineers   Vol. 97 ( 3 ) page: 240 - 246   2014.3

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  138. Preliminary Study on LED VLC with Simple SR Receiver Using Schmitt Trigger Reviewed

    H. Yokota, S. Arai, T. Yamazato and Y. Tadokoro

    Proceedings of 2014 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP'14)     page: pp. 61-64.   2014.2

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    Language:English  

    The present paper focuses on an application of Stochastic Resonance (SR) for an LED visible light communication (LED-VLC) receiver. SR is well-known as a phenomenon, which enhances the response by additive noise. We consider that a weak optical signal, which is distorted due to an influence of ambient light noise, can be detected by using SR system. This study makes a simple SR circuit for LED VLC and performs its circuit experiment for exploring the possibility and availability of the LED-VLC receiver using SR system.

  139. Alamouti-Type Coding for Visible Light Communication Based on Direct Detection Using Image Sensor

    Y. Amano, K. Kamakura, T. Yamazato

    IEICE Technical Report   ( ITS2013-37 ) page: pp.43-48   2014.2

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    Language:Japanese  

    This paper proposes Alamouti-type space time (ST) coding to visible light communication (VLC) using light emitting diodes (LEDs) and image sensor with a high-speed camera. Although multiple LEDs of an array are used as transmitters, the received signal is essentially the image of the transmitting element, whose size in pixel reduces with distance. When the receiver captures the LED array at a distance where images of two neighboring LEDs in the array are not separated at the image plane, such distortion depreciates the symbol decision quality. Our proposed scheme aims at expanding the communication range limited by the pixel resolution of image sensor. Our implemented prototype demonstrates that ST coding is feasible to achieve 48,m error-free transmission range while the repetition transmission achieves 26,m error-free range.

  140. LED Array Acquisition Method Based on Time-gradient and Space-gradient Values for Road to Vehicle Visible Light Communication Using High-Speed Camera

    S.Usui, T.Yamazato, H.Okada, T.Fujii, K.Takahashi, T.Yendo, S.Arai

    IEICE Technical Report   ( ITS2013-39 ) page: pp.55-60   2014.2

     More details

    Language:Japanese  

    This paper focuses on road-to-vehicle visible light communication using an LED array as a transmitter and a high-speed camera as a receiver. In this communication, LED array acquisition has a significant role. The spatio-temporal images are essential for a robust LED array acquisition because the time-gradient and space-gradient values can be an important feature value of an LED array. In this paper, we focus on the time-gradient and the space-gradient values in the captured images and draws both gradient value as a scatter diagram. This scatter diagram enables us to regard the LED acquisition as discriminant analysis. From the above, this paper proposes a new acquisition method and confirms its effectiveness by the experiment in a driving situation.

  141. Distance Estimation Scheme for Integrated V2I-VLC in Driving Vehicle

    A. Ohmura, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai, K. Kamakura

    IEICE Technical Report   ( ITS2013-38 ) page: pp.49-54   2014.2

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    Language:Japanese  

    This paper discusses an issue of estimating the distance between an on-vehicle transmitter and a roadside equipment for vehicular-to-infrastructure visible light communication (V2I-VLC). The system integrates the VLC as well as distance estimation functions. In this paper, we discuss a technique overcoming a vehicle vibration by using a particular transmitting LED pattern and the sub-pixel estimation using the phase-only correlation. As the results, we achieve less than 0.5m errors for the distance up to 60 m by the proposed system.

  142. Alamouti-Type Coding for Visible Light Communication Based on Direct Detection Using Image Sensor Reviewed

    AMANO Yuta, KAMAKURA Koji, YAMAZATO Takaya

      Vol. 113 ( 433 ) page: 43 - 48   2014.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper proposes Alamouti-type space time (ST) coding to visible light communication (VLC) using light emitting diodes (LEDs) and image sensor with a high-speed camera. Although multiple LEDs of an array are used as transmitters, the received signal is essentially the image of the transmitting element, whose size in pixel reduces with distance. When the receiver captures the LED array at a distance where images of two neighboring LEDs in the array are not separated at the image plane, such distortion depreciates the symbol decision quality. Our proposed scheme aims at expanding the communication range limited by the pixel resolution of image sensor. Our implemented prototype demonstrates that ST coding is feasible to achieve 48m error-free transmission range while the repetition transmission achieves 26 m error-free range.

    CiNii Article

  143. Alamouti-Type Coding for Visible Light Communication Based on Direct Detection Using Image Sensor Reviewed

    AMANO Yuta, KAMAKURA Koji, YAMAZATO Takaya

    IEICE technical report. Image engineering   Vol. 113 ( 434 ) page: 43 - 48   2014.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper proposes Alamouti-type space time (ST) coding to visible light communication (VLC) using light emitting diodes (LEDs) and image sensor with a high-speed camera. Although multiple LEDs of an array are used as transmitters, the received signal is essentially the image of the transmitting element, whose size in pixel reduces with distance. When the receiver captures the LED array at a distance where images of two neighboring LEDs in the array are not separated at the image plane, such distortion depreciates the symbol decision quality. Our proposed scheme aims at expanding the communication range limited by the pixel resolution of image sensor. Our implemented prototype demonstrates that ST coding is feasible to achieve 48m error-free transmission range while the repetition transmission achieves 26 m error-free range.

    CiNii Article

  144. Distance Estimation Scheme for Integrated V2I-VLC in Driving Vehicle Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro, KAMAKURA Koji

      Vol. 113 ( 433 ) page: 49 - 54   2014.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper discusses an issue of estimating the distance between an on-vehicle transmitter and a road-side equipment for vehicular-to-infrastructure visible light communication (V2I-VLC). The system integrates the VLC as well as distance estimation functions. In this paper, we discuss a technique overcoming a vehicle vibration by using a particular transmitting LED pattern and the sub-pixel estimation using the phase-only correlation. As the results, we achieve less than 0.5m errors for the distance up to 60 m by the proposed system.

    CiNii Article

  145. LED Array Acquisition Method Based on Time-gradient and Space-gradient Values for Road to Vehicle Visible Light Communication Using High-Speed Camera Reviewed

    USUI Syunsuke, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, TAKAHASHI Keita, ARAI Shintaro, YENDO Tomohiro

    IEICE technical report. Image engineering   Vol. 113 ( 434 ) page: 55 - 60   2014.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper focuses on road-to-vehicle visible light communication using an LED array as a transmitter and a high-speed camera as a receiver. In this communication, LED array acquisition has a significant role. The spatio-temporal images are essential for a robust LED array acquisition because the time-gradient and space-gradient values can be an important feature value of an LED array. In this paper, we focus on the time-gradient and the space-gradient values in the captured images and draws both gradient value as a scatter diagram. This scatter diagram enables us to regard the LED acquisition as discriminant analysis. Prom the above, this paper proposes a new acquisition method and confirms its effectiveness by the experiment in a driving situation.

    CiNii Article

  146. LED Array Acquisition Method Based on Time-gradient and Space-gradient Values for Road to Vehicle Visible Light Communication Using High-Speed Camera Reviewed

    USUI Syunsuke, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, TAKAHASHI Keita, ARAI Shintaro, YENDO Tomohiro

      Vol. 113 ( 433 ) page: 55 - 60   2014.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper focuses on road-to-vehicle visible light communication using an LED array as a transmitter and a high-speed camera as a receiver. In this communication, LED array acquisition has a significant role. The spatio-temporal images are essential for a robust LED array acquisition because the time-gradient and space-gradient values can be an important feature value of an LED array. In this paper, we focus on the time-gradient and the space-gradient values in the captured images and draws both gradient value as a scatter diagram. This scatter diagram enables us to regard the LED acquisition as discriminant analysis. Prom the above, this paper proposes a new acquisition method and confirms its effectiveness by the experiment in a driving situation.

    CiNii Article

  147. Distance Estimation Scheme for Integrated V2I-VLC in Driving Vehicle Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro, KAMAKURA Koji

    IEICE technical report. Image engineering   Vol. 113 ( 434 ) page: 49 - 54   2014.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper discusses an issue of estimating the distance between an on-vehicle transmitter and a road-side equipment for vehicular-to-infrastructure visible light communication (V2I-VLC). The system integrates the VLC as well as distance estimation functions. In this paper, we discuss a technique overcoming a vehicle vibration by using a particular transmitting LED pattern and the sub-pixel estimation using the phase-only correlation. As the results, we achieve less than 0.5m errors for the distance up to 60 m by the proposed system.

    CiNii Article

  148. Preliminary Study on LED VLC with Simple SR Receiver Using Schmitt Trigger

    H. Yokota, S. Arai, T. Yamazato and Y. Tadokoro

    Proceedings of 2014 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP'14)     page: 61-64   2014.2

     More details

    Language:English  

    The present paper focuses on an application of Stochastic Resonance (SR) for an LED visible light communication (LED-VLC) receiver. SR is well-known as a phenomenon, which enhances the response by additive noise. We consider that a weak optical signal, which is distorted due to an influence of ambient light noise, can be detected by using SR system. This study makes a simple SR circuit for LED VLC and performs its circuit experiment for exploring the possibility and availability of the LED-VLC receiver using SR system.

  149. LED Array Acquisition Method Based on Time-gradient and Space-gradient Values for Road to Vehicle Visible Light Communication Using High-Speed Camera

    S.Usui, T.Yamazato, H.Okada, T.Fujii, K.Takahashi, T.Yendo, S.Arai

    IEICE Technical Report   Vol. ITS2013-39   page: 55-60   2014.2

     More details

    Language:Japanese  

    This paper focuses on road-to-vehicle visible light communication using an LED array as a transmitter and a high-speed camera as a receiver. In this communication, LED array acquisition has a significant role. The spatio-temporal images are essential for a robust LED array acquisition because the time-gradient and space-gradient values can be an important feature value of an LED array. In this paper, we focus on the time-gradient and the space-gradient values in the captured images and draws both gradient value as a scatter diagram. This scatter diagram enables us to regard the LED acquisition as discriminant analysis. From the above, this paper proposes a new acquisition method and confirms its effectiveness by the experiment in a driving situation.

  150. Driver Assistant System using Visible Light Communications : Road-to-Vehicle Visible Light Communications using LED Array and On-Vehicle High-Speed Camera Reviewed

    YAMAZATO Takaya

    Technical report of IEICE. OCS   Vol. 113 ( 391 ) page: 17 - 23   2014.1

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We are conducting a study on viheicle-infrastractuctre cooperateive systems using visible light communications for driving safty applications. This paper introduces our studies on such VLC supported ITS systems using a high-speed image sensor as a VLC receiver equiped on a vehicle. The image sensors are now adopted for a lane keeping, an obstables recognition, a range estimation and many other applications. If we could add a VLC function to those safety applications, then a driver can recognize his environment visually and also he recognize his environment by signals transmitted through an LED traffic lights, LED tail lights, LED signage board, etc in a form of VLC signals. Together, it can contribute to more extensive safety driving.

    CiNii Article

  151. Driver Assistant System using Visible Light Communications : Road-to-Vehicle Visible Light Communications using LED Array and On-Vehicle High-Speed Camera Reviewed

    YAMAZATO Takaya

    IEICE technical report. Communication systems   Vol. 113 ( 390 ) page: 57 - 63   2014.1

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We are conducting a study on viheicle-infrastractuctre cooperateive systems using visible light communications for driving safty applications. This paper introduces our studies on such VLC supported ITS systems using a high-speed image sensor as a VLC receiver equiped on a vehicle. The image sensors are now adopted for a lane keeping, an obstables recognition, a range estimation and many other applications. If we could add a VLC function to those safety applications, then a driver can recognize his environment visually and also he recognize his environment by signals transmitted through an LED traffic lights, LED tail lights, LED signage board, etc in a form of VLC signals. Together, it can contribute to more extensive safety driving.

    CiNii Article

  152. Application of visible light communication to LED traffic light Reviewed

    T. Yamazato

    Journal of Light & Visual Environment (JLVE)   Vol. 98 ( no.1 ) page: pp.17-20   2014.1

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    Language:Japanese  

    Visible light communications (VLC) is the latest optical wireless communications technologies that uses low-power light emitting diodes, or LEDs, not only to provide light but also to broadcast data. LEDs are extremely energy-efficient and predicted to become widespread in general lighting application. Because LED is a solid-state lighting device, it can be modulated at high-speed compared with other lighting sources. VLC uses LEDs, which send data by flashing light at speeds undetectable to the human eye.Widespread use of LEDs in traffic applications and growing interest in Intelligent Transport System (ITS) presents an opportunity for VLC. Data transmission using LED traffic lights, LED road illumination, and LED brake lights are typical application.In this paper, an on-going research, road-to-vehicle visible light communication, will be introduced. The LED array, assumed to be an LED traffic light, is used as a transmitter and it sends data to a moving vehicle. By providing data together with a traffic signal that is visible to a driver, a safety driving support can be realized.Finally, the author suggests readers a glimpse of wealth on "dual use of LEDs" and concludes the paper.

  153. Driver Assistant System using Visible Light Communications Invited

    Takaya Yamazato

    IEICE Technical Report   Vol. CS2013-94   page: 57-63   2014.1

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    Authorship:Lead author   Language:Japanese  

    We are conducting a study on viheicle-infrastractuctre cooperateive systems using visible light commu- nications for driving safty applications. This paper introduces our studies on such VLC supported ITS systems using a high-speed image sensor as a VLC receiver equiped on a vehicle. The image sensors are now adopted for a lane keeping, an obstables recognition, a range estimation and many other applications. If we could add a VLC function to those safety applications, then a driver can recognize his environment visually and also he recognize his environment by signals transmitted through an LED traffic lights, LED tail lights, LED signage board, etc in a form of VLC signals. Together, it can contribute to more extensive safety driving.

  154. Multiple LED Arrays Acquisition for Image-Sensor-Based I2V-VLC Using Block Matching

    S. Arai, Y. Shiraki, T. Yamazato, H. Okada, T. Fujii, T. Yendo

    IEEE Consumer Communications and Networking Conference     page: 605-610   2014.1

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    Language:English  

    The present paper proposes a novel multiple-LED-arrays acquisition for an infrastructure-to-vehicle visible light communication (I2V-VLC) using LED arrays (transmitter) and an in-vehicle high-speed image sensor (receiver). In order to achieve a robust detection of LED arrays, we employ the block matching algorithm, which is a way of finding a corresponding position between two successive frames. The proposed method divides a captured image into a number of small domains (blocks) and determines if the LED array is present or absent using the block matching. We perform I2V-VLC experiments with multiple-LED arrays and evaluate the acquisition capability of the proposed method.

  155. M-ary Modulation Scheme Based on Separation of Deterministic Chaotic Dynamics for Noncoherent Chaos-Based Communications Reviewed

    S. Arai, Y. Nishio, T. Yamazato

    NOLTA, IEICE   Vol. 5 ( 2 ) page: 210 - 221   2014

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    The present paper proposes a novel M-ary modulation scheme based on separation and reconstruction of deterministic chaotic dynamics for noncoherent chaos-based communications. The M-ary modulation scheme can transmit b-bit data at a time by using M=2b distinct sequences. In order to generate M distinct sequences and recover b-bit data, the proposed system separates the chaotic dynamics having the chaotic sequence by using M interleavers, and reconstructs the original sequence based on the chaotic dynamics from the separated one by using M deinterleavers. In advance, each data symbol among M symbols is allocated to each interleaver-deinterleaver pair. The transmitter selects an interleaver corresponding to a data symbol and separates the order of samples of the chaotic sequence using the selected interleaver. The receiver feeds the received sequence into all M deinterleavers and outputs M reconstructed sequences. The proposed system can reconstruct the original chaotic sequence only when the correct deinterleaver, which becomes paired with the interleaver, is selected. Therefore, the receiver can recover b-bit data by analyzing the chaotic dynamics of each reconstructed sequence. We carry out computer simulations and evaluate performances of the proposed M-ary modulation scheme.

    DOI: 10.1587/nolta.5.210

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  156. BER Characteristic of Optical-OFDM using OCI Reviewed

    Yuki Goto, Isamu Takai, Takaya Yamazato, Hiraku Okada, Akitoshi Fujii, Shoji Kawahito, Shintaro Arai, Tomohiro Yendo, Koji Kamakura

    2014 IEEE ASIA PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS (APCCAS)   Vol. 2015-February ( February ) page: 328 - 331   2014

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    Light-emitting diode (LED) transmitters based optical wireless communication (OWC) systems offer the potential for new generation communication systems. Particularly, an image sensor based OWC systems consist of the LED transmitters and camera receivers are expected to contribute to intelligent transport system (ITS) for driving supports. For high achievable data rates, orthogonal frequency division multiplexing (OFDM) based OWC systems have attracted a great deal of attention. Despite attractive features of optical OFDM, only few attempts have so far been made to adopt it as a modulation scheme of an image sensor based OWC system. There remains a need for an evaluation of adopting an optical OFDM to the image sensor based OWC systems. Another important issue needs to be addressed is the performance degradation due to a frequency response of an actual image sensor device, especially a signal attenuation loss in higher frequency. In addition to such loss, a narrow band noise generated by its circuits also degrades the performance. The purpose of this paper is to investigate BER performances of the optical-OFDM using an actual image sensor device, the optical communication image sensor (OCI). From simulation results, it is found that the frequency response and the narrowband noise at 12MHz of the OCI lead to the significant reduction of BER performances. Additionally, the results shows that ACO-OFDM shows a little better performance compared to DCO-OFDM with the same bandwidth efficiency.

    DOI: 10.1109/APCCAS.2014.7032786

    Web of Science

    Scopus

  157. Channel Fluctuation Measurement for Image Sensor Based I2V-VLC, V2I-VLC, and V2V-VLC Reviewed

    Masayuki Kinoshita, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Shintaro Arai, Tomohiro Yendo, Koji Kamakura

    2014 IEEE ASIA PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS (APCCAS)   Vol. 2015-February ( February ) page: 332 - 335   2014

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    In image sensor based VLC, transmitter acquisition and tracking are critical issue. However, the fluctuation of the VLC transmitter in the image plane caused by vehicle movement, complicates correct data reception. Therefore, in this paper, we present results of channel fluctuation measurements for infrastructure-to-vehicle VLC (I2V-VLC), vehicle-to-infrastructure VLC (V2I-VLC), and vehicle-to-vehicle VLC (V2V-VLC). We analyze channel fluctuation in terms of optical flow from measured data.

    DOI: 10.1109/APCCAS.2014.7032787

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  158. Improving communication rate of visible light communication system using high-speed camera Reviewed

    Iwase Daigo, Kasai Makoto, Yendo Tomohiro, Arai Shintaro, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki

    2014 IEEE ASIA PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS (APCCAS)     page: 336 - 339   2014

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  159. Improving communication rate of visible light communication system using high-speed camera Reviewed

    Daigo Iwase, Makoto Kasai, Tomohiro Yendo, Shintaro Arai, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii

    2014 IEEE ASIA PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS (APCCAS)   Vol. 2015-February ( February ) page: 336 - 339   2014

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    We focus on the road-to-vehicle visible light communication that system is composed of LED matrix as transmitter and high-speed camera as receiver. Conventionally, the transmitting rate has been reduced to half of the frame rate of the camera, to avoid intersymbol interference because of exposure time of camera frame. We propose a method to improve the communication rate. The transmitting rate is set same to receiver's frame rate, and the sent data is estimated from pattern mixed image. Using 8b/10b encoding instead of conventional reversal pattern to reduce the flickering of transmitter's lighting is also proposed.

    DOI: 10.1109/APCCAS.2014.7032788

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  160. Motion Modeling of Mobile Transmitter for Image Sensor Based I2V-VLC, V2I-VLC, and V2V-VLC Reviewed

    Kinoshita Masayuki, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Arai Shintaro, Yendo Tomohiro, Kamakura Koji

    2014 GLOBECOM WORKSHOPS (GC WKSHPS)     page: 450 - 455   2014

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  161. Multiple LED Arrays Acquisition for Image-Sensor-Based I2V-VLC Using Block Matching Reviewed

    Shintaro Arai, Yasutaka Shiraki, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Tomohiro Yendo

    2014 IEEE 11TH CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE (CCNC)     page: 605 - 610   2014

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    The present paper proposes a novel multiple-LED-arrays acquisition for an infrastructure-to-vehicle visible light communication (I2V-VLC) using LED arrays (transmitter) and an in-vehicle high-speed image sensor (receiver). In order to achieve a robust detection of LED arrays, we employ the block matching algorithm, which is a way of finding a corresponding position between two successive frames. The proposed method divides a captured image into a number of small domains (blocks) and determines if the LED array is present or absent using the block matching. We perform I2V-VLC experiments with multiple-LED arrays and evaluate the acquisition capability of the proposed method.

    DOI: 10.1109/CCNC.2014.6866634

    Web of Science

    Scopus

  162. Multiple LED Arrays Acquisition for Image-Sensor-Based I2V-VLC Using Block Matching Reviewed

    Arai Shintaro, Shiraki Yasutaka, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Yendo Tomohiro

    2014 IEEE 11TH CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE (CCNC)     2014

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  163. Motion Modeling of Mobile Transmitter for Image Sensor Based I2V-VLC, V2I-VLC, and V2V-VLC Reviewed

    Masayuki Kinoshita, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Shintaro Arai, Tomohiro Yendo, Koji Kamakura

    2014 GLOBECOM WORKSHOPS (GC WKSHPS)     page: 450 - 455   2014

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    Visible light communication (VLC) using light-emitting diodes (LEDs) is drawing much attention. There are two types of VLC reception devices, a photodiode and an image sensor. VLC using image sensor is called image sensor based VLC. As the receiver only uses the image sensor pixels that sense LED transmission sources and discards other pixels, including those sensing noise sources, image sensor based VLC is an attractive solution for outdoor mobile applications. However, little evidence is available for channel modeling of image sensor based VLC in mobile outdoor environments, especially for motion modeling of VLC transmitter. In this paper, we propose a motion model of VLC transmitter. In particular, we consider three cases; infrastructure-to-vehicle VLC (I2V-VLC), vehicle-to-infrastructure VLC (V2I-VLC), and vehicle-to-vehicle VLC (V2V-VLC). As a result, we show that the motion model of the VLC transmitter on the captured image for the three aforementioned situations (i.e., I2V-VLC, V2I-VLC, and V2V-VLC) can be expressed in the identical pinhole camera model.

    DOI: 10.1109/GLOCOMW.2014.7063473

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  164. Spatially-Modulated Space-Time Coding in Visible Light Communications Using 2 x 2 LED Array Reviewed

    Ebihara Katsunori, Kamakura Koji, Yamazato Takaya

    2014 IEEE ASIA PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS (APCCAS)     page: 320 - 323   2014

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  165. Spatially-Modulated Space-Time Coding in Visible Light Communications Using 2 x 2 LED Array Reviewed

    Katsunori Ebihara, Koji Kamakura, Takaya Yamazato

    2014 IEEE ASIA PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS (APCCAS)   Vol. 2015-February ( February ) page: 320 - 323   2014

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    This paper demonstrates the feasibility of binary spatially-modulated space-time (SM-ST) coding in an outdoor image-sensor-based visible light communication (VLC) system. We showed that at the transmission distance where intensity modulated symbols from two different light emitting diodes (LEDs) are detected at one pixel of the image plane of the image sensor, space time (ST) coding enables to decouple the two symbols and to extend error-free transmission distance. We furthermore aim at increasing transmission rate per symbol duration when the spatial resolution is improved when the receiver approaches the LED array of the transmitter, by superimposing space shift keying (SSK) signal with the diagonal and anti-diagonal set of the 2 x 2 matrix onto the LED patterns. We built an experimental testbed with LEDs modulated at 1 kbps and a high-speed camera operating at 1,000 fps. Our experimental results validate that SM-ST coding achieves 30m of the error-free transmission distance for the additional bit based on SSK, without deteriorating the reception quality and range of the space-time coded bits.

    DOI: 10.1109/APCCAS.2014.7032784

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  166. Application of Visible Light Communication to LED Traffic Light(<Special Issue>For the Further Spread of SSL and the Expansion of the Application Field) Reviewed

    Yamazato Takaya

    JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN   Vol. 98 ( 1 ) page: 17 - 20   2014

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    Publishing type:Research paper (scientific journal)   Publisher:The Illuminating Engineering Institute of Japan  

    Visible light communications (VLC) is the latest optical wireless communications technology that uses low-power light emitting diodes, or LEDs, not only to provide light but also to broadcast data. LEDs are extremely energy-efficient and predicted to become widespread in general lighting application. Because LED is a solid-state lighting device, it can be modulated at high-speed compared with other lighting sources. VLC uses LEDs, which send data by flashing light at speeds undetectable to the human eye. Widespread use of LEDs in traffic applications and growing interest in Intelligent Transport System (ITS) presents an opportunity for VLC. Data transmission using LED traffic lights, LED road illumination, and LED brake lights are typical application. In this paper, an on-going research, road-to-vehicle visible light communication, will be introduced. The LED array, assumed to be an LED traffic light, is used as a transmitter and it sends data to a moving vehicle. By providing data together with a traffic signal that is visible to a driver, a safety driving support can be realized. Finally, the author suggests readers a glimpse of wealth on "dual use of LEDs" and concludes the paper.

    DOI: 10.2150/jieij.98.17

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  167. A Study on Simple LED-VLC Flashlight Transmitter for Disaster Situation Reviewed

    K. Miyazaki, Y. Ohira, S. Arai, T. Yendo, T. Yamazato, H. Okada, T. Fujii

    Proceedings of 2013 IEEE Workshop on Nonlinear Circuit Networks (NCN'13)     page: -   2013.12

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    This study focuses on the visible light communication(VLC) system using LED and a high-speed camera inorder to develop robust and adaptable communication systemsin the disaster situation, such as an earthquake. Especially, we consider utilization of a flashlight, which is often used in disaster situations, as a transmitter. We develop a simple LED-VLC transmitter using a flashlight and perform a communication experiment using it.

  168. Accuracy Improvement by Phase Only Correlation for Distance Estimation Scheme for Visible Light Communications Using an LED Array and a High-speed Camera Reviewed

    A. Ohmura, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

    IEICE Transaction on Communications   Vol. J96-B ( no.12 ) page: pp.1365-1368   2013.12

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    In this paper, we focus on a distance estimation scheme in road to vehicle communicationsystem. We use LED transmitter and high-speed camera. The accuracy of camera based scheme is governedby the size of pixel. Therefore we introduce phase only correlation (POC) to estimate with high accuracy.

  169. Accuracy Improvement by Phase Only Correlation for Distance Estimation Scheme for Visible Light Communications Using an LED Array and a High-speed Camera Reviewed

    A. Ohmura, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

    IEICE Transaction on Communications   Vol. J96-B ( 12 ) page: 1365-1368   2013.12

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  170. Accuracy Improvement by POC for Distance Estimation Scheme for VLC Using an LED Array and a High-Speed Camera Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, ARAI Shintaro, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    The transactions of the Institute of Electronics, Information and Communication Engineers. B   Vol. 96 ( 12 ) page: 1365 - 1368   2013.12

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  171. [Invited Talk] SN, USN, and then ASN Invited

    T. Yamazato

    IEICE Technical Report   ( ASN2013-112 ) page: pp.121-124   2013.11

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  172. Invited Talk : SN, USN, and then ASN Reviewed

    YAMAZATO Takaya

    IEICE technical report. ASN, Ambient intelligence and sensor networks   Vol. 113 ( 328 ) page: 121 - 124   2013.11

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    Technical Committees (TCs) on Ad Hoc Networks (AN) and Ubiquitous and Sensor Networks (USN) have been consolidated in new TC, Ambient Intelligence and Sensor Networks (ASN). USN was the result of integrating two TCs in different societies, Ubiquitous and Real-World Oriented Networking (URON) in Communication Society and Sensor Networks (SN) in Engineering Science Society. The author has been engaged in SN, USN, and ASN. The present article looks back the aims and backgrounds of those TCs. In expectation of the further advancement of ASN, a few concluding remarks are presented.

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  173. Image Sensor based Visible Light Communication for Automotive Applications Reviewed

    T. Yamazato, I. Takai, H. Okada, T. Fujii, T. Yendo, S. Arai, M. Andoh, K. Yasutomi, K. Kagawa, S. Kawahito

    Proc. of International Symposium on Optical Wireless Communications     page: -   2013.11

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    This talk introduces visible light communication (VLC) for automotive applications using an image sensor. In particular, vehicle-to-infrastructure visible light communication (V2I-VLC) and vehicle-to-vehicle visible light communication (V2V-VLC) are presented. Previous studies have documented the effectiveness of V2I and V2V communication using radio technology for improving automotive safety. In this talk, I identify characteristics unique to the introduced image sensor based VLC as compared to radio wave technology. The advantages of VCL are twofold: the line-of-sight feature of visible light links and an image sensor that provides not only the VLC function but also vehicle safety applications using image and video processing. We present two on-going image sensors based V2I-VLC and V2V-VLC projects.

  174. Performance Evaluation of Error-Correcting Scheme Using Separation of Chaotic Dynamics for Number of Transmitting Data

    S. Arai, Y. Nishio and T. Yamazato

    IEICE Technical Report   ( NLP2013-108 ) page: pp. 205-209   2013.10

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    Noncoherent chaos communications, which do not need to use basis signals (unmodulated carriers) for demodulation, are unique communication systems using characteristics of chaos. However, the communication performance of the noncoherent system is lower as compared with the standard communication systems. Thus, it is important to advance noncoherent system in order to improve its performance. In our previous research, we have proposed a novel error-correcting method using a separation and reconstruction of the chaotic dynamics, which is one of characteristics of chaos. As simulation results, we have confirmed that the advantage gained in BER performance of our error-correcting method is about 2--2.5 dB compared to the conventional one (w/o coding). This paper focuses on a number of transmitting data and a combination of symbols, and analyzes an error-correcting capability for evaluating advantages of the separation and reconstruction of the chaotic dynamics in detail.

  175. Performance evaluation of the weak signal detection of the Stochastic Resonance Receiver using Schmitt Trigger

    K.Chiga, H.Tanaka, T.Yamazato, Y.tadokoro, S.Arai

    IEICE Technical Report   ( NLP2013-73 ) page: pp.19-23   2013.10

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    Stochastic Resonance(SR) is a nonlinear phenomena in which the Signal-to-Noise Ratio(SNR) is enhanced by an increase of the noise. By using SR, we can detect the weak signal which cannot detect by the conventional receiver. In this paper, we consider the application of SR to the communication systems. we implement the Stochastic Resonance Receiver using Schmitt Trigger as the Stochastic Resonance system. We evaluate the performance of the weak signal responce and we discuss about the weak signal detection.

  176. Performance evaluation of the weak signal detection of the Stochastic Resonance Receiver using Schmitt Trigger Reviewed

    CHIGA Keita, TANAKA Hiroya, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    IEICE technical report. Nonlinear problems   Vol. 113 ( 271 ) page: 19 - 23   2013.10

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    Stochastic Resonance(SR) is a nonlinear phenomena in which the Signal-to-Noise Ratio(SNR) is enhanced by an increase of the noise. By using SR, we can detect the weak signal which cannot detect by the conventional receiver. In this paper, we consider the application of SR to the communication systems. we implement the Stochastic Resonance Receiver using Schmitt Trigger as the Stochastic Resonance system. We evaluate the performance of the weak signal responce and we discuss about the weak signal detection.

    CiNii Article

  177. Performance Evaluation of Error-Correcting Scheme Using Separation of Chaotic Dynamics for Number of Transmitting Data Reviewed

    ARAI Shintaro, NISHIO Yoshifumi, YAMAZATO Takaya

    IEICE technical report. Nonlinear problems   Vol. 113 ( 271 ) page: 205 - 209   2013.10

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Noncoherent chaos communications, which do not need to use basis signals (unmodulated carriers) for demodulation, are unique communication systems using characteristics of chaos. However, the communication performance of the noncoherent system is lower as compared with the standard communication systems. Thus, it is important to advance noncoherent system in order to improve its performance. In our previous research, we have proposed a novel error-correcting method using a separation and reconstruction of the chaotic dynamics, which is one of characteristics of chaos. As simulation results, we have confirmed that the advantage gained in BER performance of our error-correcting method is about 2--2.5 dB compared to the conventional one (w/o coding). This paper focuses on a number of transmitting data and a combination of symbols, and analyzes an error-correcting capability for evaluating advantages of the separation and reconstruction of the chaotic dynamics in detail.

    CiNii Article

  178. Utilization of Spatio-temporal image for LED array acquisition in Road to Vehicle Visible Light Communication Reviewed

    S.Usui, T.Yamazato, S.Arai, T.Yendo, T.Fujii, H.Okada

    20th World Congress on Intelligent Transport Systems     page: -   2013.10

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    In this paper, we focus attention on visible light communication systems using an LED array as a transmitter and a high-speed camera as a receiver for road-to-vehicle communications (R2V-VLC) in intelligent transport systems. To implement R2V-VLC, it is necessary for the receiver to search the target LED array from the captured images (LED array acquisition) before data demodulation. We propose a new approach for LED array acquisition. We focus on spatio-temporal image and spatio-temporal cross-section image and show LED array in the spatio-temporal image has high time-gradient value and low space-gradient value. Using such characteristic gradient values, we propose new LED array acquisition method. As the results of the experiment in driving situation, we can achieve acquisition miss rate = 0%.

  179. Accuracy Improvement by Phase Only Correlation for Distance Estimation Scheme for Visible Light Communications Using an LED Array and a High-speed Camera Reviewed

    A. Ohmura, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

    20th World Congress on Intelligent Transport Systems     page: -   2013.10

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    In this paper, we focus on a distance estimation scheme using camera. Our distance estimation scheme is based on triangulation. The accuracy of camera based scheme is governed by resolution of a camera, or equivalently the size of pixel. Therefore we introduce phase only correlation (POC) to estimate with subpixel accuracy. As a result of experiment, we will show that our scheme achieves less than 0.3m estimation error at the distance of 60m. By using POC, the resolution of estimation reaches nearly 0.02 pixel, much less than one pixel.

  180. A Study on Implementation of Stochastic Resonance Receiver using Schmitt Trigger

    K. Chiga, H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai

    IEICE Society Conference   ( A-2-13 ) page: p.32   2013.9

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  181. The outline of I-Scover (IEICE Knowledge Discovery)

    T. Yamazato

    IEICE Society Conference     page: -   2013.9

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  182. A Study on the Signal Sensitivity of Stochastic Resonance Receiver for the Subthreshold Bi-Polar Pulse Detection

    H. Tanaka, K. Chiga, T. Yamazato, Y. Tadokoro, S. Arai

    Enginnering Sciences Society Conference of IEICE   ( A-2-14 ) page: p. 33   2013.9

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  183. Implementation of Bi-Polar Pulse SR Receiver Using Schmitt Trigger and Evaluation of its Performance Reviewed

    K.Chiga, H.Tanaka, T.Yamazato, Y.Tadokoro, S.Arai

    2013 International Symposium on Nonlinear Theory and its Application(NOLTA 2013)     page: -   2013.9

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    We consider an application of Stochastic Resonance to wireless communication system. Stochastic Resonance (SR) is well known as a phenomenon in which weak signal in nonlinear system can be detected by added noise. A receiver using Stochastic Resonance (SR Receiver) can detect a weak signal which is not detectable in the conventional receiver. In this paper, we consider the implementation of bi-polar pulse SR Receiver using Schmitt Trigger and evaluate the performance in Signal-to-Noise Ratio (SNR) and Bit Error Rate (BER).

  184. [Invited Talk] Application of visible light communication to LED traffic light

    T. Yamazato

    Proceeding of 2013 Annual Conference of IEIJ     page: -   2013.9

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  185. A Study on Implementation of Stochastic Resonance Receiver using Schmitt Trigger Reviewed

    CHIGA Keita, TANAKA Hiroya, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the Society Conference of IEICE   Vol. 2013   2013.9

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  186. A Study on the Signal Sensitivity of Stochastic Resonance Receiver for the Subthreshold Bi-Polar Pulse Detection Reviewed

    TANAKA Hiroya, CHIGA Keita, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the Society Conference of IEICE   Vol. 2013   2013.9

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  187. Let's Search IEICE Contents through New Meta-Data System I-Scover!

    T. Yamazato

    IEICE Global Plaza   Vol. No.55   page: -   2013.8

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    IEICE launched the new metadata search system called "I-Scover" on April 3, 2013. For the time being, I-Scover provides the metadata search service of all papers published in IEICE transactions covering from the first edition published in 1968 up to the present edition, Technical Reports (from 2006) and international conference papers of ISPA and EMC. The total number of searchable contents reaches 150,000. This article briefly introduces I-Scover. Before going to the details, let me start with a quiz. What phrase do you guess if you say "I-Scover" for three times?

  188. Lectures in Nagoya University OCW that providing play and learning experiences Reviewed

    T. Yamazato

    2013 JSEE Annual Conference     page: -   2013.8

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  189. M-ary Modulation Method Using Separation of Chaotic Dynamics for Noncoherent Chaos Communications

    S. Arai, Y. Nishio and T. Yamazato

    The 26th Workshop on Circuits and Systems     page: -   2013.7

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  190. Distance Estimation Scheme for Integrated V2I-VLC Simulating the Vibration of Driving Vehicle

    A.OHMURA, T.YAMAZATO, H.OKADA, T. FUJII, T. YENDO, S. ARAI

    Technical Report of IEICE   ( ASN2013-55 ) page: pp.41-46   2013.7

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    In road-to-vehicle visible light communication data is transmitted toward moving vehicles from theLED array installed on roads. Robust data reception and fast communication are possible by using a high-speedcamera as it can reduce the vibration of vehicles. In this road-to-vehicle visible light communication, we proposean integrated system of communication and distance estimation by sending a known data pattern from the LEDarray. On issues which is distance estimation performance deterioration by the vibration of the running vehicle, tryto resolve them using the technique using the phase-only correlation method.

  191. LED array acquisition method based on Spatio-temporal image in Road to Vehicle Visible Light Communication

    S.Usui, T.Yamazato, S.Arai, T.Yendo, T.Fujii, H.Okada

    Technical Report of IEICE   ( ASN2013-55 ) page: pp.47-52   2013.7

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    In this paper, we focus attention on road-to-vehicle visible light communication(R2V-VLC) in intelligent transport systems. This system uses an LED array as a transmitter and a high-speed camera as a receiver. To implement R2V-VLC, it is necessary to acquire the target LED array from the captured images at receiver before data demodulation. To achieve accurate aquisition, we analyze LED array by use of Spatio-temporal image. As the result of the analysis, we show the LED array in the spatio-temporal image has high time-gradient value and low space-gradient value. After that we propose a new LED array acquisition method using such characteristic gradient values.

  192. LED array acquisition method based on Spatio-temporal image in Road to Vehicle Visible Light Communication Reviewed

    USUI Syunsuke, YAMAZATO Takaya, ARAI Shintaro, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report   Vol. 113 ( 129 ) page: 19 - 24   2013.7

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    In this paper, we focus attention on road-to-vehicle visible light communication(R2V-VLC) in intelligent transport systems. This system uses an LED array as a transmitter and a high-speed camera as a receiver. To implement R2V-VLC, it is necessary to acquire the target LED array from the captured images at receiver before data demodulation. To achieve accurate acquisition, we analyze LED array by use of Spatio-temporal image. As the result of the analysis, we show the LED array in the spatio-temporal image has high time-gradient value and low space-gradient value. After that we propose a new LED array acquisition method using such characteristic gradient values.

    CiNii Article

  193. Distance Estimation Scheme for Integrated V2I-VLC Simulating the Vibration of Driving Vehicle Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    IEICE technical report   Vol. 113 ( 129 ) page: 13 - 17   2013.7

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    In road-to-vehicle visible light communication data is transmitted toward moving vehicles from the LED array installed on roads. Robust data reception and fast communication are possible by using a high-speed camera as it can reduce the vibration of vehicles. In this road-to-vehicle visible light communication, we propose an integrated system of communication and distance estimation by sending a known data pattern from the LED array. On issues which is distance estimation performance deterioration by the vibration of the running vehicle, try to resolve them using the technique using the phase-only correlation method.

    CiNii Article

  194. LED array acquisition method based on Spatio-temporal image in Road to Vehicle Visible Light Communication Reviewed

    USUI Syunsuke, YAMAZATO Takaya, ARAI Shintaro, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report   Vol. 113 ( 131 ) page: 27 - 32   2013.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we focus attention on road-to-vehicle visible light communication(R2V-VLC) in intelligent transport systems. This system uses an LED array as a transmitter and a high-speed camera as a receiver. To implement R2V-VLC, it is necessary to acquire the target LED array from the captured images at receiver before data demodulation. To achieve accurate acquisition, we analyze LED array by use of Spatio-temporal image. As the result of the analysis, we show the LED array in the spatio-temporal image has high time-gradient value and low space-gradient value. After that we propose a new LED array acquisition method using such characteristic gradient values.

    CiNii Article

  195. Distance Estimation Scheme for Integrated V2I-VLC Simulating the Vibration of Driving Vehicle Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    IEICE technical report. ASN, Ambient intelligence and sensor networks   Vol. 113 ( 132 ) page: 41 - 45   2013.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In road-to-vehicle visible light communication data is transmitted toward moving vehicles from the LED array installed on roads. Robust data reception and fast communication are possible by using a high-speed camera as it can reduce the vibration of vehicles. In this road-to-vehicle visible light communication, we propose an integrated system of communication and distance estimation by sending a known data pattern from the LED array. On issues which is distance estimation performance deterioration by the vibration of the running vehicle, try to resolve them using the technique using the phase-only correlation method.

    CiNii Article

  196. Distance Estimation Scheme for Integrated V2I-VLC Simulating the Vibration of Driving Vehicle Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    Technical report of IEICE. RCS   Vol. 113 ( 130 ) page: 55 - 59   2013.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In road-to-vehicle visible light communication data is transmitted toward moving vehicles from the LED array installed on roads. Robust data reception and fast communication are possible by using a high-speed camera as it can reduce the vibration of vehicles. In this road-to-vehicle visible light communication, we propose an integrated system of communication and distance estimation by sending a known data pattern from the LED array. On issues which is distance estimation performance deterioration by the vibration of the running vehicle, try to resolve them using the technique using the phase-only correlation method.

    CiNii Article

  197. Distance Estimation Scheme for Integrated V2I-VLC Simulating the Vibration of Driving Vehicle Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    IEICE technical report   Vol. 113 ( 131 ) page: 21 - 25   2013.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In road-to-vehicle visible light communication data is transmitted toward moving vehicles from the LED array installed on roads. Robust data reception and fast communication are possible by using a high-speed camera as it can reduce the vibration of vehicles. In this road-to-vehicle visible light communication, we propose an integrated system of communication and distance estimation by sending a known data pattern from the LED array. On issues which is distance estimation performance deterioration by the vibration of the running vehicle, try to resolve them using the technique using the phase-only correlation method.

    CiNii Article

  198. LED array acquisition method based on Spatio-temporal image in Road to Vehicle Visible Light Communication Reviewed

    USUI Syunsuke, YAMAZATO Takaya, ARAI Shintaro, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report. ASN, Ambient intelligence and sensor networks   Vol. 113 ( 132 ) page: 47 - 52   2013.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we focus attention on road-to-vehicle visible light communication(R2V-VLC) in intelligent transport systems. This system uses an LED array as a transmitter and a high-speed camera as a receiver. To implement R2V-VLC, it is necessary to acquire the target LED array from the captured images at receiver before data demodulation. To achieve accurate acquisition, we analyze LED array by use of Spatio-temporal image. As the result of the analysis, we show the LED array in the spatio-temporal image has high time-gradient value and low space-gradient value. After that we propose a new LED array acquisition method using such characteristic gradient values.

    CiNii Article

  199. LED array acquisition method based on Spatio-temporal image in Road to Vehicle Visible Light Communication Reviewed

    USUI Syunsuke, YAMAZATO Takaya, ARAI Shintaro, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    Technical report of IEICE. RCS   Vol. 113 ( 130 ) page: 61 - 66   2013.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we focus attention on road-to-vehicle visible light communication(R2V-VLC) in intelligent transport systems. This system uses an LED array as a transmitter and a high-speed camera as a receiver. To implement R2V-VLC, it is necessary to acquire the target LED array from the captured images at receiver before data demodulation. To achieve accurate acquisition, we analyze LED array by use of Spatio-temporal image. As the result of the analysis, we show the LED array in the spatio-temporal image has high time-gradient value and low space-gradient value. After that we propose a new LED array acquisition method using such characteristic gradient values.

    CiNii Article

  200. Performance Evaluation of Stochastic Resonance Receiver for the Multi Carrier Detection Reviewed

    H. Tanaka, K. chiga, T. Yamazato, Y, Tadokoro, S. Arai

    NANOENERGY2013   ( pp.58-59 ) page: -   2013.7

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    Stochastic Resonance (SR), known as a noise-enhanced phenomenon, can improve the performance of communication systems. By applying SR in the receiver, it is possible to detect a weak signal that is not detectable in the traditional linear receiver. In the SR systems, the input of multi-carrier has not ever been discussed. So this paper proposes the SR receiver for multi-carrier detection and evaluates its Bit-Error-Rate (BER) performance.

  201. Discover IEICE Contents Using I-Scover

    T. Yamazato

      Vol. 37   page: -   2013.6

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    The IEICE launched new metadata search system called I-Scover (http://i-scover.ieice.org) from April 3rd, 2013. I-Scover provides metadata search of the IEICE transactions papers (from its first edition published in 1968), Technical Reports (from 2006) and international conference papers of ISPA and EMC. The total of the contents that can be searched is more than 150,000.This article briefly introduces I-Scover. Before going to detail, let me start with a quiz. What phrase do you guess if you say I-Scover for three times?

  202. The outline of I-Scover

    T. Yamazato

    IEICE General Conference     page: -   2013.3

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  203. Input-output phase difference performance of Stochastic Resonance Schmitt Trigger receiver

    K. Chiga, H. Tanaka, T. Yamazato, Y.Tadokoro, S. Arai

    IEICE General Conference   ( A-2-11 ) page: p.38   2013.3

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  204. Intensity Estimation Method of LED Array for Visible Light Communication Reviewed

    T. Ito, T. Yendo, S. Arai, T. Yamazato, H. Okada, T. Fujii

    Proc. SPIE 8663, Video Surveillance and Transportation Imaging Applications     2013.3

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    This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic light as the transmitter and camera as the receiver. The traffic light is composed of a hundred of LEDs on two dimensional plain. In this system, data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually, and they are received as images by the camera. Here, there are problems that neighboring LEDs on the received image are merged due to less number of pixels in case that the receiver is distant from the transmitter, and/or due to blurring by defocus of the camera. Because of that, bit error rate (BER) increases due to recognition error of intensity of LEDs To solve the problem, we propose a method that estimates the intensity of LEDs by solving the inverse problem of communication channel characteristic from the transmitter to the receiver. The proposed method is evaluated by BER characteristics which are obtained by computer simulation and experiments. In the result, the proposed method can estimate with better accuracy than the conventional methods, especially in case that the received image is blurred a lot, and the number of pixels is small. &copy; (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

    DOI: doi:10.1117/12.2005738

  205. A performance analysis of the stochastic resonance receiver for the subthreshold bi-polar pulse detection

    H. Tanaka, K. Chiga, T. Yamazato, Y. Tadokoro, S. Arai

    IEICE General Conference   ( A-2-13 ) page: p.40   2013.3

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  206. A-2-11 Input-output phase difference performance of Stochastic Resonance Schmitt Trigger receiver Reviewed

    CHIGA Keita, TANAKA Hiroya, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the IEICE General Conference   Vol. 2013   2013.3

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  207. A-2-13 A performance analysis of the stochastic resonance receiver for the subthreshold bi-polar pulse detection Reviewed

    TANAKA Hiroya, CHIGA Keita, YAMAZATO Takaya, TADOKORO Yukihiro, ARAI Shintaro

    Proceedings of the IEICE General Conference   Vol. 2013   2013.3

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  208. Performance Analysis of Error-Correcting Method Using Separation of Chaos for Noncoherent Chaos Communications Reviewed

    S. Arai, Y. Nishio and T. Yamazato

    Proceedings of RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP'13)     page: pp. 225-228   2013.3

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    This paper analyzes the performance of the error-correcting method, which was proposed in the previous research, using the separation and the reconstruction of chaos for noncoherent chaos communications. Especially, we focus on a number of transmitting data and a combination of symbols (i.e., data pattern). We consider that the capability of the error correction depends on the number of data and the data pattern because the proposed method performs the error correction using successive data symbols. This study performs simulations for the number of data and the data pattern, and evaluates BER performance of the proposed method.

  209. Development of Simple Simulator for Visible Light Communication Using LED and Camera Reviewed

    T. Fukumoto, S. Arai, T. Yendo, T. Yamazato, H. Okada and T. Fujii

    Proceedings of RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP'13)     page: pp. 33-36   2013.3

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    This paper develops a simple simulator for the visible light communication (VLC) system using a LED traffic light and a camera for intelligent transport systems (ITS). We use image processing techniques for simulating effects of optical spatial channel which is a unique channel in VLC. We describe a system model of the VLC simulator and perform the simulation with various parameters of the image processing.

  210. Performance Evaluation of Stochastic Resonance Bi-Polar Pulse receiver Using Schmitt Trigger

    Keita CHIGA, Hiroya TANAKA, Takaya YAMAZATO, Yukihiro TADOKORO, Shintaro ARAI

    IEICE Complex Communication Sciences   ( CCS-2012-038 ) page: -   2013.3

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    We consider an application of Stochastic Resonance to wireless communication system. Stochastic Resonance(SR) is well known as a phenomenon in which weak signal in nonlinear system can be detected by added noise. A receiver using Stochastic Resonance(SR Receiver) can detect a weak signal which is not detectable in the conventional receiver. In this paper, we consider the implementation of Bi-Polar Pulse SR Receiver using Schmitt Trigger and the evaluation of the performance in Signal-to-Noise Ratio(SNR) and Bit Error Rate(BER).

  211. A bit-error-rate analysis on the stochastic resonance receiver for the weak bi-polar pulse

    Hiroya TANAKA, Keita CHIGA, Takaya YAMAZATO, Yukihiro TADOKORO, Shintaro ARAI

    IEICE Complex Communication Sciences   ( CCS-2012-039 ) page: -   2013.3

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    Stochastic resonance has an effect of improving the detection by increasing noise in the system. By applying this stochastic resonance in the receiver, it is possible to detect the subthreshold signal which is not detectable in the traditional linear receiver. This paper proposes an analysis method of the stochastic resonance receiver for the detection of the bi-polar pulse, which has good compatibility to stochastic resonance, and evaluates its bit-error-rate performance. And, the optimal noise power which maximizes the effect of stochastic resonance is discussed.

  212. Overlay Coding of Long Range Data and Short Range Data for Road-to-Vehicle Visible Light Communication Using LED Array and High-Speed Camera Reviewed

    S. Nishimoto, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

    IEICE Transactions on Communications   Vol. J96-B ( no.2 ) page: pp.191-201   2013.2

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  213. Overlay Coding of Long Range Data and Short Range Data for Road-to-Vehicle Visible Light Communication Using LED Array and High-Speed Camera Reviewed

    NISHIMOTO Sayaka, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    The transactions of the Institute of Electronics, Information and Communication Engineers. B   Vol. 96 ( 2 ) page: 191 - 201   2013.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  214. Interpixel Interference Cancellation Method for Road-to-Vehicle Visible Light Communication Reviewed

    Tatsuya Kasashima, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Tomohiro Yendo, Shintaro Arai

    2013 IEEE 5TH INTERNATIONAL SYMPOSIUM ON WIRELESS VEHICULAR COMMUNICATIONS (WIVEC)     page: 1 - 5   2013

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This paper aims to improve the transmission distance for the road-to-vehicle visible light communication system (R2V-VLC) using LED array and high-speed camera by reducing interference caused at the receiver. As we can transmit multiple data using LED array and high-speed camera, parallel data transmission can be possible. However, due to the diffusion of LED and the finiteness of the pixel size of image sensor, the focused LED will affect not only the actual corresponding pixel but also its surrounding pixels. We call this phenomenon as "interpixel interference (IPI)" and it causes degradation in error rate performance. To mitigate the IPI, we propose IPI cancellation scheme for the R2V-VLC system. As the results of the experiment, we can extend the error-free distance from 40m to 60m by the IPI cancellation.

    DOI: 10.1109/wivec.2013.6698237

    Web of Science

    Scopus

  215. Channel information estimation for error correcting code in road-to-vehicle visible light communication systems Reviewed

    Hiraku Okada, Shinnosuke Misawa, Takaya Yamazato, Toshiaki Fujii, Tomohiro Yendo

    2013 IEEE 5th International Symposium on Wireless Vehicular Communications, WiVeC 2013 - Proceedings     page: 1 - 5   2013

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE Computer Society  

    This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic lights and high-speed cameras on cars. So as to improve the transmission reliability, an error correcting code like a low-density parity-check (LDPC) is applied to the road-to-vehicle VLC system. The decoder of the LDPC code needs channel information in order to maximize decoding performance. Usually, it is calculated from a signal-to-noise ratio (SNR) or bit error rate (BER) of a channel, where noise is a dominant factor of the channel characteristic. In the road-to-vehicle VLC system, not noise but interference among LEDs decides the channel characteristic. In this paper, we propose a channel information estimation method for the road-to-vehicle VLC system. The proposed method estimates a signal-to-interference ratio (SIR) from the receiving image, and calculates the channel information using the SIR. The proposed method is evaluated by experiment. As a result, the proposed method can achieve almost the same performance with the optimum case, and then maximize the decoding performance. © 2013 IEEE.

    DOI: 10.1109/wivec.2013.6698229

    Scopus

  216. 3-215 Lectures in Nagoya University OCW that providing play and learning experiences Reviewed

    Yamazato Takaya

    Proceedings of Annual Conference of Japanese Society for Engineering Education   Vol. 2013 ( 0 ) page: 268-269   2013

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    DOI: 10.20549/jseeja.2013.0_268

    CiNii Article

  217. Accuracy improvement by phase only correlation for distance estimation scheme for visible light communications using an LED array and a high-speed camera Reviewed

    Ohmura A.

    20th ITS World Congress Tokyo 2013     2013

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    Publishing type:Research paper (scientific journal)   Publisher:20th ITS World Congress Tokyo 2013  

    Scopus

  218. Alamouti-Type Coding for Visible Light Communication Based on Direct Detection Using Image Sensor Reviewed

    Yuta Amano, Koji Kamakura, Takaya Yamazato

    2013 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM)     page: 2430 - 2435   2013

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This paper proposes Alamouti-type space time (ST) coding to visible light communication (VLC) using light emitting diodes (LEDs) and image sensor-based direct detection with a high-speed camera. Although multiple LEDs of an array are used as transmitters to communicate to individual pixel elements of an image sensor which act as multiple receive elements, the received signal is essentially the image of the transmitting element, whose size in pixel reduces with distance. When the receiver captures the LED array at a distance where images of two neighboring LEDs in the array are not separated at the image plane, such distortion depreciates the symbol decision quality. Our proposed scheme aims at expanding the communication range limited by the pixel resolution of image sensor. Our implemented prototype demonstrates that ST coding is feasible to achieve 48-meter error-free transmission range while the repetition transmission achieves 26-m error-free range.

    DOI: 10.1109/GLOCOM.2013.6831438

    Web of Science

    Scopus

  219. Channel Information Estimation for Error Correcting Code in Road-to-Vehicle Visible Light Communication Systems Reviewed

    Okada Hiraku, Misawa Shinnosuke, Yamazato Takaya, Fujii Toshiaki, Yendo Tomohiro

    2013 IEEE 5TH INTERNATIONAL SYMPOSIUM ON WIRELESS VEHICULAR COMMUNICATIONS (WIVEC)     2013

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    Web of Science

  220. Alamouti-Type Coding for Visible Light Communication Based on Direct Detection Using Image Sensor Reviewed

    Amano Yuta, Kamakura Koji, Yamazato Takaya

    2013 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM)     page: 2430 - 2435   2013

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    Web of Science

  221. Intensity estimation method of LED array for visible light communication Reviewed

    Takanori Ito, Tomohiro Yendo, Shintaro Arai, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii

    Proceedings of SPIE - The International Society for Optical Engineering   Vol. 8663   2013

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    Language:English   Publishing type:Research paper (international conference proceedings)  

    This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic light as the transmitter and camera as the receiver. The traffic light is composed of a hundred of LEDs on two dimensional plain. In this system, data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually, and they are received as images by the camera. Here, there are problems that neighboring LEDs on the received image are merged due to less number of pixels in case that the receiver is distant from the transmitter, and/or due to blurring by defocus of the camera. Because of that, bit error rate (BER) increases due to recognition error of intensity of LEDs To solve the problem, we propose a method that estimates the intensity of LEDs by solving the inverse problem of communication channel characteristic from the transmitter to the receiver. The proposed method is evaluated by BER characteristics which are obtained by computer simulation and experiments. In the result, the proposed method can estimate with better accuracy than the conventional methods, especially in case that the received image is blurred a lot, and the number of pixels is small. © 2013 SPIE-IS&amp
    T.

    DOI: 10.1117/12.2005738

    Scopus

  222. Interpixel Interference Cancellation Method for Road-to-Vehicle Visible Light Communication Reviewed

    Kasashima Tatsuya, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Yendo Tomohiro, Arai Shintaro

    2013 IEEE 5TH INTERNATIONAL SYMPOSIUM ON WIRELESS VEHICULAR COMMUNICATIONS (WIVEC)     2013

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    Web of Science

  223. Utilization of spatio-temporal image for LED array acquisition in Road to Vehicle Visible Light Communication Reviewed

    Usui S.

    20th ITS World Congress Tokyo 2013     2013

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  224. 査読の虎の巻 Reviewed

    山里 敬也, 佐波 孝彦, 塩田 茂雄, 太田 能

    電子情報通信学会 通信ソサイエティマガジン   Vol. 6 ( 3 ) page: 222 - 230   2013

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    Publishing type:Research paper (scientific journal)   Publisher:一般社団法人 電子情報通信学会  

    DOI: 10.1587/bplus.6.222

    CiNii Article

  225. A Study on the Simulator Development for Visible Light Communication Using LED and Camera Reviewed

    T. Fukumoto, S. Arai, T. Yendo, T. Yamazato, H. Okada and T. Fujii

    Proceedings of IEEE Workshop on Nonlinear Circuit Networks (NCN'12)   ( pp. 124-127 ) page: -   2012.12

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    This paper develops a simple simulation program for visible light communication (VLC) systems using LED (Transmitter) and a camera (Receiver). In the simulation, we generate an image of LED array transmitter which consists of LEDs arranged in a square matrix. In addition, effects of optical spatial channel, which is a unique channel in VLC, are constructed by using image processing techniques. We describe a system model of the VLC simulator and carry out the simulation with various parameters of the image processing.

  226. Intensity estimation of LED array for parallel visible light communication

    T. Ito, S. Arai, T. Yendo T. Yamazato, H. Okada and T. Fujii

    Technical Report of IEICE   ( CS2012-90 ) page: pp.113-118   2012.12

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  227. Visible light communication system using real-time software processing of high-speed camera image

    M. Kasai, T. Yendo T. Yamazato, H. Okada, T. Fujii and S. Arai

    Technical Report of IEICE   ( CS2012-83 ) page: pp.71-75   2012.12

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  228. Intensity estimate of LED array for parallel Visible Light Communication Reviewed

    ITO Takanori, YENDO Tomohiro, ARAI Shintaro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki

    IEICE technical report. Image engineering   Vol. 112 ( 335 ) page: 113 - 118   2012.12

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic light as the transmitter and camera as the receiver. The traffic light is composed of a hundred of LEDs on two dimensional plain. In this system, data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually, and they are received as images by the camera. Here, there are problems that neighboring LEDs on the received image are merged due to less number of pixels in case that the receiver is distant from the transmitter, and/or due to blurring by defocus of the camera. Because of that, bit error rate (BER) increases due to recognition error of intensity of LEDs. To solve the problem, we propose a method that estimates the intensity of LEDs by solving the inverse problem of communication channel characteristic from the transmitter to the receiver. The proposed method is evaluated by BER characteristics which are obtained by computer simulation and experiments. In the result, the proposed method can estimate with better accuracy than the conventional methods, especially in case that the received image is blurred a lot, and the number of pixels is small.

    CiNii Article

  229. Intensity estimate of LED array for parallel Visible Light Communication Reviewed

    ITO Takanori, YENDO Tomohiro, ARAI Shintaro, YAMAZATO Takaya, Okada Hiraku, Fuji Toshiaki

    IEICE technical report. Communication systems   Vol. 112 ( 334 ) page: 113 - 118   2012.12

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic light as the transmitter and camera as the receiver. The traffic light is composed of a hundred of LEDs on two dimensional plain. In this system, data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually, and they are received as images by the camera. Here, there are problems that neighboring LEDs on the received image are merged due to less number of pixels in case that the receiver is distant from the transmitter, and/or due to blurring by defocus of the camera. Because of that, bit error rate (BER) increases due to recognition error of intensity of LEDs. To solve the problem, we propose a method that estimates the intensity of LEDs by solving the inverse problem of communication channel characteristic from the transmitter to the receiver. The proposed method is evaluated by BER characteristics which are obtained by computer simulation and experiments. In the result, the proposed method can estimate with better accuracy than the conventional methods, especially in case that the received image is blurred a lot, and the number of pixels is small.

    CiNii Article

  230. Visible light communication system using real-time software processing of high-speed camera image Reviewed

    KASAI Makoto, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, ARAI Shintaro

    IEICE technical report. Image engineering   Vol. 112 ( 335 ) page: 71 - 75   2012.12

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We focus on a road-to-vehicle Visible Light Communication (VLC) system using LED traffic light as the transmitter and high-speed camera as the receiver. Data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually. At the receiver side, the pattern is captured in the high-speed camera image. It is necessary to find the position of transmitter in the image and to extract the intensity of each LED at high-frame rate in real-time. In this paper, we achieve tracking of the transmitter and intensity extraction in real-time by only software processing on PC.

    CiNii Article

  231. Visible light communication system using real-time software processing of high-speed camera image Reviewed

    KASAI Makoto, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, ARAI Shintaro

    IEICE technical report. Communication systems   Vol. 112 ( 334 ) page: 71 - 75   2012.12

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We focus on a road-to-vehicle Visible Light Communication (VLC) system using LED traffic light as the transmitter and high-speed camera as the receiver. Data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually. At the receiver side, the pattern is captured in the high-speed camera image. It is necessary to find the position of transmitter in the image and to extract the intensity of each LED at high-frame rate in real-time. In this paper, we achieve tracking of the transmitter and intensity extraction in real-time by only software processing on PC.

    CiNii Article

  232. The key to peer-review an IEICE article Reviewed

    T. Yamazato, T. Saba, S. Shiota, C. Ohta

    IEICE Communication Society Magazine   Vol. No.23 [冬号]   page: pp.222-230   2012.12

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    Language:Japanese  

  233. Multiple Information Sources Recognition Method for Ubiquitous Visible Light Communication Using on-Vehicle High-Speed Camera Reviewed

    Y. Shiraki, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

    IEICE Transactions on Communications   Vol. J95-B ( 11 ) page: 1517-1528   2012.12

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  234. A Study on Error-Correcting Method for Noncoherent Chaos Communications Reviewed

    S. Arai, Y. Nishio, T. Yamazato

    Japan-Korea Joint Workshop on Complex Communication Sciences     page: -   2012.11

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  235. Multiple Information Sources Recognition Method for Ubiquitous Visible Light Communication Using on-Vehicle High-Speed Camera Reviewed

    Y. Shiraki, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

    IEICE Transactions on Communications   Vol. J95-B ( no.11 ) page: pp.1517-1528   2012.11

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  236. Multiple Information Sources Recognition Method for Ubiquitous Visible Light Communication Using on-Vehicle High-Speed Camera Reviewed

    SHIRAKI Yasutake, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    The transactions of the Institute of Electronics, Information and Communication Engineers. B   Vol. 95 ( 11 ) page: 1517 - 1528   2012.11

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  237. Improvement of Error-Correcting Method Based on Chaotic Dynamics for Noncoherent Chaos Communications Reviewed

    S. Arai, Y. Nishio, T. Yamazato

    International Symposium on Nonlinear Theory and its Applications (NOLTA'12)     page: pp.801-804   2012.10

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    This paper focuses on characteristics of the chaotic dynamics and improves our previous errorcorrecting method using them for noncoherent chaos communications. Our previous method is performed by using a chaotic sequence generated according to the chaotic dynamics. In this case, it is very difficult to recover data without a successive sequence based on the chaotic dynamics. We focus on this feature and consider that an improved method separates and reconstructs the chaotic dynamics of the sequence according to a specific rule. Namely, the separation and reconstruction of the chaotic dynamics can be applied for our improved method as additional information. As results of simulations, we have confirmed that the advantage gained in BER performance of our improved method is about 2&#8211;2.5 dB compared to a conventional method (without coding).

  238. Introduction of Nagoya University OCW

    T. Yamazato

    ICTSFC Workshop     page: -   2012.9

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  239. Stochastic Resonance BFSK Receiver using Schmitt Trigger

    K. Chiga, H. Tanaka, T. Yamazato, S. Arai

    Enginnering Sciences Society Conference of IEICE   ( A-2-1 ) page: p.24   2012.9

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  240. Performance Evaluation of 2 users BFSK Receiver Stochastic Resonance

    H. Tanaka, T. Yamazato, S. Arai

    Enginnering Sciences Society Conference of IEICE   ( A-2-2 ) page: p.25   2012.9

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  241. Phase Only Correlation Based Distance Estimation Scheme for Integrated R2V-VLC

    A.Ohmura,T.Yamazato,H.Okada,T.Fujii,T.Yendo,S.Arai

        page: -   2012.9

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  242. A Study on Cluster Lifetime in Multi-Hop Wireless Sensor Networks with Cooperative MISO Scheme Reviewed

    Z. Huang, H. Okada, K. Kobayashi, M. Katayama

    Journal of Communications and Networks   Vol. 14 ( no.4 ) page: pp.443-450   2012.8

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    As for cluster-based wireless sensor networks (WSNs), cluster lifetime is one of the most important subjects in recent researches. Besides reducing the energy consumptions of the clusters, it is necessary to make the clusters achieve equal lifetimes so that the whole network can survive longer. In this paper, we focus on the cluster lifetimes in multi-hop WSNs with cooperative multi-input single-output scheme. With a simplified model of multi-hop WSNs, we change the transmission schemes, the sizes and transmission distances ofclusters to investigate their effects on the cluster lifetimes. Furthermore, linear and uniform data aggregations are considered in our model. As a result, we analyze the cluster lifetimes in different situations and discuss the requirements on the sizes and transmission distances of clusters for equal lifetimes.

    DOI: 10.1109/JCN.2012.6292251

  243. A-2-1 Stochastic Resonance BFSK Receiver using Schmitt Trigger Reviewed

    CHIGA Keita, TANAKA Hiroya, YAMAZATO Takaya, ARAI Shintaro

    Proceedings of the Society Conference of IEICE   Vol. 2012   2012.8

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  244. A-2-2 Performance Evaluation of 2 users BFSK Receiver using Stochastic Resonance Reviewed

    TANAKA Hiroya, YAMAZATO Takaya, ARAI Shintaro

    Proceedings of the Society Conference of IEICE   Vol. 2012   2012.8

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  245. Demand of Teaching Material Development and OCW

    T. Yamazato

    60th JSEE Anual Conference Proceedings   ( 8-331 ) page: -   2012.8

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  246. Interference Comparison of BFDM and Wavelet Based OFDM in Frequency Dispersive Channels Reviewed

    GOTO Daisuke, YAMAZATO Takaya, MONGOL Bayarpurev

    The transactions of the Institute of Electronics, Information and Communication Engineers. B   Vol. 95 ( 8 ) page: 971 - 975   2012.8

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  247. Evbaluation of Error-Correcting Method Using Separation of Chaotic Dynamics for Noncoherent Chaos Communications

    S. Arai, Y. Nishio and T. Yamazato

        page: pp. 261-266   2012.7

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  248. Improvement Method of Data Rate for Overlay Hierarchical Coding for Road-to-Vehicle Visible Light Communication Using LED Array and High-Speed Camera

    S. Nishimoto, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

    Technical Report of IEICE   Vol. no.148 ( ITS2012-9 ) page: pp.19-24   2012.7

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    This paper aims to improve the data rate for the visible light communication system using LED array and high-speed camera. Previously, we have proposed the decoding algorithm using inverted signals for driving situation. However, using this method the data rate become a half, because we transmit original signals and inverted signals alternately for LED array tracking. In this paper, we propose the data rate improving method for overlay coding which is coding method that overlay two data. We confirm that we can improve data rate as compared with the previous method.

  249. Improvement Method of Data Rate for Overlay Hierarchical Coding for Road-to-Vehicle Visible Light Communication Using LED Array and High-Speed Camera Reviewed

    NISHIMOTO Sayaka, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

      Vol. 112 ( 148 ) page: 19 - 24   2012.7

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    This paper aims to improve the data rate for the visible light communication system using LED array and high-speed camera. Previously, we have proposed the decoding algorithm using inverted signals for driving situation. However, using this method the data rate become a half, because we transmit original signals and inverted signals alternately for LED array tracking. In this paper, we propose the data rate improving method for overlay coding which is coding method that overlay two data. We confirm that we can improve data rate as compared with the previous method.

    CiNii Article

  250. Driver Assistant System using Visible Light Communications : Road-to-Vehicle Visible Light Communications usign LED Array and On-Vehicle High-Speed Camera Reviewed

    YAMAZATO Takaya

    IEICE technical report. WBS, Wideband System   Vol. 112 ( 147 ) page: 25 - 30   2012.7

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    We are conducting a study on visible light communications (VLC) using an LED traffic light and a high-speed camera equipped in a vehicle. Since we use the camera, we can capture and record surround images of the vehicle while receiving the data transmitted from the LED traffic light. This paper introduces the VLC system we are working on. Especially, this paper describes the advantages of road-to-vehicle VLC when the reception device is composed of high-speed camera.

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  251. [Poster Presentation] Road-to-Vehicle Communication and Distance Estimation System using Visible Light Communication

    A.Ohmura,T.Yamazato,H.Okada,T.Fujii,T.Yendo,S.Arai

    Technical Report of IEICE   ( USN2012-9 ) page: pp.63-68   2012.5

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    In road-to-vehicle visible light communication data is transmitted toward moving vehicles from theLED array installed on roads. Robust data reception and fast communication are possible by using a high-speedcamera as it can reduce the vibration of vehicles. In this road-to-vehicle visible light communication, we propose anintegrated system of communication and distance estimation by sending a known data pattern.

  252. Road-to-Vehicle Communication and Distance Estimation System using Visible Light Communication Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    IEICE technical report   Vol. 112 ( 31 ) page: 63 - 68   2012.5

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    In road-to-vehicle visible light communication data is transmitted toward moving vehicles from the LED array installed on roads. Robust data reception and fast communication are possible by using a high-speed camera as it can reduce the vibration of vehicles. In this road-to-vehicle visible light communication, we propose an integrated system of communication and distance estimation by sending a known data pattern from the LED array.

    CiNii Article

  253. A Study on Cluster Partitioning with Cooperative MISO Scheme in Wireless Sensor Networks Reviewed

    Z. Huang, H. Okada, M. Katayama, T. Yamazato

    International Journal of Distributed Sensor Networks     page: -   2012.4

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    This paper addresses the cluster partitioning problem in wireless sensor networks deployed in a continuous area. We present the model of the network and describe its operational details firstly. Both single-hop and multi-hop transmissions with cooperative Multi-Input Single-Output (MISO) scheme are considered for the inter-cluster communications. Besides, uniform and linear data fusions are discussed. Then the calculations of energy consumptions are derived. Different from other researches, the energy consumptions of intra-cluster communication in each cluster are included and modeled as functions of the cluster size. Finally, we simulate all possible cluster partitions by changing the numbers of clusters and cooperative transmitting nodes, and find the maximal network lifetimes. As a result, the relationships between cluster partitions and network lifetimes are clarified in different situations.

  254. A Distance Estimation Scheme between the LED Array and On-Vihicle High-Speed Camera Using Visible Light

    A.Ohmura,T.Yamazato,H.Okada,T.Fujii,T.Yendo,S.Arai

    IEICE General Conference   Vol. B-10B   page: CD-ROM   2012.3

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  255. Preliminary Study on Bi-Polar Pulse Receiver using Stochastic Resonance

    H. Tanaka, T. Yamazato, S. Arai

    IEICE General Conference   Vol. A-2   page: CD-ROM   2012.3

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  256. A-2-34 Preliminary Study on Bi-Polar Pulse Receiver using Stochastic Resonance Reviewed

    TANAKA Hiroya, YAMAZATO Takaya, ARAI Shintaro

    Proceedings of the IEICE General Conference   Vol. 2012   2012.3

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  257. A-2-35 State Analysis of Stochastic Resonance in Quadruple-Well Potential Reviewed

    Ozaki Shota, Arai Shintaro, Yamazato Takaya, Nishio Yoshifumi

    Proceedings of the IEICE General Conference   Vol. 2012   2012.3

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  258. Relay Selection Scheme with Harvested Solar Energy Prediction for Solar-Powered Wireless Sensor Networks Reviewed

    OTA KENTARO, KOBAYASHI KENTARO, YAMAZATO TAKAYA, KATAYAMA MASAAKI

    IEICE technical report   Vol. 111 ( 476 ) page: 85 - 92   2012.3

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    Our goal is to make efficient use of the energy and therefore achieve network operation with a high packet delivery ratio, regardless of day, night and weather variations, in solar powered wireless sensor networks. One method to optimize the consumption energy in the entire network is to employ a cooperative transmission scheme in which a node uses another node as a relay, when sending its data. If we do not consider the changes in the harvested energy in the network, the packet delivery ratio declines during nights and cloudy days. In this paper, however, we propose a new relay selection scheme with harvested solar energy prediction to maintain the required high packet delivery ratio by reducing the effect of the weather variations.

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  259. Preliminary Study on BPSK Receiver using Stochastic Resonance Reviewed

    H.Tanaka, T.Yamazato, S.Arai

    2012 RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing     page: CD-ROM   2012.3

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    Stochastic Resonance (SR), known as a noise-enhanced phenomenon, can improve the performance of commutation systems. In this paper, we present a preliminary study on SR and its application to BPSK receiver. We discuss a basic question arises from a receiver using SR that shall we perform SR process in a radio-frequency (RF) band or in a baseband (BB)? As results, we found that SR process in RF band shows better Bit Error Rate (BER) performance. This comes from the fact that a down conversion process that reduces the signal amplitude causes weak noise suppression by SR. While a double frequency term obtained also by the down conversion process do not affect much to the noise reduction performance.

  260. Cancellation Method for Intersymbol Interference on Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera Reviewed

    KASASHIMA Tatsuya, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

      Vol. 111 ( 441 ) page: 129 - 134   2012.2

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    In this paper, we discuss on visible light communications using an LED array as the transmitter and a highspeed camera as the receiver. LED array , composed of many LEDs, transmits information by flashing LEDs, unfortunately an LED light diffuses around and affects neighboring LEDs. This problem causes degradation in error rate performance. We treat this ploblem as intersymbol interference (ISI) and try to cancel. In this paper, we first propose an area average quantization for the reduction of ISI. Next, we propose a new ISI cancellation method for overlay decoding and evaluate this method.

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  261. Cancellation Method for Intersymbol Interference on Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera Reviewed

    KASASHIMA Tatsuya, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

      Vol. 111 ( 441 ) page: 129 - 134   2012.2

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  262. Cancellation Method for Intersymbol Interference on Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera Reviewed

    KASASHIMA Tatsuya, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    IEICE technical report. Image engineering   Vol. 111 ( 442 ) page: 129 - 134   2012.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we discuss on visible light communications using an LED array as the transmitter and a highspeed camera as the receiver. LED array , composed of many LEDs, transmits information by flashing LEDs, unfortunately an LED light diffuses around and affects neighboring LEDs. This problem causes degradation in error rate performance. We treat this ploblem as intersymbol interference (ISI) and try to cancel. In this paper, we first propose an area average quantization for the reduction of ISI. Next, we propose a new ISI cancellation method for overlay decoding and evaluate this method.

    CiNii Article

  263. LED Array Tracking Method for Road-to-Vehicle Visible Light Communications in the Driving Situation Reviewed

    T. Nagura, T. Yamazato, S. Arai, H. Okada, T. Yendo, T. Fujii

    IEICE Transactions on Communications   Vol. J95-B ( 2 ) page: 326-336   2012.2

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  264. Gaussian Pulse Shape Optimization of BFDM in Highly Mobile Environments Reviewed

    D. Goto, T. Yayazato, B. Mongol

    IEICE Transactions on Communications   Vol. J95-B ( 2 ) page: 317-325   2012.2

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    In this paper, we focus on reducing intersymbol interference (ISI) and intercarrier interference (ICI) in a highly mobile environment by optimizing the Gaussian pulse shape of Biorthogonal Frequency Division Multiplexing (BFDM). In time-frequency dispersive channels, reducing the signal interference depends on the shaping of signal pulse. BFDM was invented to reduce the interference through a flexible design of signal pulse shaping. However, the shape of Gaussian pulses used in BFDM is not always optimized in every situation and as a result the interference is not always minimized. This research is to optimize the shape of Gaussian pulse. In particular, we optimize the Gaussian pulse in BFDM by maximizing the ratio of the ambiguity function of the transmitter (Gaussian) and its receiver pulses. Numerical results obtained show that the proposed method is effective for the optimization of BFDM. Furthermore, we show that the BFDM outperforms the conventional OFDM in time-frequency dispersive channels.

  265. Cooperative Transmission Scheme with the Reactivation Condition of Inactive Nodes in Solar-Powered Wireless Sensor Networks Reviewed

    K. Ota, K. Kobayashi, T. Yamazato, M. Katayama

    IEICE Transactions on Communications   Vol. J95-B ( 2 ) page: 246-256   2012.2

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    Our goal is the improvement of the data arrival rate in solar-powered wireless sensor networks. We consider the application of a cooperative transmission scheme that uses a relay node when a node sends data to reduce the consumption of energy of the entire network. In this paper, we propose the selection method of a relay node based on node battery and consumption energy. The overall data arrival rate is improved through the method. However, if we do not consider the variations in energy harvesting, the data arrival rate declines during nighttime. Then, we smooth out the day-and-night data arrival rate variations by introducing the new inactive node reactivation condition to the cooperative transmission scheme and achieve the required high data arrival rate.

  266. Cooperative Transmission Scheme with the Reactivation Condition of Inactive Nodes in Solar-Powered Wireless Sensor Networks Reviewed

    OTA Kentaro, KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    The transactions of the Institute of Electronics, Information and Communication Engineers. B   Vol. 95 ( 2 ) page: 246 - 256   2012.2

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  267. LED Array Tracking Method for Road-to-Vehicle Visible Light Communications in the Driving Situation Reviewed

    T. Nagura, T. Yamazato, S. Arai, H. Okada, T. Yendo, T. Fujii

    IEICE Transactions on Communications   Vol. J95-B ( 2 ) page: 326-336   2012.2

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  268. Gaussian Pulse Shape Optimization of BFDM in Highly Mobile Environments Reviewed

    GOTO Daisuke, YAMAZATO Takaya, MONGOL Bayarpurev

    The transactions of the Institute of Electronics, Information and Communication Engineers. B   Vol. 95 ( 2 ) page: 317 - 325   2012.2

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  269. LED Array Tracking Method for Road-to-Vehicle Visible Light Communications in the Driving Situation Reviewed

    NAGURA Toru, YAMAZATO Takaya, ARAI Shintaro, OKADA Hiraku, YENDO Tomohiro, FUJII Toshiaki

    The transactions of the Institute of Electronics, Information and Communication Engineers. B   Vol. 95 ( 2 ) page: 326 - 336   2012.2

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  270. A Simple Cooperative Relaying with Alamouti Coded Transmission Reviewed

    Tomoya Yamaoka, Yoshitaka Hara, Noriyuki Fukui, Hiroshi Kubo, Takaya Yamazato

    IEICE TRANSACTIONS ON COMMUNICATIONS   Vol. E95B ( 2 ) page: 643 - 646   2012.2

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    Publishing type:Research paper (scientific journal)   Publisher:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Cooperative diversity using space-time codes offers effective space diversity with low complexity, but the scheme needs the space-time coding process in the relay nodes. We propose a simple cooperative relay scheme that uses space-time coding. In the scheme, the source node transmits the Alamouti coded signal sequences and the sink node receives the signal sequence via the two coordinated relay nodes. At the relay nodes, the operation procedure is just permutation and forwarding of the signal sequence. In the proposed scheme, none of the relay nodes need quadrature detection and space-time coding and the simple relay process offers effective space diversity. Moreover, simulations show the effectiveness Of the proposed relay process by some simulations.

    DOI: 10.1587/transcom.E95.B.643

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  271. [Technology Exhibition] Real-Time Data Transmission of Road-to-Vehicle Visible Light Communication System Using LED array and High-Speed Camera

    T.Kasashima, Y.Shiraki, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

    Technical Report of IEICE   Vol. USN2011-89   page: 173-175   2012.1

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    In this paper, we discuss road-to-vehicle visible light communications using an LED array as the transmitter and a high-speed camera as the receiver. The visible light communication (VLC) is a wireless communication that a transmitter consists of LED array and it transmit data by Turing LEDs on and off at high speed. We consider applying this VLC technique to the road (infrastructure) -to-vehicle communication for a purpose to support safety driving. So far, we have confirmed effectiveness of the VLC system through static and driving experiments. However, all those experimental results were obtained by off-line processing.

  272. Decline in Probability of False Recognition of Non-Information Sources in Visible Light Communication for Intelligent Transport System

    Y. Shiraki, T. Yamazato, S. Arai, T. Yendo, H. Okada, T. Fujii

    Technical Report of IEICE   Vol. USN2011-59   page: 13-18   2012.1

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  273. Technology Exhibition : Real-Time Data Transmission of Road-to-Vehicle Visible Light Communication System Using LED array and High-Speed Camera Reviewed

    KASASHIMA Tatsuya, SHIRAKI Yasutake, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    IEICE technical report   Vol. 111 ( 386 ) page: 173 - 175   2012.1

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we discuss road-to-vehicle visible light communications using an LED array as the transmitter and a high-speed camera as the receiver. The visible light communication (VLC) is a wireless communication that a transmitter consists of LED array and it transmit data by Turing LEDs on and off at high speed. We consider applying this VLC technique to the road (infrastructure) -to-vehicle communication for a purpose to support safety driving. So far, we have confirmed effectiveness of the VLC system through static and driving experiments. However, all those experimental results were obtained by off-line processing. In this paper, we introduce a real-time processing of the VLC receiver that captures not only the captured images by also the data transmitted from the LED array. The detail of the VLC receiver will be shown at the technology exhibition.

    CiNii Article

  274. Real-Time Data Transmission of Road-to-Vehicle Visible Light Communication System Using LED Array and High-Speed Camera Reviewed

    KASASHIMA Tatsuya, SHIRAKI Yasutake, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

      Vol. 111 ( 386 ) page: 173 - 175   2012.1

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  275. Real-Time Data Transmission of Road-to-Vehicle Visible Light Communication System Using LED Array and High-Speed Camera Reviewed

    KASASHIMA Tatsuya, SHIRAKI Yasutake, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    IEICE technical report   Vol. 111 ( 384 ) page: 87 - 89   2012.1

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we discuss road-to-vehicle visible light communications using an LED array as the transmitter and a high-speed camera as the receiver. The visible light communication (VLC) is a wireless communication that a transmitter consists of LED array and it transmit data by Turing LEDs on and off at high speed. We consider applying this VLC technique to the road (infrastructure) -to-vehicle communication for a purpose to support safety driving. So far, we have confirmed effectiveness of the VLC system through static and driving experiments. However, all those experimental results were obtained by off-line processing. In this paper, we introduce a real-time processing of the VLC receiver that captures not only the captured images by also the data transmitted from the LED array. The detail of the VLC receiver will be shown at the technology exhibition.

    CiNii Article

  276. Decline in Probability of False Recognition of Non-Information Sources in Visible Light Communication for Intelligent Trasport System Reviewed

    SHIRAKI Yasutake, YAMAZATO Takaya, ARAI Shintaro, YENDO Tomohiro, OKADA Hiraku, FUJII Toshiaki

    IEICE technical report   Vol. 111 ( 386 ) page: 13 - 18   2012.1

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Visible light communication systems which enable data transmission by blinking LEDs at fast rate attract attention for their applications to Intelligent Transport Systems (ITS). In this paper, we assume that there are multiple information sources and we recognize them with on-vehicle high-speed camera in such systems. To lower probability of false recognition which represents how often non-information sources are recognized as information sources, we propose an improved multiple sources recognition method. We evaluate the proposed method by performing experiments.

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  277. High-Speed LED Traffic Light Tracking Method Using Image/High-Speed Communication Hybrid Sensor Reviewed

    K. Maeno, M. Tehrani, T. Fujii, H. Okada, T. Yamazato, M. Tanimoto, T. Yendo

    International Workshop on Advanced Image Technology (IWAIT2012)     page: CD-ROM   2012.1

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    Visible Light Communication (VLC) is a wireless communication method using LEDs. In this paper, we use a hybrid sensor designed for VLC which has advantages of photodiode and high-speed camera, that is, high transmission rate and easy detecting of the transmitter. The light receiving section of the sensor consists of communication pixels and video pixels. This sensor can communicate in static environment in previous research. However in dynamic environment, high- speed tracking of the transmitter is essential. We realize the high-speed tracking of the transmitter using the information of the communication pixels. Experimental results show the possibility of communication in dynamic environment.

  278. High-speed Transmission of Overlay Coding for Road-to-Vehicle Visible Light Communication Using LED Array and High-Speed Camera Reviewed

    Sayaka Nishimoto, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Tomohiro Yendo, Shintaro Arai

    2012 IEEE GLOBECOM WORKSHOPS (GC WKSHPS)   ( pp.1234-1238 ) page: 1234 - 1238   2012

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This paper aims to the improve the data rate for the visible light communication system using LED array and high-speed camera. Previously, we have proposed the decoding algorithm using inverted signals for driving situation. However, using this method the data rate become a half, because we transmit original signals and inverted signals alternately for LED array tracking. In this paper, we propose the data rate improving method for overlay coding which is coding method that overlay two data which are called as the long range data and the short range data. In the proposed method, for the long range data, we transmit original signals and inverted signals alternately. On the other hand, for the short range data, we transmit only original signals while we transmit inverted signals of long range data. We confirm that we can improve data rate as compared with the previous method.

    DOI: 10.1109/GLOCOMW.2012.6477757

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    Scopus

  279. 8-331 Demand of Teaching Material Development and OCW Reviewed

    YAMAZATO Takaya

    Proceedings of Annual Conference of Japanese Society for Engineering Education   Vol. 2012 ( 0 ) page: 718-719   2012

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    DOI: 10.20549/jseeja.2012.0_718

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  280. A Study on Cluster Partitioning with Cooperative MISO Scheme in Wireless Sensor Networks Reviewed

    Zheng Huang, Hiraku Okada, Masaaki Katayama, Takaya Yamazato

    INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS   Vol. 8   2012

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    Publishing type:Research paper (scientific journal)   Publisher:HINDAWI PUBLISHING CORPORATION  

    This paper addresses the cluster partitioning problem in wireless sensor networks deployed in a continuous area. We present the model of the network and describe its operational details firstly. Both single-hop and multihop transmissions with cooperative Multi-Input Single-Output (MISO) scheme are considered for the intercluster communications. Besides, uniform and linear data fusions are discussed. Then, the calculations of energy consumptions are derived. Different from other researches, the energy consumptions of intracluster communication in each cluster are included and modeled as functions of the cluster size. Finally, we simulate all possible cluster partitions by changing the numbers of clusters and cooperative transmitting nodes and find the maximal network lifetimes. As a result, the relationships between cluster partitions and network lifetimes are clarified in different situations.

    DOI: 10.1155/2012/490823

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  281. B-10-103 A Distance Estimation Scheme between the LED Array and On-Vihicle High-Speed Camera Using Visible Light Communication Reviewed

    OHMURA Akihiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, YENDO Tomohiro, ARAI Shintaro

    Proceedings of the IEICE General Conference   Vol. 2012 ( 2 )   2012

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  282. Gaussian Pulse Shape Optimization of BFDM in Time-Frequency Dispersive Channels Reviewed

    Goto Daisuke, Yamazato Takaya, Mongol Bayarpurev

    2012 IEEE 75TH VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING)     2012

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    Web of Science

  283. High-speed Transmission of Overlay Coding for Road-to-Vehicle Visible Light Communication Using LED Array and High-Speed Camera Reviewed

    Nishimoto Sayaka, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Yendo Tomohiro, Arai Shintaro

    2012 IEEE GLOBECOM WORKSHOPS (GC WKSHPS)     page: 1234 - 1238   2012

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    Web of Science

  284. Gaussian Pulse Shape Optimization of BFDM in Time-Frequency Dispersive Channels Reviewed

    Daisuke Goto, Takaya Yamazato, Bayarpurev Mongol

    2012 IEEE 75TH VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING)     page: 1 - 5   2012

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    The objective of this research is to reduce inter-symbol interference (ISI) and intercarrier interference (ICI) in a highly mobile environment by optimizing the performance of Biorthogonal Frequency Division Multiplexing (BFDM). In time-frequency dispersive channels, reducing the signal interference depends on the shaping of the signal pulse. BFDM was invented to reduce the interference through a flexible design of the signal pulse shaping. However, the shape of the Gaussian pulses used in BFDM is not always optimized in every situation and as a result the interference is not always minimized. This research seeks to optimize the shape of the Gaussian pulse. In particular, we optimize the Gaussian pulse in BFDM by maximizing the ratio of the ambiguity function of the transmitter (Gaussian) and its receiver pulses. Numerical results obtained show that the proposed method is effective for the optimization of BFDM. Furthermore, we show that the optimized BFDM outperforms the conventional OFDM in time-frequency dispersive channels.

    DOI: 10.1109/VETECS.2012.6240287

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  285. Visible light communication in dynamic environment using image/high-speed communication hybrid sensor Reviewed

    Keita Maeno, Mehrdad Panahpour Tehrani, Toshiaki Fujii, Hiraku Okada, Takaya Yamazato, Masayuki Tanimoto, Yendo Tomohiro

    BROADBAND ACCESS COMMUNICATION TECHNOLOGIES VI   Vol. 8282   2012

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    Publishing type:Research paper (international conference proceedings)   Publisher:SPIE-INT SOC OPTICAL ENGINEERING  

    Visible Light Communication (VLC) is a wireless communication method using LEDs. LEDs can respond in high-speed and VLC uses this characteristics. In VLC researches, there are two types of receivers mainly, one is photodiode receiver and the other is high-speed camera. A photodiode receiver can communicate in high-speed and has high transmission rate because of its high-speed response. A high-speed camera can detect and track the transmitter easily because it is not necessary to move the camera. In this paper, we use a hybrid sensor designed for VLC which has advantages of both photodiode and high-speed camera, that is, high transmission rate and easy detecting of the transmitter. The light receiving section of the hybrid sensor consists of communication pixels and video pixels, which realizes the advantages. This hybrid sensor can communicate in static environment in previous research. However in dynamic environment, highspeed tracking of the transmitter is essential for communication. So, we realize the high-speed tracking of the transmitter by using the information of the communication pixels. Experimental results show the possibility of communication in dynamic environment.

    DOI: 10.1117/12.907697

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  286. Relay Selection Scheme Using Prediction of Harvested Energy for Solar-Powered Wireless Sensor Networks Reviewed

    K. Ota, K. Kobayashi, T. Yamazato, M. Katayama

    International Symposium on EcoTopia Science 2011     page: 106   2011.12

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    Solar-powered wireless sensor networks are attracting attention for outdoor long time operation such as environmental monitoring. Even if sensor nodes are charged by solar energy, nodes far from the BS (Base-Station) are stopped due to the lack of energy during nighttime. To prevent this problem, we consider the use of cooperative transmission. In cooperative transmission, energy consumption is balanced among the nodes because of the use of another node as a relay for data transmission of distant nodes. The conventional scheme to select a relay node is based on available battery energy and the expectation of energy consumption of each node. In this paper, we propose a relay selection scheme which is based on the prediction of harvested energy in addition to the available battery energy and the expected value of energy consumption. We evaluate the proposed scheme through packet delivery ratio and show its effectiveness.

  287. Interference Comparison of BFDM with Optimum Gaussian Pulse and Wavelet Based OFDM in Highly Mobile Environments

    D. Goto, T. Yayazato, B. Mongol

    Technical Report of IEICE   Vol. RCS2011-11   page: 91-95   2011.11

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    In this paper, we conduct a comparison between the Biorthogonal Frequency Division Multiplexing (BFDM) and the Wavelet Based Orthogonal Frequency Division Multiplexing (OFDM) in terms of intersymbol interference (ISI) and intercarrier interference (ICI) reduction in highly mobile environments with assumed time-frequency dispersive channels. ISI and ICI depend largely on the pulse shaping of the signal. BFDM can reduce the signal interference by applying a Gaussian pulse known as a properly localized time-frequency pulse with adaptable characteristics. On the other hand, Wavelet Based OFDM is known to lower interference due to its wavelet basis. In this paper, we propose an optimization method for the Gaussian pulse in BFDM to minimize ISI/ICI by maximizing the ratio of the ambiguity function. In addition, we compare its performance with BFDM and Wavelet Based OFDM.

  288. Interference Comparison of BFDM with Optimum Gaussian Pulse and Wavelet Based OFDM in Highly Mobile Environments Reviewed

    GOTO Daisuke, YAMAZATO Takaya, MONGOL Bayarpurev

    Technical report of IEICE. RCS   Vol. 111 ( 289 ) page: 91 - 95   2011.11

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we conduct a comparison between the Biorthogonal Frequency Division Multiplexing (BFDM) and the Wavelet Based Orthogonal Frequency Division Multiplexing (OFDM) in terms of intersymbol interference (ISI) and intercarrier interference (ICI) reduction in highly mobile environments with assumed time-frequency dispersive channels. ISI and ICI depend largely on the pulse shaping of the signal. BFDM can reduce the signal interference by applying a Gaussian pulse known as a properly localized time-frequency pulse with adaptable characteristics. On the other hand, Wavelet Based OFDM is known to lower interference due to its wavelet basis. In this paper, we propose an optimization method for the Gaussian pulse in BFDM to minimize ISI/ICI by maximizing the ratio of the ambiguity function. In addition, we compare its performance with BFDM and Wavelet Based OFDM.

    CiNii Article

  289. Overlay Coding for Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera Reviewed

    S. Nishimoto, T. Nagura, T. Yamazato, T. Yendo, T. Fujii, H. Okada, S. Arai

    International IEEE Conference on Intelligent Transportation Systems     page: 1704-1709   2011.10

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    This paper aims to improve the visible light communication system using LED array and high-speed camera by proposing what we call "overlay coding." "Overlay coding" is a new coding method to realize a hierarchical coding, through which a high-priority data can be received even if the receiver is far from a transmitter. Conventionally, the hierarchical coding has been realized through the wavelet transform that has a limitation of number and disposition of LEDs, and as a result it does not always match with the design of the transmitters (e.g. traffic lights, etc.) used in real life. To solve the limitation problem, we propose a more flexible way of designing the application of LEDs depending on the transmitters. In particular, overlay coding is realized through the procedures of coding and decoding. In coding, we replace one LED with a flexible number of LEDs, and the number depends on whether the data is high-priority or low-priority, then high-priority data and low-priority data are overlaid. In decoding, we first obtain the high-priority data, and then the low-priority data using retrieved high-priority data. The experimental result shows that the distance for receiving error-free data is extended from 30m to 70m in the overlay coding.

  290. A Study on Cluster Lifetime of Single-hop Wireless Sensor Networks with Cooperative MISO Scheme Reviewed

    Z. Huang, K. Kobayashi, M. Katayama, T. Yamazato

    IEICE Transactions on Communications   Vol. E94-B ( 10 ) page: 2881-2885   2011.10

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    This letter investigates the cluster lifetime of single-hop wireless sensor networks with cooperative Multi-Input Single-Output (MISO) scheme. The energy consumptions of both intra-cluster and out-cluster communications are considered. Moreover, uniform and linear data aggregations are discussed. It is found the optimal transmission scheme varies with the distance from the cluster to the base station. More interestingly and novelly, the effect of cluster size on the cluster lifetime has been clarified.

  291. A Study on Cluster Lifetime of Single-Hop Wireless Sensor Networks with Cooperative MISO Scheme Reviewed

    Zheng Huang, Kentaro Kobayashi, Masaaki Katayama, Takaya Yamazato

    IEICE TRANSACTIONS ON COMMUNICATIONS   Vol. E94B ( 10 ) page: 2881 - 2885   2011.10

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    Publishing type:Research paper (scientific journal)   Publisher:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    This letter investigates the cluster lifetime of single-hop wireless sensor networks with cooperative Multi-Input Single-Output (MISO) scheme. The energy consumptions of both intra-cluster and out-cluster communications are considered. Moreover, uniform and linear data aggregations are discussed. It is found the optimal transmission scheme varies with the distance from the cluster to the base station. More interestingly and novelly, the effect of cluster size on the cluster lifetime has been clarified.

    DOI: 10.1587/transcom.E94.B.2881

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  292. Estimation of Channel Information for Error Correcting Code in Visible Light Communication Using LED Array and High-Speed Camera

    S. Misawa, H. Okada, T. Yamazato, T. Yendo, T. Fujii

    Enginnering Sciences Society Conference of IEICE   Vol. A-17-6   page: 210   2011.9

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  293. Cooperative Transmission Scheme with Inactive Node Reactivation Condition for Solar-Powered Wireless Sensor Networks Reviewed

    K. Ota, K. Kobayashi, T. Yamazato, M. Katayama

    IEEE International Workshop on Wireless Distributed Networks (WDN2011)     page: 2394-2398   2011.9

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    Our goal is the improvement of the node activity rate in solar-powered wireless sensor networks. We consider the application of a cooperative transmission scheme that uses a relay node when a node sends data to reduce the consumption of energy of the entire network. However, if we do not consider the variations in energy harvesting, the node activity rate declines during nighttime. In this paper, we smooth out the day-and-night node activity rate variations by introducing the new inactive node reactivation condition and achieve the required high node activity rate.

  294. Instructor's message that can be read from Nagoya Univeristy OCW teaching materials

    T. Yamazato

    Journal of Japanese Society for Engineering Education (JSEE)     page: 9-217   2011.9

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    Of the courses, that have been presented in Nagoya University OCW site, are taken up and discussed in terms of how the educative effect can be improved by stimulating student's intellectual curiosity.

  295. I-074 Road-to-vehicle Visible Light Communication Using High-speed Camera in Driving Situation Reviewed

    Premachandra Halpage Chinthaka Nuwandika, Yendo Tomohiro, Tehrani Mehrdad Panahpour, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Tanimoto Masayuki

    情報科学技術フォーラム講演論文集   Vol. 10 ( 3 ) page: 459 - 464   2011.9

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    Intelligent Transport System(ITS) has been proposed to give solutions for traffic problems such as traffic accidents and traffic jams. On the other hand, high frame rate image techniques are getting popular in last several years. In this paper, we propose a Visible Light Communication(VLC) system using high frame rate techniques for Intelligent Transport System. Here, the communication between infrastructure and the vehicle is approached using an LED array as a transmitter and on-vehicle high speed camera as a receiver. The LEDs in the transmitter emit light in 500Hz and the emission patterns are used to achieve communication, capturing them in high frame rate(1000fps) utilizing a high-speed camera. The images captured by high-speed camera are processed to find the transmitter, track the found transmitter, and capture the LED lighting pattern of transmitter in consecutive frames. In our previous work, we proposed algorithms to finding and tracking. In this paper, we introduce method to capture the lighting pattern of the transmitter. Then, out door communication experiments were conducted to confirm the effectiveness of the proposed V LC system.

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  296. A-17-6 Estimation of Channel Information for Error Correcting Code in Visible Light Communication Using LED Array and High-Speed Camera Reviewed

    MISAWA Shinnosuke, OKADA Hiraku, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki

    Proceedings of the Society Conference of IEICE   Vol. 2011   2011.8

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  297. Unique teaching practices presented at Nagoya University OCW Reviewed

    T. Yamazato

    Journal of Japanese Society for Engineering Education (JSEE)   Vol. 59 ( 4 ) page: 4_105-4_107   2011.8

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  298. Unique Teaching Practices Presented at Nagoya University OCW Reviewed

    YAMAZATO Takaya

    Journal of JSEE   Vol. 59 ( 4 ) page: 105 - 107   2011.7

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    DOI: 10.4307/jsee.59.4_105

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  299. Multiple LED Arrays Recognition Using Block Matching for Road-to-Vehicle Visible Light Communication

    Y. Shiraki, T. Yamazato, S. Arai, T. Yendo, H. Okada, T. Fujii

    Technical Report of IEICE   Vol. USN2011-18   page: 73-78   2011.7

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    Visible light communication systems which enable data transmission by blinking LEDs at fast rate attract attention for their applications to Intelligent Transport Systems (ITS). In this paper, we assume that there are multiple information sources and we recognize them with on-vehicle high-speed camera in such systems. To distinguish multiple sources, we propose multiple sources recognition method based block matching. We evaluate the proposed method by performing experiments.

  300. Multiple LED Arrays Recognition Using Block Matching for Road-to-Vehicle Visible Light Communication Reviewed

    SHIRAKI Yasutake, YAMAZATO Takaya, ARAI Shintaro, YENDO Tomohiro, OKADA Hiraku, FUJII Toshiaki

    IEICE technical report   Vol. 111 ( 134 ) page: 73 - 78   2011.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Visible light communication systems which enable data transmission by blinking LEDs at fast rate attract attention for their applications to Intelligent Transport Systems (ITS). In this paper, we assume that there are multiple information sources and we recognize them with on-vehicle high-speed camera in such systems. To distinguish multiple sources, we propose multiple sources recognition method based block matching. We evaluate the proposed method by performing experiments.

    CiNii Article

  301. Visible Light Communication and Its Application to ITS

    T. Yamazato

    International Symposium on Emerging Short Range Communications     page: -   2011.6

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  302. Gaussian Pulse Shape Optimization of BFDM in Highly Mobile Environments

    D. Goto, T. Yamazato, B. Mongol

    Technical Report of IEICE   Vol. RCS2011-06   page: 221-226   2011.6

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    In this paper, we focus on reducing intersymbol interference (ISI) and intercarrier interference (ICI) in a highly mobile environment by optimizing the Gaussian pulse shape of Biorthogonal Frequency Division Multiplexing (BFDM). In time-frequency dispersive channels, reducing the signal interference depends on the shaping of signal pulse. BFDM was invented to reduce the interference through a flexible design of signal pulse shaping. However, the shape of Gaussian pulses used in BFDM is not always optimized in every situation and as a result the interference is not always minimized. This research is to optimize the shape of Gaussian pulse. In particular, we optimize the Gaussian pulse in BFDM by maximizing the ratio of the ambiguity function of the transmitter (Gaussian) and its receiver pulses. Numerical results obtained show that the proposed method is effective for the optimization of BFDM. Furthermore, we show that the BFDM outperforms the conventional OFDM in time-frequency dispersive channels.

  303. [Requested Talk] What Visible Light Communication (VLC) can do, what VLC cannot do. What I found from the research on VLC using LED array and High-Speed Invited

    T. Yamazato

    Technical Report of IEICE   Vol. RCS2011-49   page: 85-90   2011.6

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    We are conducting a study on visible light communications (VLC) using an LED traffic light and a high-speed camera equipped in a vehicle. Since we use the camera, we can capture and record surround images of the vehicle while receiving the data transmitted from the LED traffic light. This paper introduces the VLC system we are working on.

  304. What Visible Light Communication (VLC)can do, what VLC cannot do. What I found from the research on VLC using LED array and High-Speed Camera Reviewed

    YAMAZATO Takaya

    IEICE technical report   Vol. 111 ( 94 ) page: 85 - 90   2011.6

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We are conducting a study on visible light communications (VLC) using an LED traffic light and a high-speed camera equipped in a vehicle. Since we use the camera, we can capture and record surround images of the vehicle while receiving the data transmitted from the LED traffic light. This paper introduces the VLC system we are working on.

    CiNii Article

  305. Optimizing Gaussian Pulse Shape of BFDM to Reduce ISI/ICI in Highly Mobile Environments Reviewed

    GOTO Daisuke, YAMAZATO Takaya, MONGOL Bayarpurev

    IEICE technical report   Vol. 111 ( 94 ) page: 221 - 226   2011.6

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In highly mobile environments assumed time-frequency dispersive channels, reducing intersymbol interference(ISI) and intercarrier interference (ICI) depends on the signal pulse shape. Biorthogonal Frequency Division Multiplexing (BFDM) is an efficient modulation in terms of designing pulses flexibly. So BFDM can use Gaussian pulse which is a time-frequency well localized. However, the Gaussian pulse shape is not optimized in every channel. In this paper, we optimize the Gaussian pulse shape against the channels by maximizing the ratio of the ambiguity function of the pulses. Numerical result show that the proposed method is effective for the optimization of the Gaussian pulse shape.

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  306. Erasure coding for road-to-vehicle visible light communication systems Reviewed

    Okada H.

    2011 IEEE Consumer Communications and Networking Conference, CCNC'2011     page: 75 - 79   2011.6

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    DOI: 10.1109/CCNC.2011.5766593

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  307. [Tutorial] Visible Light Communications Invited Reviewed

    T. Yamazato, S. Haruyama

    IEEE International Conference on Communications     page: CD-ROM   2011.6

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    Visible light communications (VLC) is the latest optical wireless communications technologies that uses low-power light emitting diodes, or LEDs, not only to provide light but also to broadcast data. LEDs are extremely energy-efficient and predicted to become widespread in general lighting application. It is expected that LED market will reach $29 billion in 2017 that is comparable to today's NAND and DRAM markets [1]. Because LED is a solid-state lighting device, it can be modulated at high-speed compared with other lighting sources. VLC uses LEDs, which send data by flashing light at speeds undetectable to the human eye.

    The pioneer of VLC using LEDs is Professor Masao Nakagawa of Keio University. His first paper on this subject appeared in the early 2000, together with his successor Prof. Shinichiro Haruyama, the instructor of this tutorial. Later in 2003, he formed Visible Light Communication Consortium (VLCC). Now VLCC is lead by Prof. Haruyama. Please see the following video, an interview of Prof. Haruyama about VLC, which has been broadcast by NHK World in June 4, 2009. http://www.naka-lab.jp/movie/nhk_world.wmv

    So far various experimental VLC systems and prototypes are demonstrated. Such includes 4.8kbps visible light ID as an infrastructure to mobile-terminal application, independent sound transmission through RGB visible lights and 100Mbps VLC wireless LAN system. Using LED array, the data rate of 1 Gbps achieved by Keio University (Prof. Haruyama) that is the fastest at the moment [1]. In terms of longer range, there has been a demonstration by VLCC that achieved 1kbps transmission of the distance 2km, that is the world's longest distance for VLC. Samsung and ETRI are also active in developing VLC applications. They have demonstrated 120Mbps full duplex mobile-to-mobile transmission and 100Mbps signboard transmission. Please see the following video of Nakagawa lab. http://www.youtube.com/watch?v=QEh5f49LsB4

    Widespread use of LEDs in traffic applications and growing interest in Intelligent Transport System (ITS) presents an opportunity for VLC. Data transmission using LED traffic lights, LED road illumination, and LED brake lights are typical application. Dr. Yamazato, the instructor of this tutorial, is a leader in VLC application to ITS and he recently achieved 16kbps data transmission and distance up to 70m in a driving situation with a vehicle moving with 30km/h. Today VLC using LED is a hot topic and VLC projects have been initiated in Europe and US. In 2006 Siemens launched VLC project. Later in 2008, European Commission established OMEGA project with a consortium of 20 European partners from industry and the scientific community [3]. Meanwhile, in 2008, the US National Science Foundation has approved a grant of $18.5 million to help establish and the Engineering Research Center focuses on VLC. The members of the Center include the Rensselaer Polytechnic Institute in New York, Boston University and the University of New Mexico. The University of California also have launched five-year research project called the Ubiquitous Communication by Light (UC-Light) that is founded with $3.5 million from the University. The project is anticipated to begin in 2009 and run for five years.

    VLC is in the process of standardization by the IEEE 802.15 TG7 and VLCC as well as other standard organizations. The first VLC specification standard was released from JEITA in conjunction with VLCC in 2007. Later in 2008, VLCC released their first specification standard adopting and expanding the IrDA physical layer. IrDA transceiver transmission wavelength (IrDA physical layer) is expanded to accommodate the visible light wavelength. By adapting this specification, the existing IrDA optical modules can be used for VLCC data transmission with slight modification. In January 2009, IEEE 802.15 (Wireless Personal Area Networks) Task Group 7 (Visible Light Communication) has been launched. At the 6th meeting held in November 2009 they adopted the baseline draft text for the development of the 802.15.7 standard.

    The goal of this tutorial is to introduce current VLC technology and its trends. Starting with an overview of VLC, participants will learn basics of VLC, on-going standardization activities and VLC. We will provide some experimental results and furthermore detail to enhance VLC application.

  308. Visible Light Communication and its application to ITS Invited

    T. Yamazato

    OBN     page: -   2011.6

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  309. Road-to-Vehicle Visible Light Communication using LED array and on-vehicle high-speed camera Invited

    T. Yamazato

    Technical Report of IEICE   Vol. AN2011-5   page: 21-26   2011.5

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  310. Dynamic Resource Allocation for Improvement of Spectrum Efficiency of Satellite Terrestrial Integrated Mobile Communication System Reviewed

    T. Aman, T. Yamazato

    IEICE Transactions on Communications   Vol. J94-B ( 3 ) page: 373-382   2011.3

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  311. TDOA UWB Positioning with Three Receivers Using Known Indoor Features Reviewed

    J. Kietlinski-Zaleski, T. Yamazato

    IEICE Transactions on Fundamentals   Vol. E94-A ( 3 ) page: 964-971   2011.3

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    Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal 3D Time Difference of Arrival (TDOA) positioning, at least four receivers with an unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel method for TDOA positioning using only three receivers is presented. TDOA positioning with three receivers is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, for example ceiling and walls. The proposed method was verified using data from a measurement campaign.

  312. LED Traffic Light Detection Using High-speed-camera Image Processing for Visible Light Communication System Reviewed

    H. C. N, Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto

    The Journal of the Institute of Television Engineers of Japan   Vol. 65 ( 3 ) page: 354 - 360   2011.3

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    DOI: 10.3169/itej.65.354

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  313. Dynamic Resource Allocation for Improvement of Spectrum Efficiency of Satellite/Terrestrial Integrated Mobile Communication System Reviewed

    AMAN Tomohiro, YAMAZATO Takaya

    The IEICE transactions on communications B   Vol. 94 ( 3 ) page: 373 - 382   2011.3

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  314. TDOA UWB Positioning with Three Receivers Using Known Indoor Features Reviewed

    Jan Kietlinski-Zaleski, Takaya Yamazato

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   Vol. E94A ( 3 ) page: 964 - 971   2011.3

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    Publishing type:Research paper (scientific journal)   Publisher:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal 3D Time Difference of Arrival (TDOA) positioning, at least four receivers with an unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel method for TDOA positioning using only three receivers is presented. TDOA positioning with three receivers is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, for example ceiling and walls. The proposed method was verified using data from a measurement campaign.

    DOI: 10.1587/transfun.E94.A.964

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  315. Optimization of gaussian pulse using ambiguity function in Biorthogonal Frequency Division Multiplexing (BFDM)

    D. Goto, T. Yamazato, B. Mongol

    IEICE General Conference   Vol. B-5-28   page: 414   2011.2

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  316. A note on turbo compression and joint error correction of temporally and spatially correlated sources

    K. Kobayashi, T. Yamazato, M. Katayama

    IEICE General Conference   Vol. B-20-15   page: 610   2011.2

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  317. Channel model for Road to Vehicle Visible Light Communication System using LED Array and High-Speed Camera

    T. Ozawa, T. Nagura, T. Yamazato, T. Yendo, T.Fujii, H. Okada

    IEICE General Conference   Vol. A-17-6   page: 252   2011.2

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  318. B-20-15 A note on turbo compression and joint error correction of temporally and spatially correlated sources Reviewed

    KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    Proceedings of the IEICE General Conference   Vol. 2011 ( 2 )   2011.2

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  319. B-5-28 Optimization of gaussian pulse using ambiguity function in Biorthogonal Frequency Division Multiplexing (BFDM) Reviewed

    GOTO Daisuke, YAMAZATO Takaya, MONGOL Bayarpurev

    Proceedings of the IEICE General Conference   Vol. 2011 ( 1 )   2011.2

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  320. A-17-6 Channel model for Road to Vehicle Visible Light Communication System Reviewed

    OZAWA Toshiyuki, NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    Proceedings of the IEICE General Conference   Vol. 2011   2011.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  321. High-Speed LED Traffic Sign Tracking Method Using Image Sensor with High-Speed Capturing Ability of Partial Area

    K. Maeno, T. Yendo, M. P. Tehrani, T. Fujii, T. Yamazato, H. Okada, M. Tanimoto

    Technical Report of IEICE   Vol. ITS2010-41   page: 101-106   2011.2

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  322. Overlay Coding for Visible Light Communication using LED Array and High-Speed Camera

    S. Nishimoto, T. Nagura, T. Yamazato, T. Yendo, T. Fujii, H. Okada, S. Arai

    Technical Report of IEICE   Vol. ITS2010-39   page: 89-94   2011.2

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  323. Performance Improvement with the Inverted Signal to Track an LED Array Transmitter on Road-to-Vehicle Visible Light Communications

    T. Nagura, T. Yamazato, T. Yendo, T. Fujii, H. Okada

    Technical Report of IEICE   Vol. ITS2010-40   page: 95-99   2011.2

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  324. Overlay Coding for Visible Light Communication using LED Array and High-Speed Camera Reviewed

    NISHIMOTO Sayaka, NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku, ARAI Shintaro

    IEICE technical report   Vol. 110 ( 420 ) page: 89 - 94   2011.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we discuss on visible light communications using an LED array as the transmitter and a highspeed camera as the receiver. A challenge is that the longer the distance between the transmitter and the receiver, the more reduction in the resolution of the receive image occurs. To solve the problem, we allocate high priority data to low frequency components of spatial frequency. Then, we can receive high priority data even if the receiver is far from the transmitter. For that, we have used the Wavelet transform in our previous researches. However, the conventional scheme limits the number and the disposition of LEDs which can be allocated data. In other words, the hierarchical coding using the Wavelet transform has a low degree of freedom of design. In this paper, to improve a degree of freedom of design, we propose the overlay coding which does not limit the number and the disposition of LEDs.

    CiNii Article

  325. Performance Improvement with the Inverted Signal to Track an LED Array Transmitter on Road-to-Vehicle Visible Light Communications Reviewed

    NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report   Vol. 110 ( 420 ) page: 95 - 99   2011.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we consider road-to-vehicle visible light communication systems on driving situation using a LED array transmitter and a high-speed camera receiver. In our previous research, we have proposed inverted signal to track an LED array transmitter. We propose decoding method with inverted signal to improve BER performance. Furthermore, we confirm that we can suppress the flicker of LED in PDF.

    CiNii Article

  326. Performance Improvement with the Inverted Signal to Track an LED Array Transmitter on Road-to-Vehicle Visible Light Communications Reviewed

    NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report   Vol. 110 ( 421 ) page: 95 - 99   2011.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we consider road-to-vehicle visible light communication systems on driving situation using a LED array transmitter and a high-speed camera receiver. In our previous research, we have proposed inverted signal to track an LED array transmitter. We propose decoding method with inverted signal to improve BER performance. Furthermore, we confirm that we can suppress the flicker of LED in PDF.

    CiNii Article

  327. Overlay Coding for Visible Light Communication using LED Array and High-Speed Camera Reviewed

    NISHIMOTO Sayaka, NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku, ARAI Shintaro

    IEICE technical report   Vol. 110 ( 421 ) page: 89 - 94   2011.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we discuss on visible light communications using an LED array as the transmitter and a highspeed camera as the receiver. A challenge is that the longer the distance between the transmitter and the receiver, the more reduction in the resolution of the receive image occurs. To solve the problem, we allocate high priority data to low frequency components of spatial frequency. Then, we can receive high priority data even if the receiver is far from the transmitter. For that, we have used the Wavelet transform in our previous researches. However, the conventional scheme limits the number and the disposition of LEDs which can be allocated data. In other words, the hierarchical coding using the Wavelet transform has a low degree of freedom of design. In this paper, to improve a degree of freedom of design, we propose the overlay coding which does not limit the number and the disposition of LEDs.

    CiNii Article

  328. High-Speed LED Traffic Sign Tracking Method Using Image Sensor with High-Speed Capturing Ability of Partial Area Reviewed

    MAENO Keita, YENDO Tomohiro, PANAHPOUR TEHRANI Mehrdad, FUJII Toshiaki, YAMAZATO Takaya, OKADA Hiraku, TANIMOTO Masayuki

    IEICE technical report   Vol. 110 ( 420 ) page: 101 - 106   2011.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Visible Light Communication(VLC) using LEDs has been proposed as a wireless communication method. As an application of VLC in ITS, we propose a road-to-vehicle visible light communication system using an LED traffic sign as a transmitter and an image sensor as a receiver. For conducting the communication, it is necessary to have high-speed tracking of the LED traffic sign by the image sensor. In this paper, we propose new high-speed tracking method for this system.

    CiNii Article

  329. High-Speed LED Traffic Sign Tracking Method Using Image Sensor with High-Speed Capturing Ability of Partial Area Reviewed

    MAENO Keita, YENDO Tomohiro, PANAHPOUR TEHRANI Mehrdad, FUJII Toshiaki, YAMAZATO Takaya, OKADA Hiraku, TANIMOTO Masayuki

    IEICE technical report   Vol. 110 ( 421 ) page: 101 - 106   2011.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Visible Light Communication(VLC) using LEDs has been proposed as a wireless communication method. As an application of VLC in ITS, we propose a road-to-vehicle visible light communication system using an LED traffic sign as a transmitter and an image sensor as a receiver. For conducting the communication, it is necessary to have high-speed tracking of the LED traffic sign by the image sensor. In this paper, we propose new high-speed tracking method for this system.

    CiNii Article

  330. Channel Estimator by Sum of Kalman-Based Estimation and Interpolation Estimation for MC-CDMA based Inter-Vehicle Communication Reviewed

    H. Hiraiwa, T. Yamazato, M. Katayama

    IEICE Transactions on Communications   Vol. J94-B ( 2 ) page: 304-307   2011.2

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    In Satellite Terrestrial Integrated Mobile Communication System, a single mobile terminal can communicate to both satellite and terrestrial communication systems depend upon his location, QoS and availability of resources among satellite and terrestrial communication systems. But it is hard to achieve high spectrum efficiency of Satellite Terrestrial Integrated Mobile Communication System using fixed resource allocation schemes because variation of satellite traffic and terrestrial traffic is different.

  331. LED Traffic Light Detection Using High-speed-camera Image Processing for Visible Light Communication System, Reviewed

    H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto

    The Journal of the Institute of Television Engineers of Japan   Vol. 65 ( 3 ) page: 354-360   2011.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    We propose a visible light road-to-vehicle communication system at intersection as an ITS (Intelligent Transport System) technique. In this system, the communication between a vehicle and an LED traffic light is conducted using an LED traffic light as a transmitter and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light at high frequency, and those emitted light is captured by the high-speed camera for communications. Here, the luminance value of the LEDs in the transmitter should be found, and then it should be tracked in consecutive frames while the vehicle is moving by processing the images from the high-speed camera. In this paper, we propose new algorithms for finding and tracking the transmitter, which result in increased communication speed and data rate compared to the previous methods. Experiments using appropriate images showed the effectiveness of the proposals.

  332. Channel Estimator by Sum of Kalman-Based Estimation and Interpolation Estimation for MC-CDMA Based Inter-Vehicle Communication Reviewed

    HIRAIWA Noriaki, YAMAZATO Takaya, KATAYAMA Masaaki

    The IEICE transactions on communications B   Vol. 94 ( 2 ) page: 304 - 307   2011.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  333. Improvement of the Node Activity Rate by Introduction of New Inactive Node Reactivation Condition in Solar-Powered Wireless Sensor Networks Reviewed

    K. Ota, K. Kobayashi, T. Yamazato, M. Katayama

    Technical Report of IEICE   Vol. USN2010-63   page: 137-142   2011.1

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  334. Improvement of the Node Activity Rate by Introduction of New Inactive Node Reactivation Condition in Solar-Powered Wireless Sensor Networks Reviewed

    OTA Kentaro, KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 110 ( 378 ) page: 137 - 142   2011.1

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Our goal is improvement of the node activity rate in solar-powered wireless sensor networks. One method to reduce the consumption energy of the entire network is a cooperative transmission that uses a relay node when a node sends data. But if we don't consider the change in harvesting energy, the node activity rate is declined during nighttime. In this paper, we smooth the day-and-night node activity rate by introducing the new inactive node reactivation condition and achieve the required high node activity rate.

    CiNii Article

  335. Erasure Coding for Road-to-Vehicle Visible Light Communication Systems Reviewed

    H. Okada, T. Ishizaki, T. Yamazato, T. Yendo, T. Fujii

    IEEE Intelligent Vehicular Communications System Workshop     page: 970-974   2011.1

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    In this paper, we focus on a road-to-vehicle visible light communication (VLC) system using LED traffic lights. In this system, an LED traffic light consists of a 2-dimensional LED array (2D LED array), and cars are equipped with high-speed 2-dimensional cameras (2D image sensors). An important issue of this system is frame loss. Sometimes, 2D image sensor in a car fails to get a frame. So as to mitigate the influence of frame loss, we propose to apply erasure coding to the road-to-vehicle VLC system. In the proposed system, a data sequence is encoded by LDPC code whose length is much longer than the size of 2D LED array. In addition, code synchronization is required for the proposed system. We also propose a code synchronization scheme, which makes use of error detection capability of LDPC code. We evaluate the performance of our proposed system, and show that it can recover frame loss for high SNR when less than 8 frames among total 18 frames are lost. In addition, we show that our proposed code synchronization scheme can ignore its errors.

  336. Hierarchical Encoding System of Road-to-Vehicle Communication Reviewed

    T. Masuda, T. Yendo, T. Yamazato, H. Okada, M. P. Tehrani, T. Fujii, M. Tanimoto

    International Workshop on Advanced Image Technology (IWAIT2011)     page: CD-ROM   2011.1

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    In this paper, we propose the new visible light road-to-vehicle communication system. We use the LED traffic light as the transmitter and the high-speed camera on the vehicle as the receiver. In this system, the data is encoded hierarchically and assign with the each frequency components of the image. We use the DFT for hierarchical encoding considering channel characteristic and quantization of the luminance. The communication experiments were conducted to confirm the effectiveness of the proposed method.

  337. Parallel Communication Using Visually Non-Lighting LEDs Reviewed

    K. Maeno, T. Yendo, M. P. Tehrani, T. Fujii, H. Okada, T. Yamazato, M. Tanimoto

    International Workshop on Advanced Image Technology (IWAIT2011)     page: CD-ROM   2011.1

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    Previous studies on visible light communication uses visually lighting LEDs. However, LEDs are not always lighting. In this paper, we propose visible light communication method using visually non-lighting LEDs. This method enables us to communicate in different situations, e.g. using visually non-lighting tail lamps of cars or visually non-lighting traffic lights. We realize visually non-lighting LEDs by reducing luminescence energy of LEDs according to the brightness in the environment. To reduce luminescence energy of LEDs, we reduce the number of emitting LEDs, increase the interval of emitting, and decrease the luminance of emitting LEDs. In our research we consider the case that the transmitter is tail lamps of cars and the receiver is high-speed camera. We conduct two types of experiments to demonstrate the performance of the proposed system. One is to confirm that LEDs are visually non-lighting. The other is measurement of Bit Error Rate of communication using visually non-lighting LEDs. Experimental results demonstrate that it is possible to make communication using visually non-lighting LEDs. In our future work, we plan to use different sensor devices such as photo diode or CCD in order to decrease the error rate in communication.

  338. Image Processing Based Road-to-vehicle Visible Light Communication Reviewed

    H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamasato, H. Okada, T. Fujii, M. Tanimoto

    International Workshop on Advanced Image Technology (IWAIT2011)     page: CD-ROM   2011.1

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    Visible Light Communication(VLC) has been introduced as a new wireless communication method. In this paper, we propose a VLC system for Intelligent Transport System (ITS) to communicate between infrastructure and the vehicle. In this system, we use a LED array as a transmitter and on-vehicle high speed camera as a receiver. Here, LEDs in the transmitter emit light in 500Hz and the emission patterns are used to achieve communication, by capturing them using the high speed camera in high frame rate. The images captured by high speed camera are processed to find the transmitter, track the found transmitter, and capture the emission pattern of transmitter in consecutive frames. In our previous work, we proposed algorithms to finding and tracking. In this paper, we introduce method to capture the emission pattern of the transmitter. Then out door communication experiments were conducted to confirm the effectiveness of the proposed VLC system.

  339. 9-217 Messages provided by a teacher that can be read from the Nagoya Univeristy OCW Reviewed

    Yamazato Takaya

    Proceedings of Annual Conference of Japanese Society for Engineering Education   Vol. 2011 ( 0 ) page: 440 - 441   2011

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    Publishing type:Research paper (scientific journal)   Publisher:Japanese Society for Engineering Education  

    DOI: 10.20549/jseeja.2011.0_440

    CiNii Article

  340. Cooperative Transmission Scheme with Inactive Node Reactivation Condition for Solar-Powered Wireless Sensor Networks Reviewed

    Ota Kentaro, Kobayashi Kentaro, Yamazato Takaya, Katayama Masaaki

    2011 IEEE 22ND INTERNATIONAL SYMPOSIUM ON PERSONAL INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC)     page: 2384 - 2388   2011

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    Web of Science

  341. Cooperative Transmission Scheme with Inactive Node Reactivation Condition for Solar-Powered Wireless Sensor Networks Reviewed

    Kentaro Ota, Kentaro Kobayashi, Takaya Yamazato, Masaaki Katayama

    2011 IEEE 22ND INTERNATIONAL SYMPOSIUM ON PERSONAL INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC)     page: 2384 - 2388   2011

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    Our goal is the improvement of the node activity rate in solar-powered wireless sensor networks. We consider the application of a cooperative transmission scheme that uses a relay node when a node sends data to reduce the consumption of energy of the entire network. However, if we do not consider the variations in energy harvesting, the node activity rate declines during nighttime. In this paper, we smooth out the day-and-night node activity rate variations by introducing the new inactive node reactivation condition and achieve the required high node activity rate.

    DOI: 10.1109/PIMRC.2011.6139948

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    Scopus

  342. LED Traffic Light Detection Using High-speed-camera Image Processing for Visible Light Communication Reviewed

    Premachandra H. Chinthaka N., Yendo Tomohiro, Tehrani Mehrdad Panahpour, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Tanimoto Masayuki

    Information and Media Technologies   Vol. 6 ( 3 ) page: 785 - 791   2011

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    Publishing type:Research paper (scientific journal)   Publisher:Information and Media Technologies 編集運営会議  

    We propose a visible light road-to-vehicle communication system at intersections as an ITS(Intelligent Transport System) technique. In this system, the communication between a vehicle and an LED traffic light is conducted using an LED traffic light as a transmitter and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light at high frequency, and those emitted light is captured by the high-speed camera for communication. Here, the luminance value of the LEDs in the transmitter should be captured in consecutive frames to achieve communication. For this purpose, first the transmitter should be found, and then it should be tracked in consecutive frames while the vehicle is moving by processing the images from the high-speed camera. In this paper, we propose new algorithms for finding and tracking the transmitter, which result in increased communication speed and data rate compared to the previous methods. Experiments using appropriate images showed the effectiveness of the proposals.

    DOI: 10.11185/imt.6.785

    CiNii Article

  343. Overlay Coding for Visible Light Communication using LED Array and High-Speed Camera Reviewed

    NISHIMOTO Sayaka, NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku, ARAI Shintaro

    ITE Technical Report   Vol. 35 ( 0 ) page: 89 - 94   2011

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    In this paper, we discuss on visible light communications using an LED array as the transmitter and a highspeed camera as the receiver. A challenge is that the longer the distance between the transmitter and the receiver, the more reduction in the resolution of the receive image occurs. To solve the problem, we allocate high priority data to low frequency components of spatial frequency. Then, we can receive high priority data even if the receiver is far from the transmitter. For that, we have used the Wavelet transform in our previous researches. However, the conventional scheme limits the number and the disposition of LEDs which can be allocated data. In other words, the hierarchical coding using the Wavelet transform has a low degree of freedom of design. In this paper, to improve a degree of freedom of design, we propose the overlay coding which does not limit the number and the disposition of LEDs.

    DOI: 10.11485/itetr.35.9.0_89

    CiNii Article

  344. Performance Improvement with the Inverted Signal to Track an LED Array Transmitter on Road-to-Vehicle Visible Light Communications Reviewed

    NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    ITE Technical Report   Vol. 35 ( 0 ) page: 95 - 99   2011

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    In this paper, we consider road-to-vehicle visible light communication systems on driving situation using a LED array transmitter and a high-speed camera receiver. In our previous research, we have proposed inverted signal to track an LED array transmitter. We propose decoding method with inverted signal to improve BER performance. Furthermore, we confirm that we can suppress the flicker of LED in PDF.

    DOI: 10.11485/itetr.35.9.0_95

    CiNii Article

  345. Overlay Coding for Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera Reviewed

    Nishimoto Sayaka, Nagura Toru, Yamazato Takaya, Yendo Tomohiro, Fujii Toshiaki, Okada Hiraku, Arai Shintaro

    2011 14TH INTERNATIONAL IEEE CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC)     page: 1704 - 1709   2011

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    Web of Science

  346. Overlay Coding for Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera Reviewed

    Sayaka Nishimoto, Toru Nagura, Takaya Yamazato, Tomohiro Yendo, Toshiaki Fujii, Hiraku Okada, Shintaro Arai

    2011 14TH INTERNATIONAL IEEE CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC)     page: 1704 - 1709   2011

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This paper aims to improve the visible light communication system using LED array and high-speed camera by proposing what we call "overlay coding". "Overlay coding" is a new coding method to realize a hierarchical coding, through which a high-priority data can be received even if the receiver is far from a transmitter. Conventionally, the hierarchical coding has been realized through the wavelet transform that has a limitation of number and disposition of LEDs, and as a result it does not always match with the design of the transmitters (e.g. traffic lights, etc.) used in real life. To solve the limitation problem, we propose a more flexible way of designing the application of LEDs depending on the transmitters. In particular, overlay coding is realized through the procedures of coding and decoding. In coding, we replace one LED with a flexible number of LEDs, and the number depends on whether the data is high-priority or low-priority, then high-priority data and low-priority data are overlaid (section III-B1). In decoding, we first obtain the high-priority data, and then the low-priority data using retrieved high-priority data (section III-B2). The experimental result shows that the distance for receiving error-free data is extended from 30m to 70m in the overlay coding (section IV-B).

    DOI: 10.1109/ITSC.2011.6082943

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    Scopus

  347. High-Speed LED Traffic Sign Tracking Method Using Image Sensor with High-Speed Capturing Ability of Partial Area Reviewed

    MAENO Keita, YENDO Tomohiro, PANAHPOUR TEHRANI Mehrdad, FUJII Toshiaki, YAMAZATO Takaya, OKADA Hiraku, TANIMOTO Masayuki

    ITE Technical Report   Vol. 35 ( 0 ) page: 101 - 106   2011

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    Visible Light Communication (VLC) using LEDs has been proposed as a wireless communication method. As an application of VLC in ITS, we propose a road-to-vehicle visible light communication system using an LED traffic sign as a transmitter and an image sensor as a receiver. For conducting the communication, it is necessary to have high-speed tracking of the LED traffic sign by the image sensor. In this paper, we propose new high-speed tracking method for this system.

    DOI: 10.11485/itetr.35.9.0_101

    CiNii Article

  348. TDOA UWB positioning with three receivers using known indoor features Reviewed

    Kietlinski-Zaleski J.

    2010 IEEE International Conference on Ultra-Wideband, ICUWB2010 - Proceedings   Vol. 2   2010.12

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    Publishing type:Research paper (scientific journal)   Publisher:2010 IEEE International Conference on Ultra-Wideband, ICUWB2010 - Proceedings  

    DOI: 10.1109/ICUWB.2010.5616909

    Scopus

  349. Dynamic Bandwidth Allocation of Satellite/Terrestrial Integrated Mobile Communication System Reviewed

    T. Yamazato, T. Aman, M. Katayama

    IEEE Global Communications Conference     page: CD-ROM   2010.12

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    In this paper, we propose two dynamic bandwidth allocation (DBA) schemes, a game theory based DBA and a successive DBA, for satellite/terrestrial integrated mobile communication system (STICS). The game theory based DBA allocate the bandwidth according to a utility function based on a weighted demand bandwidth of both satellite and terrestrial system. The successive DBA recursively allocates an unit of bandwidth according to a weighted number of bandwidth unfilled cells of both satellite and terrestrial systems, until the total bandwidth is fulfilled. As results, both DBA outperform the conventional fixed bandwidth allocation scheme. Between two proposed DBA, the successive DBA shows better spectral improvement ratio than the game theory based DBA.

  350. LED Traffic Light Detection Using High-speed-camera Image Processing for Visible Light Communication System, Reviewed

    H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto

    Workshop on Picture Coding and Image Processing, PCSJ2010/IMPS2010     page: CD-ROM   2010.12

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    Intelligent transport system has been introduced to reduce traffic problems such traffic accidents and traffic congestions. In this paper, we introduce a receiver for a road to vehicle Visible Light Communication (VLC) system which is proposed as an Intelligent Transport System (ITS) technique. In this system, an on-vehicle high-speed camera is used as a receiver and an LED array is used as a transmitter. VLC is a wireless communication using luminance. Here, transmitter send information by emitting light and receiver receive them by capturing the luminance of emitting LEDs in the array(Luminance: whether each LED is on or off). For capturing the Luminance, it is necessary to find the transmitter and track it in consecutive frames. In our previous works we introduced methods for finding and tracking. In this paper, we shortly explain the proposed transmitter finding and tracking methods and then a new method is proposed for capturing the luminance of LEDs to achieve communication.

  351. Parallel Visible Light Communication Using Visually Non-Lighting LEDs Reviewed

    K. Maeno, T. Yendo, M. P. Tehrani, T. Fujii, T. Yamazato, H. Okada, M. Tanimoto

    Workshop on Picture Coding and Image Processing, PCSJ2010/IMPS2010     page: CD-ROM   2010.12

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    Language:English  

    Our goal is improvement of the node activity rate in solar-powered wireless sensor networks. One method to reduce the consumption energy of the entire network is a cooperative transmission that uses a relay node when a node sends data. But if we do not consider the change in harvesting energy, the node activity rate is declined during nighttime. In this paper, we smooth the day-and-night node activity rate by introducing the new inactive node reactivation condition and achieve the required high node activity rate.

  352. Hierarchical Encoding System for Road-to-Vehicle Communication Using LED Traffic Light Reviewed

    T. Masuda, T. Yendo, T. Yamazato, H. Okada, M. P. Tehrani, T. Fujii, M. Tanimoto

    Workshop on Picture Coding and Image Processing, PCSJ2010/IMPS2010     page: CD-ROM   2010.12

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    Language:English  

    This paper discusses the visible light road-to-vehicle communication system at intersection as one of ITS (Intelligent Transport System) technique. The communication between a vehicle and an LED traffic light is approached using an LED traffic light as a transmitter, and on-vehicle high-speed camera as a receiver. In this system, it is able to send data by blinking the LEDs of the traffic light in two dimensional patterns, and able to receive them by high-speed camera with image processing [1]. Here, we aim to conduct long-distance high-speed visible light communication. When the distance between transmitter and receiver is far, the image of the LED traffic light captured by on-vehicle high-speed camera is very small. So, if the data are put on two dimension patterns without modification, data would be mistaken, because the two dimension patterns can't be realized correctly. To solve this problem, data are encoded hierarchically before they are lighted by the LED traffic light. This is called as hierarchical encoding that the data are assigned with each spatial frequency.

  353. [Encouragement Talk] Distributed Error Correcting Coding and Joint Decoding Scheme Using Spatial Correlation of Sensor ADC Output in Wireless Sensor networks Invited

    K. Kobayashi, T. Yamazato, M. Katayama

    Technical Report of IEICE   Vol. WBS2010-39   page: 23-28   2010.12

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  354. EXIT Analysis for MAP-based Joint Iterative Decoding of Separately Encoded Correlated Sources Reviewed

    K. Kobayashi, T. Yamazato, M. Katayama

    IEICE Transactions on Communications   Vol. E93-B ( 12 ) page: 3509-3513   2010.12

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    We develop a mathematical framework for the extrinsic information transfer (EXIT) analysis to assess the convergence behavior of maximum a posteriori (MAP)-based joint iterative decoding of correlated sources, which are separately encoded and transmitted over noisy channels. Unlike the previous work, side information about the correlation is not perfectly given at the joint decoder but is extracted from decoder output and updated in an iterative manner. The presented framework provides a convenient way to compare between schemes. We show that it allows us to easily and accurately predict joint decoding gain and turbo cliff position.

  355. TOA UWB Positioning with Two Receivers Using Known Indoor Features Reviewed

    J. Kietlinski-Zaleski, T. Yamazato, M. Katayama

    IEICE Transactions on Communications   Vol. E93-B ( 12 ) page: 3624-3631   2010.12

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    Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival (ToA) positioning, at least three receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel algorithm for ToA positioning using only two receivers is presented. This is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, for example ceiling and walls. The proposed algorithm was tested using data from a measurement campaign.

  356. EXIT Analysis for MAP-Based Joint Iterative Decoding of Separately Encoded Correlated Sources Reviewed

    Kentaro Kobayashi, Takaya Yamazato, Masaaki Katayama

    IEICE TRANSACTIONS ON COMMUNICATIONS   Vol. E93B ( 12 ) page: 3509 - 3513   2010.12

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    Publishing type:Research paper (scientific journal)   Publisher:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    We develop a mathematical framework for the extrinsic information transfer (EXIT) analysis to assess the convergence behavior of maximum a posteriori (MAP) based joint iterative decoding of correlated sources which are separately encoded and transmitted over noisy channels Unlike the previous work our approach focuses on the case side information about the correlation is not perfectly given at the joint decoder but is extracted from decoder output and updated in an iterative manner The presented framework provides a convenient way to compare between schemes We show that it allows us to easily and accurately predict Joint decoding gain and turbo cliff position

    DOI: 10.1587/transcom.E93.B.3509

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  357. Recent Advances in Satellite and Space Communications Reviewed

    Bisio Igor, De Gaudenzi Riccardo, Nguyen Hung, Pavlidou Fotini-Niovi, Yamazato Takaya

    JOURNAL OF COMMUNICATIONS AND NETWORKS   Vol. 12 ( 6 ) page: 523 - 528   2010.12

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  358. Recent Advances in Satellite and Space Communications Reviewed

    Igor Bisio, Riccardo De Gaudenzi, Hung Nguyen, Fotini-Niovi Pavlidou, Takaya Yamazato

    JOURNAL OF COMMUNICATIONS AND NETWORKS   Vol. 12 ( 6 ) page: 523 - 528   2010.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:KOREAN INST COMMUNICATIONS SCIENCES (K I C S)  

    DOI: 10.1109/JCN.2010.6388298

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  359. TOA UWB Positioning with Two Receivers Using Known Indoor Features Reviewed

    Jan Kietlinski-Zaleski, Takaya Yamazato, Masaaki Katayama

    IEICE TRANSACTIONS ON COMMUNICATIONS   Vol. E93B ( 12 ) page: 3624 - 3631   2010.12

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    Publishing type:Research paper (scientific journal)   Publisher:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    Ultra Wideband is an attractive technology for short range positioning especially Indoors However for normal Time of Arrival (ToA) positioning at least three receivers with unblocked direct path to the trans miner are required A requirement that is not always met In this work a novel algorithm for ToA positioning using only two receivers is presented This is possible by exploiting the knowledge of some of the indoor features namely positions of big flat reflective surfaces for example ceiling and walls The proposed algorithm was tested using data from a measurement campaign

    DOI: 10.1587/transcom.E93.B.3624

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  360. UWB positioning using known indoor features- Environment comparison Reviewed

    Kietlinski-Zaleski J.

    2010 International Conference on Indoor Positioning and Indoor Navigation, IPIN 2010 - Conference Proceedings     2010.12

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    Publishing type:Research paper (scientific journal)   Publisher:2010 International Conference on Indoor Positioning and Indoor Navigation, IPIN 2010 - Conference Proceedings  

    DOI: 10.1109/IPIN.2010.5648089

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  361. Distributed Error Correcting Coding and Joint Decoding Scheme Using Spatial Correlation of Sensor ADC Output in Wireless Sensor networks Reviewed

    KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 110 ( 326 ) page: 23 - 28   2010.11

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    In wireless sensor networks, sensor nodes are densely deployed for reliable sensing of physical phenomenon. Due to the high density in the sensing field, sensor observations are spatially correlated. In this paper, we focus on joint channel decoding utilizing the spatial correlation of multiple sensor observations. Our proposed scheme makes use of an estimation of the correlation according to ADC bit levels. In addition, the proposed scheme makes use of Gray code for avoiding multiple bit-flipping between adjacent ADC output values. The performance of our approach is examined by simulations using sensor data from experiments in a real indoor environment.

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  362. Experimental Results on Simple Distributed Cooperative Transmission Scheme with Visible Light Communication Reviewed

    T. Yamazato, K. Nakao, H. Okada, M. Katayama

    IEICE Transactions on Communications   Vol. E93-B ( 11 ) page: 2959-2962   2010.11

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    We consider a distributed transmission of data packet to a sink where the distance of a sensor node to a sink is much longer than the maximum communication range of each sensor node. We give a simple modification to the transmitter, i.e., multiplication of random phase before the transmission. Thanks to Turbo Code, it is possible to extend the trans- mission range as the received amplitude varies symbol by symbol for our scheme while whole data packet may be lost for the conventional scheme. In this letter, we report the experimental results of our scheme equivalently developed using visible light communication.

  363. Experimental Results on Simple Distributed Cooperative Transmission Scheme with Visible Light Communication Reviewed

    Takaya Yamazato, Koji Nakao, Hiraku Okada, Masaaki Katayama

    IEICE TRANSACTIONS ON COMMUNICATIONS   Vol. E93B ( 11 ) page: 2959 - 2962   2010.11

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    We consider a distributed transmission of data packet to a sink where the distance of a sensor node to a sink is much longer than the maximum communication range of each sensor node We give a simple modification to the transmitter i e multiplication of random phase before the transmission Thanks to Turbo Code it is possible to extend the trans mission range as the received amplitude vanes symbol by symbol for our scheme while whole data packet may be lost for the conventional scheme In this letter we report the experimental results of our scheme equivalently developed using visible light communication

    DOI: 10.1587/transcom.E93.B.2959

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  364. Performance evaluation of the cognitive piggyback overlay systems with dirty paper coding Reviewed

    J. Naganawa, K. Kobayashi, M. Katayama, T. Yamazato

    10th International Symposium on Communications and Information Technologies (ISCIT2010)   Vol. FA1-1-4   page: 974-979   2010.10

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    This manuscript considers a secondary system sharing the spectrum with the primary system at the same time and on the same frequency. We propose a cognitive overlay system in which the secondary system relays the primary signal and piggybacks its own data on it. Furthermore, the secondary system uses the channel coding based on the dirty paper coding (DPC). The result of the analysis shows that the proposed scheme allows the secondary system to communicate at the same speed as the primary system without any harm to it.

  365. Improvement of Sequential-Test-Based Cooperative Spectrum Sensing Systems in Band Limited Control Channels Reviewed

    S. Mitsuya, K. Kobayashi, T. Yamazato, M. Katayama

    10th International Symposium on Communications and Information Technologies (ISCIT2010)   Vol. FA1-1-3   page: 968-973   2010.10

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    In a cooperative spectrum sensing system, many nodes perform spectrum sensing and report their decisions to one fusion center via control channels. This paper considers efficient use of the frequency band for the control channels. For this purpose, sequential-test is introduced for the local decision at each node. With this scheme, the transmission timing of the reports from the nodes becomes at random and necessary maximum bandwidth for the control channels decreases. Numerical results show that this sequential-test-base-scheme not only decreases the number of simultaneous reports but also improves sensing reliability. For further improvement, this paper also introduces a decision scheme at the fusion center based on probabilistic features of the reports from the nodes.

  366. Inband and Outband Spectrum Analysis of the BFDM and BFDM/OQAM Signals with Truncated Gaussian Pulses Reviewed

    B. Mongol, T. Yamazato, M. Katayama

    International Symposium on Information Theory and Its Applications     page: CD-ROM   2010.10

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    Pulse-shaping OFDM, or more generally BFDM and BFDM/OQAM, systems are originally proposed to combat inter- carrier interference (ICI) caused by time-variance of the channel. The main property that makes these signals robust against ICI is that they allow to employ time-frequency well localized pulses, particularly Gaussian pulse which has the best time-frequency localization. However, this property also suppresses the outband or inband spectral leakage of the BFDM and BFDM/OQAM signal, making them attractive physical layer modulation scheme for cognitive radio. In this paper we analyze the power density spectra of the BFDM and BFDM/OQAM signals and numerically evaluate the inband and outband spectra for truncated Gaussian pulses.

  367. Error-correcting scheme based on chaotic dynamics and its performance for noncoherent chaos communications Reviewed

    S. Arai, Y. Nishio and T. Yamazato

    NOLTA, IEICE   Vol. 1 ( 1 ) page: 196-206   2010.10

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    This paper proposes a novel error-correcting scheme using chaotic dynamics for noncoherent chaos communications. In our proposed system, two successive chaotic sequences are generated from the same chaotic map; the second sequence is generated with an initial value which is the last value of the first sequence. In this case, successive chaotic sequences having the same chaotic dynamics are created. This feature gives the receiver additional information to correctly recover the information data and thus improves the bit error performance of the receiver. As results of the computer simulation, we confirm that the advantage gained in BER performance of the proposed error-correcting method is about 1-1.5 dB compared to conventional method. In addition, we achieve that the proposed error-correcting scheme is performed without the new additional redundancy code by using the chaotic dynamics.

  368. Kalman Channel Estimator for BFDM/OQAM system in Time-Frequency Dispersive Channels Reviewed

    B. Mongol, T. Yamazato, M. Katayama

    IEICE Transactions on Communications   Vol. J93-B ( 10 ) page: 1466-1480   2010.10

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    Biorthogonal Frequency Division Multiplexing / Offset QAM (BFDM/OQAM) allows to employ a Gaus- sian transmitter pulse. Thus, it performs well in the time-frequency dispersive channels as it can suppress ISI and ICI without having guard interval. However, in the highly mobile environment the performance deteriorates and channel estimation schemes became essential for further improvement of BFDM/OQAM systems. This paper proposes a novel adaptive channel estimator based on Kalman filter. Especially, we derive the essential equations to design Kalman filter, namely, the process equation and the measurement equation.

  369. Kalman Channel Estimator for BFDM/OQAM System in Time-Frequency Dispersive Channels Reviewed

    MONGOL Bayarpurev, YAMAZATO Takaya, KATAYAMA Masaaki

    The IEICE transactions on communications B   Vol. 93 ( 10 ) page: 1466 - 1480   2010.10

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  370. A Study on Joint Channel Decoding Using Spatial Correlation of Sensor Observations According to ADC Bit levels Reviewed

    K. Kobayashi, T. Yamazato, M. Katayama

    IEEE International Workshop on Wireless Distributed Networks (WDN2010)     page: 484-489   2010.9

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    In densely deployed wireless sensor networks, observations of the sensor nodes are spatially correlated. In this paper, we study a joint channel decoding scheme utilizing bit correlation of the sensor observations according to bit levels of analog-digital converter (ADC). If sensor ADC output is interpreted as natural binary numeral, carry propagation may occur between adjacent ADC output values. Such carry propagation leads to the degradation of joint decoding gain. We focus on the use of Gray code for avoiding the carry propagation. The performance of our approach is demonstrated by simulations using sensor data from experiments in a real indoor environment.

  371. TDOA UWB Positioning with Three Receivers Using Known Indoor Features Reviewed

    J. Kietlinski-Zaleski, T. Yamazato, M. Katayama

    2010 IEEE International Conference on Ultra-Wideband     page: CD-ROM   2010.9

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    Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal 3D Time Difference of Arrival (TDoA) positioning, at least four receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel method for TDoA positioning using only three receivers is presented and tested using real-world measurements. Positioning with three receivers is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, reflectors, for example ceiling and walls.

  372. Tracking an LED Array Transmitter for Visible Light Communications in the Driving Situation Reviewed

    T. Nagura, T. Yamazato, M. Katayama, T. Yendo, T. Fujii, H. Okada

    IEEE International Symposium on Wireless Communication Systems (ISWCS2010)     page: 765-769   2010.9

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    In this paper, we discuss on a decoding algorithm for visible light communication systems in the driving situation using an LED array transmitter and a high-speed camera receiver. We propose an LED array detection method using M-sequence and an LED array tracking method using inverted signals. We confirm that we can distinguish LED array candidates correctly with M-sequence. We also confirm that we can suppress the flicker of the LED and improve the data rate as compared with the previous method.

  373. UWB Positioning Using Known Indoor Features - Environment Comparison Reviewed

    J. Kietlinski-Zaleski, T. Yamazato

    2010 International Conference on Indoor Positioning and Indoor Navigation (IPIN)     page: CD-ROM   2010.9

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    Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival (TOA) positioning, at least three receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In our previous work, we presented a novel 3D TOA UWB indoor positioning method that uses only two receivers. This is possible by exploiting the knowledge of some of the indoor features, namely ceiling and walls. In this work, we verify the usability of the method using measurement results in three environments: a lecture room, a cluttered laboratory and a corridor. By comparing the results of the method for three environments, we draw conclusions about its strengths and weaknesses.

  374. Fast Recognition of LED Array by High-Speed Camera Invited

    T. Yamazato

    Enginnering Sciences Society Conference of IEICE   Vol. AP-2   page: CD-ROM   2010.9

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  375. Implovement Method of transmission speed for Visible Light Communication System using LED Array and High-Speed Camera

    T. Ozawa, T. Nagura, T. Yamazato, T. Yendo, T. Fujii, H. Okada

    Enginnering Sciences Society Conference of IEICE   Vol. A-17-8   page: 154   2010.9

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  376. Channel Characteristics of Road-to-Vehicle Paralell Optical Communications Systems and Its Reciever

    K. Maeno, T. Yendo, T. Yamazato, H. Okada, M. P. Tehrani, T. Fujii, M. Tanimoto

    Forum on Informatio Technology   Vol. RM-003   page: CD-ROM   2010.9

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  377. LED Traffic Light Detection Using a High-speed-camera for a Road-to-vehicle Visible Light Communication System

    H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto

    Forum on Informatio Technology   Vol. RM-002   page: CD-ROM   2010.9

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  378. Study on parallel visible light communication using visually non-lighting LED

    K. Maeno, T. Yendo, M. P. Tehrani, T. Fujii, T. Yamazato, H. Okada, M. Tanimoto

    IEEJ General Conference,     page: CD-ROM   2010.8

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  379. A-17-8 Implovement Method of transmission speed for Visible Light Communication System using LED Array and High-Speed Camera Reviewed

    OZAWA Toshiyuki, NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    Proceedings of the Society Conference of IEICE   Vol. 2010   2010.8

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  380. AP-2-6 Fast Recognition of LED Array by High-Speed Camera Reviewed

    Yamazato Takaya

    Proceedings of the Society Conference of IEICE   Vol. 2010   page: "SS - 24"-"SS-25"   2010.8

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  381. Influence of quantization of brightness in road-vehicle communication

    K. Masuda, T. Yendo, T. Yamazato, H. Okada, P. Tehrani, T. Fujii, M. Tanimoto

    Toukai Shibu Rengou Taikai     page: -   2010.8

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  382. Inter-vehicle visible light communication using visually non-lighting LED

    K. Maeno, T. Yendo, M. P. Tehrani, T. Fujii, T. Yamazato, M. Tanimoto

    2010 IEE of Japan, Tokai Section, Wakate Seminar.     page: -   2010.8

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  383. Unique teaching practices presented at Nagoya Univeristy OCW

    T. Yamazato

    Japanese Society for Engineering Education 58th Annual Conference & Exposition   Vol. 10-107   page: -   2010.8

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  384. RM-002 LED Traffic Light Detection Using a High-speed-camera for a Road-to-vehicle Visible Light Communication System Reviewed

    Premachandra Halpage Chinthaka Nuwandika, Yendo Tomohiro, Tehrani Mehrdad Panahpour, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Tanimoto Masayuki

    情報科学技術フォーラム講演論文集   Vol. 9 ( 4 ) page: 45 - 50   2010.8

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    Publishing type:Research paper (scientific journal)   Publisher:FIT(電子情報通信学会・情報処理学会)運営委員会  

    A new visible light road-to-vehicle communication system at intersections is proposed for the area of ITS. In this system, the communication between a vehicle and an LED traffic light is conducted using an LED traffic light as a transmitter, and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light in high frequency and those emitting LEDs are captured by the high-speed camera for making communication. Here, the luminance value of LEDs in the transmitter should be captured in consecutive frames to achieve communication. For this purpose, finding the transmitter and tracking it in consecutive frames by processing the images from the high-speed camera is important. We propose new effective algorithms for finding and tracking the transmitter, which result in a increased communication speed, compared to the previous methods. Experiments using appropriate images showed the effectiveness of the proposals.

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  385. RM-003 Channel Characteristics and Receiving System of Road-vehicle Communication Reviewed

    MASUDA Takato, Yendo Tomohiro, YAMAZATO Takaya, OKADA Hiraku, TEHRANI Mehrdad Panahpour, FUJII Toshiaki, TANIMOTO Masayuki

      Vol. 9 ( 4 ) page: 51 - 55   2010.8

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  386. Experimental validation of TOA UWB positioning with two receivers using known indoor features Reviewed

    Kietlinski-Zaleski J.

    Record - IEEE PLANS, Position Location and Navigation Symposium     page: 505 - 509   2010.8

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    DOI: 10.1109/PLANS.2010.5507253

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  387. Performance evaluation of the cognitive piggyback overlay systems using QAM modulation

    J. Naganawa, K. Kobayashi, T. Yamazato, M. Katayama

    Technical Report of IEICE   Vol. SR2010-31   page: 89-94   2010.7

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  388. Improvement of the Sequential-Test-Based Cooperative Spectrum Sensing Systems in Band Limited Control Channels

    S. Mitsuya, K. Kobayashi, T. Yamazato, M. Katayama

    Technical Report of IEICE   Vol. SR2010-19   page: 19-24   2010.7

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    In a cooperative spectrum sensing system, many nodes perform spectrum sensing and report their decisions to one fusion center via control channels. This paper considers efficient use of the frequency band for the control channels. For this purpose, sequential-test is introduced for the local decision at each node. With this scheme, the transmission timing of the reports from nodes becomes at random and necessary maximum bandwidth for the control channels decreases. Numerical results show that this sequential-test-base-scheme not only decreases the number of simultaneous reports but also improves sensing reliability. For further improvement, this paper introduces a decision scheme at the fusion center based on probabilistic features of the reports from nodes.

  389. Visible Light Communication Between LED Array and On-vehicle High Speed Camera Reviewed

    H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto

    Technical Report of IEICE   Vol. ITS2010-10   page: 25-30   2010.7

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  390. Performance evaluation of the cognitive piggyback overlay systems using QAM modulation Reviewed

    NAGANAWA Jun, KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 110 ( 153 ) page: 89 - 94   2010.7

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    This manuscript considers a secondary system sharing the spectrum with the primary system at the same time and frequency. The proposed cognitive overlay system relays the primary signal and piggybacks its own data on it. As the modulation scheme, phase shift keying and quadrature amplitude modulation are considered and performance with them are compared. The result of the analysis for Rayleigh fading environment shows that the proposed scheme with regenerative relay allows the secondary signal to communicate at the same speed of the primary signal without any harm to it.

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  391. Improvement of the Sequential-Test-Based Cooperative Spectrum Sensing Systems in Band Limited Control Channels Reviewed

    MITSUYA Shohei, KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 110 ( 153 ) page: 19 - 24   2010.7

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In a cooperative spectrum sensing system, many nodes perform spectrum sensing and report their decisions to one fusion center via control channels. This paper considers efficient use of the frequency band for the control channels. For this purpose, sequential-test is introduced for the local decision at each node. With this scheme, the transmission timing of the reports from nodes becomes at random and necessary maximum bandwidth for the control channels decreases. Numerical results show that this sequential-test-base-scheme not only decreases the number of simultaneous reports but also improves sensing reliability. For further improvement, this paper introduces a decision scheme at the fusion center based on probabilistic features of the reports from nodes.

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  392. Visible Light Communication Between LED Array and On-vehicle High-speed Camera Reviewed

    Premachandra H. Chinthaka N., Yendo Tomohiro, Panahpour Tehrani Mehrdad, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, TANIMOTO Masayuki, Tanimoto Masayuki

    電子情報通信学会技術研究報告. ITS   Vol. 110 ( 150 ) page: 25 - 30   2010.7

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    We propose visible light road-to-vehicle communication system at intersections for ITS. In this system, the communication between a vehicle and an LED array is conducted using an LED array as a transmitter, and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light in high frequency and those emitting LEDs are captured by the high-speed camera for making communication. Here, the data is sent by emitting LEDs in the transmitter and those data is received by capturing luminance value of LEDs by high-speed camera. To achieve this, finding the transmitter and tracking it in consecutive frames is important. We propose new effective algorithms for finding and tracking the transmitter, which result in a increased communication speed, compared to the previous methods.

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  393. Effect of Slanted LED Traffic Light on Road-to-Vehicle Visible Light Communication Reviewed

    SHIRAKI Yasutake, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku, ARAI Shintaro

    IEICE technical report   Vol. 110 ( 150 ) page: 31 - 36   2010.7

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    In this paper, we discuss on road-to-vehicle visible light communications using an LED traffic light and a high-speed camera fixed to a vehicle. We assume that the camera is facing forwards and that it is parallel to the surface of the road. In our study, the LED traffic light in the image is slanted to represent the case in which the camera and the LED traffic light are not directly facing each other in an intersection. In order to demodulate data, we consider the slanting of the LED traffic light on the image. In this paper, we evaluate the effect the slanting of the LED traffic light on communication.

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  394. Study on parallel visible light communication using visually non-lighting LED Reviewed

    MAENO Keita, YENDO Tomohiro, PANAHPOUR TEHRANI Mehrdad, FUJII Toshiaki, YAMAZATO Takaya, OKADA Hiraku, TANIMOTO Masayuki

    IEICE technical report   Vol. 110 ( 150 ) page: 19 - 24   2010.7

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    Previous studies on visible light communication uses visually lighting LED. However, LEDs isn't always lighting. In this paper, we propose visible light communication method using visually non-lighting LED. This method enables us to communicate using visually non-lighting tail lamps of cars and visually non-lighting traffic lights and so on. We conduct two types of experiments to demonstrate the performance of the proposed system. The result shows possibility of communication using visually non-lighting LED.

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  395. Spectrum Efficiency Improvement by Dynamic Resource Allocation for Satellite Terrestrial Integrated Mobile Communication System Reviewed

    AMAN Tomohiro, YAMAZATO Takaya

    IEICE technical report   Vol. 110 ( 136 ) page: 97 - 102   2010.7

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    In Satellite Terrestrial Integrated Mobile Communication System, a single mobile terminal can communicate to both satellite and terrestrial communication systems depend upon his location, QoS and availability of resources among satellite and terrestrial communication systems. But it is hard to achieve high spectrum efficiency of Satellite Terrestrial Integrated Mobile Communication System using fixed resource allocation schemes because variation of satellite traffic and terrestrial traffic is different. In this paper, we propose dynamic resource allocation schemes according to traffic of satellite communication systems and terrestrial communication systems. Finally we show spectrum efficiency is improved by proposed scheme.

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  396. Spectrum Efficiency Improvement by Dynamic Resource Allocation for Satellite Terrestrial Integrated Mobile Communication System

    T. Aman, T. Yamazato

    Technical Report of IEICE   Vol. SAT2010-27   page: 97-102   2010.7

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    In Satellite Terrestrial Integrated Mobile Communication System, a single mobile terminal can com- municate to both satellite and terrestrial communication systems depend upon his location, QoS and availability of resources among satellite and terrestrial communication systems. But it is hard to achieve high spectrum efficiency of Satellite Terrestrial Integrated Mobile Communication System using fixed resource allocation schemes because variation of satellite traffic and terrestrial traffic is different. In this paper, we propose dynamic resource allocation schemes according to traffic of satellite communication systems and terrestrial communication systems. Finally we show spectrum efficiency is improved by proposed scheme.

  397. Effect of Slanted LED Traffic Light on Road-to-Vehicle Visible Light Communication

    Y. Shiraki, T. Yamazato, T. Yendo, T. Fujii, H. Okada, S. Arai

    Technical Report of IEICE   Vol. ITS2010-12   page: 31-36   2010.7

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    "In this paper, we discuss on road-to-vehicle visible light communications using an LED traffic light and a high-speed camera fixed to a vehicle. We assume that the camera is facing forwards and that it is parallel to the surface of the road.
    In our study, the LED traffic light in the image is slanted to represent the case in which the camera and the LED traffic light are not directly facing each other in an intersection. In order to demodulate data, we consider the slanting of the LED traffic light on the image. In this paper, we evaluate the effect the slanting of the LED traffic light on communication."

  398. Effects and Mitigation of Channel Errors in a Wireless Control System for Cooperative Motion of Machines Reviewed

    KONDO Tsugunori, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 110 ( 72 ) page: 57 - 62   2010.6

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    This manuscript discusses a wireless control system for cooperative motion of machines, and clarifies the influence of channel errors to a cooperative motion system. In addition, a new wireless control method is proposed to improve performance of cooperative motion when the channel errors occur. As an example of the controlled objects, rotary inverted pendulums with wireless connections in feedback loops are considered. In this study, we select a simple setting for cooperative motion, two rotary inverted pendulums are operated symmetrically. In order to improve the synchronization of their cooperative motion, we propose a system in which each pendulum receives control signals of it and also of the other pendulum. In addition, the main controller generates control signals for them based on the state information of both objects. The proposed system provides a better performance of cooperative motion than a conventional system with two independent feedback loops does.

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  399. Performance Evaluation of a Power Supply Overlaid Communication for Cooperative Motion of Multiple Machines Reviewed

    MINAMIYAMA Fumikazu, KOGA Hidetsugu, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 110 ( 72 ) page: 63 - 68   2010.6

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In order to reduce wiring in industrial machinery, we consider a cooperative-action system in which various devices (slaves) are multidrop-connected through a bus topology to a controlling master. Additionally, power is supplied together with communication signals over the same wiring. To accurately deliver timing information to the slaves, we propose the use of a spread spectrum (SS) signal. Together with the this signal, the control information signal is transmitted by applying an OFDM scheme. This manuscript provide an example of a set of system parameter to be used for an actual application. To assess the proposed method, the reception characteristics and mutual influence of the two overlaid signals is also explained.

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  400. High-speed-camera Image Processing Based LED Traffic Light Detection for Road-to-vehicle Visible Light Communication Reviewed

    H.C.N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto

    IEEE Intelligent Vehicles Symposium     page: 793-798   2010.6

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    As one of ITS technique, a new visible light road to- vehicle communication system at intersections is proposed. In this system, the communication between a vehicle and an LED traffic light is conducted using an LED traffic light as a transmitter, and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light in high frequency and those emitting LEDs are captured by the high-speed camera for making communication. Here, the luminance value of LEDs in the transmitter should be captured in consecutive frames to achieve effective communication. For this purpose, first the transmitter should be found, then it should be tracked in consecutive frames by processing the images from the high-speed camera. In this paper, we propose new effective algorithms for finding and tracking the transmitter, which result in a increased communication speed, compared to the previous methods. Experiments using appropriate images showed the effectiveness of the proposals.

  401. Effects and Mitigation of Channel Errors in a Wireless Control System for Cooperative Motion of Machines

    T. Kondo T. Yamazato M. Katayama

    Technical Report of IEICE   Vol. WBS2010-11   page: 57-62   2010.6

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    This manuscript discusses a wireless control system for cooperative motion of machines, and clarifies the influence of channel errors to a cooperative motion system. In addition, a new wireless control method is proposed to improve performance of cooperative motion when the channel errors occur. As an example of the controlled objects, rotary inverted pendulums with wireless connections in feedback loops are considered. In this study, we select a simple setting for cooperative motion, two rotary inverted pendulums are operated symmetrically. In order to improve the synchronization of their cooperative motion, we propose a system in which each pendulum receives control signals of it and also of the other pendulum. In addition, the main controller generates control signals for them based on the state information of both objects. The proposed system provides a better performance of cooperative motion than a conventional system with two independent feedback loops does.

  402. Performance evaluation of a power supply overlaid communication for cooperative motion of multiple machines.

    F.Minamiyama, H.Koga, T.Yamazato, M.Katayama

    Technical Report of IEICE   Vol. WBS2010-12   page: 63-68   2010.6

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    In order to reduce wiring in industrial machinery, we consider a cooperative-action system in which various devices (slaves) are multidrop-connected through a bus topology to a controlling master. Additionally, power is supplied together with communication signals over the same wiring. To accurately deliver timing information to the slaves, we propose the use of a spread spectrum(SS) signal. Together with the this signal, the control information signal is transmitted by applying an OFDM scheme. This manuscript provide an example of a set of system parameter to be used for an actual application. To assess the proposed method, the reception characteristics and mutual influence of the two overlaid signals is also explained.

  403. Extension of Network Lifetime Using Cooperative ARQ Protocol for Solar Energy Harvesting Wireless Sensor Networks Reviewed

    OTA Kentaro, KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 110 ( 50 ) page: 1 - 4   2010.5

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    Wireless sensor networks require long-term operation of sensor nodes and reliable data transmission. Attention is being focused on the use of environmental energy for battery charging as a long-term operation method for sensor nodes. Besides this, one of the reliable data transmission methods is cooperative ARQ (Automatic Repeat reQuest) protocol. In this paper, we apply a cooperative ARQ protocol to solar energy harvesting wireless sensor networks. By evaluating the cooperative ARQ protocol with network lifetime, we show that it is effective for extension of network lifetime.

    CiNii Article

  404. Joint Decoding Scheme Using Correlation of Observed Data According to ADC Bit Levels : Evaluation of Performance Improvement by Avoiding Carry Propagation of ADC Output Reviewed

    KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 110 ( 40 ) page: 69 - 74   2010.5

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    In wireless sensor networks, sensor nodes are densely deployed for reliable sensing of physical phenomenon. Due to the high density in the sensing field, sensor observations are spatially correlated. In this paper, we focus on a joint channel decoding scheme utilizing correlation of the sensor observations according to ADC bit levels. Our proposed scheme makes use of Gray code mapping to avoid carry propagation of sensor ADC outputs. The performance of our approach is examined by simulations using sensing data from experiments in a real indoor environment.

    CiNii Article

  405. Correlation Estimation for Joint Decoding of Correlated Observations According to ADC Bit Levels Reviewed

    KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    The IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Japanese edition) A   Vol. 93 ( 5 ) page: 353 - 364   2010.5

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  406. Correlation Estimation for Joint Decoding of Correlated Observations According to ADC Bit Levels Reviewed

    K. Kobayashi, T. Yamazato, M. Katayama

    IEICE Transactions on Fundamentals, vol.J93-A, no.5, pp.-, May 2010.   Vol. Vol.J93-A ( No.5 ) page: -   2010.5

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    In wireless sensor networks, a large number of sensor nodes are densely deployed for reliable environmental sensing. Due to the high density in the sensing field, sensor observations are spatially correlated. We focus on a property that such correlated observations are available in the form of ADC\\\'s binary output. In this paper, we study a joint decoding of transmitted data with correlation estimation according to ADC bit levels. Based on analysis of correlation estimation error, we propose a simple but effective estimation method. Our proposal achieves even when correlation of some bit levels have different amplitude and sign.

  407. Improved Decoding Methods of Visible Light Communication System for ITS using LED Array and High-Speed Camera Reviewed

    T. Nagura, T. Yamazato, M. Katayama, T. Yendo, T. Fujii, H. Okada

    IEEE Vehicular Technology Conference     page: -   2010.5

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    In this paper, we consider visible light communication systems using LED array as a transmitter and high-speed camera as a receiver for Intelligent Transport System (ITS). Previously, we have proposed the hierarchical coding scheme which allocates data to spatial frequency components of the image depending on the priority. This scheme is possible to receive information of the high-priority even if communication distance is long. However, we need to distinguish multi-valued data from the received image by using a hierarchical coding. In this paper, we propose two improved decoding methods, and demonstrate to distinguish multi-valued data more correctly in the experiment.

  408. Performance Evaluation of Error-Correcting Scheme Without Redundancy Code for Noncoherent Chaos Communications Reviewed

    S. Arai, Y. Nishio, T. Yamazato, S. Ozawa

    Proceedings of 2010 IEEE International Symposium on Circuits and Systems     page: -   2010.5

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    This paper considers a novel error-correcting scheme exploiting chaotic dynamics for noncoherent chaos communication. In our proposed system, two successive chaotic sequences are generated from the same chaotic map; the second sequence is generated with an initial value which is the last value of the first sequence. In this case, successive chaotic sequences having the same chaotic dynamics are created. This feature gives the receiver additional information to correctly recover the information data and thus improves the bit error performance of the receiver. Further, enhanced efficiency also comes from operating on successively modulated data; by involving less redundancy in the error correction system, it can be designed with high coding rate. In this paper, we analyze the scheme's capability, by examining computational times and accuracy rates of error correction. bounds on its capability.

  409. A-17-16 Sub-Pixel Estimation of LED Position for Visible Light Communication System using LED Array and High-Speed Camera Reviewed

    NAGURA Toru, YAMAZATO Takaya, KATAYAMA Masaaki, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    Proceedings of the IEICE General Conference   Vol. 2010   2010.3

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    CiNii Article

  410. A-4-3 BER Property of Visible Light Communication System Using LED Array and High-Speed Camera Reviewed

    SHIRAKI Yasutake, YAMAZATO Takaya, KATAYAMA Masaaki, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    Proceedings of the IEICE General Conference   Vol. 2010   2010.3

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  411. B-17-15 A Weight Combination Scheme for Sequential-Test-Based Cooperative Spectrum Sensing Systems Reviewed

    Mitsuya Shohei, Yamazato Takaya, Katayama Masaaki

    Proceedings of the IEICE General Conference   Vol. 2010 ( 1 )   2010.3

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    CiNii Article

  412. B-3-33 Improvement of Spectrum Efficiency by Dynamic Resource Allocation for Satellite Terrestrial Integrated Mobile Communication System Reviewed

    AMAN Tomohiro, YAMAZATO Takaya, KATAYAMA Masaaki

    Proceedings of the IEICE General Conference   Vol. 2010 ( 1 )   2010.3

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  413. An Access Control Method for Multipoint Cyclic Data Gathering over a PLC Network Reviewed

    Y. Ohtomo, T. Yamazato, M. Katayama

    IEEE International Symposium on Power Line Communications and Its Applications     page: -   2010.3

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    This paper proposes a media access control method for a multipoint cyclic data gathering system, in which each node transmits its data to the base-station periodically. In such condition, by broadcasting ACK/NACK signals from the base-station, the proposed method ensures assignment of a time slot for each node once the node succeeds to transfer its data. It is confirmed that the proposed scheme reduces packet collisions and outperforms conventional slotted-ALOHA scheme in throughput of data even with ACK/NACK errors. Furthermore the proposed scheme realizes adaptive slot assignment under cyclostationary channel environment.

  414. BER Property of Visible Light Communication System Using LED Array and High-Speed Camera

    Y. Shiraki, T. Yamazato, M. Katayama, T. Yendo, T. Fujii, H. Okada

    IEICE General Conference     page: -   2010.3

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  415. A Weight Combination Scheme for Sequential-Test-Based Cooperative Spectrum Sensing Systems

    M.Mitsuya, T. Yamazato, M. Katayama

    IEICE General Conference     page: -   2010.3

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  416. Sub-pixel Estimation of LED Position for Visible Light Communication System using LED Array and High-Speed Camera

    T. Nagura, T. Yamazato, M. Katayama, T. Yendo, T. Fujii, H. Okada

    IEICE General Conference     page: -   2010.3

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  417. Introduction of dirty paper coding for the cognitive piggyback overlay systems

    J. Naganawa, T. Yamazato, M. Katayama

    IEICE General Conference     page: -   2010.3

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  418. Wireless Control Scheme with Noisy Channels for Cooperative Motion Systems

    T. Kondo, T. Yamazato, M. Katayama

    IEICE General Conference     page: -   2010.3

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  419. Kalman Channel Estimator for MC-CDMA based Inter-Vehicle Communication

    N. Hiraiwa, T. Yamazato, M. Katayama

    Technical Report of IEICE     page: -   2010.3

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    In this paper, we propose a kalman channel estimator for MC-CDMA based Inter-Vehicle Communication(IVC). In IVC, the channel characteristic of each car is different among pilot signals because of a doppler shift, a multipath fading, and the difference of receiving power. Our proposed kalman channel estimator uses a kalman filter to track the channel fluctuation and implements a pilot-based channel estimation which interpolates among pilot signals by using an interpolation polynomial into our proposed channel estimator to suppress an estimation error. As results, we show that the kalman channel estimator shows better performance than a pilot-based channel estimation.

  420. Successive Interference Cancellation for Hierarchical Coding in Optical Wireless Communication Systems using LED array and High speed camera Reviewed

    OZAWA Toshiyuki, NAGURA Toru, YAMAZATO Takaya, KATAYAMA Masaaki, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report   Vol. 109 ( 415 ) page: 53 - 58   2010.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We propose a successive interference cancellation scheme (SIC) for the hierarchical coding parallel optical communication system using LED array and high-speed camera. The high priority data is first demodulated and Turbo-decoded. The retrieved high priority data is then re-modulated and subtracted from the received signal. In this way, the reliability of the middle priority data can be improved as the interference caused by the high priority data can be reduced. By the way, the performance of SIC depends on the performance of Turbo code. In this paper, we apply LogMAP decoding to improve the performance instead of MaxLogMAP algorithm that we have used in the previous.

    CiNii Article

  421. Kalman Channel Estimator for MC-CDMA based Inter-Vehicle Communication Reviewed

    HIRAIWA Noriaki, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 415 ) page: 47 - 52   2010.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we propose a kalman channel estimator for MC-CDMA based Inter-Vehicle Communication (IVC). In IVC, the channel characteristic of each car is different among pilot signals because of a doppler shift, a multipath fading, and the difference of receiving power. Our proposed kalman channel estimator uses a kalman filter to track the channel fluctuation and implements a pilot-based channel estimation which interpolates among pilot signals by using an interpolation polynomial into our proposed channel estimator to suppress an estimation error. As results, we show that the kalman channel estimator shows better performance than a pilot-based channel estimation.

    CiNii Article

  422. Kalman Channel Estimator for MC-CDMA based Inter-Vehicle Communication Reviewed

    HIRAIWA Noriaki, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 414 ) page: 47 - 52   2010.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we propose a kalman channel estimator for MC-CDMA based Inter-Vehicle Communication(IVC). In IVC, the channel characteristic of each car is different among pilot signals because of a doppler shift, a multipath fading, and the difference of receiving power. Our proposed kalman channel estimator uses a kalman filter to track the channel fluctuation and implements a pilot-based channel estimation which interpolates among pilot signals by using an interpolation polynomial into our proposed channel estimator to suppress an estimation error. As results, we show that the kalman channel estimator shows better performance than a pilot-based channel estimation.

    CiNii Article

  423. Successive Interference Cancellation for Hierarchical Coding in Optical Wireless Communication Systems using LED array and High speed camera Reviewed

    OZAWA Toshiyuki, NAGURA Toru, YAMAZATO Takaya, KATAYAMA Masaaki, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report   Vol. 109 ( 414 ) page: 53 - 58   2010.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We propose a successive interference cancellation scheme(SIC)for the hierarchical coding parallel optical communication system using LED array and high-speed camera. The high priority data is first demodulated and Turbo-decoded. The retrieved high priority data is then re-modulated and subtracted from the received signal. In this way, the reliability of the middle priority data can be improved as the interference caused by the high priority data can be reduced. By the way, the performance of SIC depends on the performance of Turbo code. In this paper, we apply LogMAP decoding to improve the performance instead of MaxLogMAP algorithm that we have used in the previous.

    CiNii Article

  424. Detection and Tracking of LED Array Transmitter for Visible Light Communications on Driving Situation Reviewed

    NAGURA Toru, OZAWA Toshiyuki, YAMAZATO Takaya, KATAYAMA Masaaki, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report   Vol. 109 ( 414 ) page: 59 - 64   2010.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we discuss on a decoding algorithm for visible light communication systems on driving situation using a LED array transmitter and a high-speed camera receiver. We propose a LED array detection method using M-sequence and a LED array tracking method using inversion signals. We demonstrate that we can distinguish LED array candidates correctly with M-sequence. We also demonstrate that we can suppress the flicker of LED and improve the data rate compared with the conventional method.

    CiNii Article

  425. Detection and Tracking of LED Array Transmitter for Visible Light Communications on Driving Situation Reviewed

    NAGURA Toru, OZAWA Toshiyuki, YAMAZATO Takaya, KATAYAMA Masaaki, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    IEICE technical report   Vol. 109 ( 415 ) page: 59 - 64   2010.2

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper, we discuss on a decoding algorithm for visible light communication systems on driving situation using a LED array transmitter and a high-speed camera receiver. We propose a LED array detection method using M-sequence and a LED array tracking method using inversion signals. We demonstrate that we can distinguish LED array candidates correctly with M-sequence. We also demonstrate that we can suppress the flicker of LED and improve the data rate compared with the conventional method.

    CiNii Article

  426. Detection and Tracking of LED Array Transmitter for Visible Light Communications on Driving Situation

    T. Nagura, T. Ozawa, T. Yamazato, M. Katayama, T. Yendo, T. Fujii, H. Okada

    Technical Report of IEICE     page: -   2010.2

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    In this paper, we discuss on a decoding algorithm for visible light communication systems on driving situation using a LED array transmitter and a high-speed camera receiver. We propose a LED array detection method using M-sequence and a LED array tracking method using inversion signals. We demonstrate that we can distinguish LED array candidates correctly with M-sequence. We also demonstrate that we can suppress the flicker of LED and improve the data rate compared with the conventional method.

  427. An application of regenerative relay to the cognitive piggyback overlay system

    J.Naganawa, T.Yamazato, M.Katayama

    Technical Report of IEICE, vol.109, no.383 (SR2009-75), pp.9-14   Vol. Vol.109 ( No.383 (SR2009-75) ) page: pp.9-14,   2010.2

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    This manuscript considers a secondary system sharing the spectrum with the primary system at the same time and same frequency. This manuscript proposes a cognitive overlay system, in which the secondary system relays the primary signal and piggybacks its own data on it. As the relay procedure, non-regenerative and regenerative repeaters are considered and performance with them are compared. The result of the analysis shows that the proposed scheme with regenerative relay allows the secondary signal to communicate at the same speed of the primary signal without any harm to it.

  428. Successive Interference Cancellation for Hierarchical Coding in Optical Wireless Communication Systems using LED array and High speed camera

    T.Ozawa, T.Nagura, T.Yamazato, M.Katayama, T.Yendo T.Fujii, H.Okada

    Technical Report of IEICE     page: -   2010.2

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    Language:Japanese  

    We propose a successive interference cancellation scheme (SIC) for the hierarchical coding parallel optical communicationsystem using LED array and high-speed camera. The high priority data is first demodulated and Turbo-decoded. The retrieved high priority data is then re-modulated and subtracted from the received signal. In this way, the reliability of the middle priority data can be improved as the interference caused by the high priority data can be reduced. By the way, the performance of SIC depends on the performance of Turbo code. In this paper, we apply LogMAP decoding to improve the performance instead of MaxLogMAP algorithm that we have used in the previous.

  429. An Access Control Method for Multipoint Data Gathering with ACK/NACK Errors Reviewed

    OHTOMO Yuzo, YAMAZATO Takaya, KATAYAMA Masaaki

      Vol. 2010 ( 1 ) page: 21 - 26   2010.1

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    CiNii Article

  430. An application of regenerative relay to the cognitive piggyback overlay system Reviewed

    NAGANAWA Jun, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 383 ) page: 9 - 14   2010.1

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This manuscript considers a secondary system sharing the spectrum with the primary system at the same time and same frequency. This manuscript proposes a cognitive overlay system, in which the secondary system relays the primary signal and piggybacks its own data on it. As the relay procedure, non-regenerative and regenerative repeaters are considered and performance with them are compared. The result of the analysis shows that the proposed scheme with regenerative relay allows the secondary signal to communicate at the same speed of the primary signal without any harm to it.

    CiNii Article

  431. An access control method for multipoint data gathering with ACK/NACK errors

    Y. Ohtomo, T. Yamazato, M. Katayama

    The Papers of Technical Meeting on Communications, IEE Japan, pp21-26     page: pp21-26   2010.1

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    This manuscript proposes a media access control method for a multipoint cyclic data gathering system, in witch a base-station collects data generated periodically at each node. In such condition, by broadcasting ACK/NACK signals form the base-station, the proposed method ensures assignment a time slot for each node once the node succeeds to transfer its data. It is confirmed that the proposed method outperforms conventional slotted-ALOHA in throughput of data even with ACK/NACK errors. Furthermore, the proposed method realizes adaptive slot assignment under cyclostationary channel environment.

  432. Nagoya Univeristy OCW

    Takaya YAMAZATO

    Japanese Society for Engineering Education 57th Annual Conference     page: -   2010.1

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  433. 10-107 Unique teaching practices presented at Nagoya Univeristy OCW Reviewed

    Yamazato Takaya

    Proceedings of Annual Conference of Japanese Society for Engineering Education   Vol. 2010 ( 0 ) page: 210 - 211   2010

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    Publishing type:Research paper (scientific journal)   Publisher:Japanese Society for Engineering Education  

    DOI: 10.20549/jseejaarc.2010.0_210

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  434. 1-5 Study on parallel visible light communication using visually non-lighting LED Reviewed

    MAENO Keita, YENDO Tomohiro, PANAHPOUR TEHRANI Mehrdad, FUJII Toshiaki, YAMAZATO Takaya, OKADA Hiraku, TANIMOTO Masayuki

    PROCEEDINGS OF THE ITE ANNUAL CONVENTION   Vol. 2010 ( 0 ) page: 1 - 5-1-_1-5-2_   2010

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    The proposed visible light communication method uses visually non-lighting LED, which enable us to communicate by using tail lamps of cars. In addition, this method can communicate with visually non-lighting traffic lights.

    DOI: 10.11485/iteac.2010.0_1-5-1

    CiNii Article

  435. A study on joint channel decoding using spatial correlation of sensor observations according to ADC bit levels Reviewed

    Kentaro Kobayashi, Takaya Yamazato, Masaaki Katayama

    IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC     page: 485 - 490   2010

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    In densely deployed wireless sensor networks, observations of the sensor nodes are spatially correlated. In this paper, we study a joint channel decoding scheme utilizing bit correlation of the sensor observations according to bit levels of analog-digital converter (ADC). If sensor ADC output is interpreted as natural binary numeral, carry propagation may occur between adjacent ADC output values. Such carry propagation leads to the degradation of joint decoding gain. We focus on the use of Gray code for avoiding the carry propagation. The performance of our approach is demonstrated by simulations using sensor data from experiments in a real indoor environment. ©2010 IEEE.

    DOI: 10.1109/PIMRCW.2010.5670522

    Scopus

  436. An access control method for multipoint cyclic data gathering over a PLC network Reviewed

    Yuzo Ohtomo, Takaya Yamazato, Masaaki Katayama

    IEEE ISPLC 2010 - International Symposium on Power Line Communications and its Applications     page: 285 - 290   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)  

    This paper proposes a media access control method for a multipoint cyclic data gathering system, in which each node transmits its data to the base-station periodically. In such condition, by broadcasting ACK/NACK signals from the basestation, the proposed method ensures assignment of a time slot for each node once the node succeeds to transfer its data. It is confirmed that the proposed scheme reduces packet collisions and outperforms conventional slotted-ALOHA scheme in throughput of data even with ACK/NACK errors. Furthermore the proposed scheme realizes adaptive slot assignment under cyclostationary channel environment. ©2010 IEEE.

    DOI: 10.1109/ISPLC.2010.5479914

    Scopus

  437. Dynamic Bandwidth Allocation of Satellite/Terrestrial Integrated Mobile Communication System Reviewed

    Yamazato Takaya, Aman Tomohiro, Katayama Masaaki

    2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010     2010

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    Web of Science

  438. Error-correcting scheme based on chaotic dynamics and its performance for noncoherent chaos communications Reviewed

    Arai Shintaro, Nishio Yoshifumi, Yamazato Takaya

    Nonlinear Theory and Its Applications, IEICE   Vol. 1 ( 1 ) page: 196 - 206   2010

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    Publishing type:Research paper (scientific journal)   Publisher:一般社団法人 電子情報通信学会  

    This paper proposes a novel error-correcting scheme using chaotic dynamics for noncoherent chaos communications. In our proposed system, two successive chaotic sequences are generated from the same chaotic map; the second sequence is generated with an initial value which is the last value of the first sequence. In this case, successive chaotic sequences having the same chaotic dynamics are created. This feature gives the receiver additional information to correctly recover the information data and thus improves the bit error performance of the receiver. As results of the computer simulation, we confirm that the advantage gained in BER performance of the proposed error-correcting method is about 1-1.5 dB compared to conventional method. In addition, we achieve that the proposed error-correcting scheme is performed without the new additional redundancy code by using the chaotic dynamics.<br/>

    DOI: 10.1587/nolta.1.196

    CiNii Article

  439. Dynamic Bandwidth Allocation of Satellite/Terrestrial Integrated Mobile Communication System Reviewed

    Takaya Yamazato, Tomohiro Aman, Masaaki Katayama

    2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010     page: 1 - 5   2010

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    In this paper, we propose two dynamic bandwidth allocation (DBA) schemes, a game theory based DBA and a successive DBA, for satellite/terrestrial integrated mobile communication system (STICS). The game theory based DBA allocate the bandwidth according to a utility function based on a weighted demand bandwidth of both satellite and terrestrial system. The successive DBA recursively allocates an unit of bandwidth according to a weighted number of bandwidth unfilled cells of both satellite and terrestrial systems, until the total bandwidth is fulfilled. As results, both DBA outperform the conventional fixed bandwidth allocation scheme. Between two proposed DBA, the successive DBA shows better spectral improvement ratio than the game theory based DBA.

    DOI: 10.1109/GLOCOM.2010.5683362

    Web of Science

    Scopus

  440. Experimental Validation of TOA UWB Positioning with Two Receivers Using Known Indoor Features Reviewed

    Kietlinski-Zaleski Jan, Yamazato Takaya, Katayama Masaaki

    2010 IEEE-ION POSITION LOCATION AND NAVIGATION SYMPOSIUM PLANS     page: 748 - 752   2010

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    Web of Science

  441. Inband and outband spectrum analysis of the BFDM and BFDM/OQAM signals with truncated Gaussian pulses Reviewed

    Bayarpurev Mongol, Takaya Yamazato, Masaaki Katayama

    ISITA/ISSSTA 2010 - 2010 International Symposium on Information Theory and Its Applications     page: 743 - 746   2010

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    Pulse-shaping OFDM, or more generally BFDM and BFDM/OQAM, systems are originally proposed to combat inter-carrier interference (ICI) caused by time-variance of the channel. The main property that makes these signals robust against ICI is that they allow to employ time-frequency well localized pulses, particularly Gaussian pulse which has the best time-frequency localization. However, this property also suppresses the outband or inband spectral leakage of the BFDM and BFDM/OQAM signal, making them attractive physical layer modulation scheme for cognitive radio. In this paper we analyze the power density spectra of the BFDM and BFDM/OQAM signals and numerically evaluate the inband and outband spectra for truncated Gaussian pulses. © 2010 IEEE.

    DOI: 10.1109/ISITA.2010.5649641

    Scopus

  442. Improvement of sequential-test-based cooperative spectrum sensing systems in band limited control channels Reviewed

    Shohei Mitsuya, Kentaro Kobayashi, Takaya Yamazato, Masaaki Katayama

    ISCIT 2010 - 2010 10th International Symposium on Communications and Information Technologies     page: 968 - 973   2010

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    In a cooperative spectrum sensing system, many nodes perform spectrum sensing and report their decisions to one fusion center via control channels. This paper considers efficient use of the frequency band for the control channels. For this purpose, sequential-test is introduced for the local decision at each node. With this scheme, the transmission timing of the reports from the nodes becomes at random and necessary maximum bandwidth for the control channels decreases. Numerical results show that this sequential-test-base-scheme not only decreases the number of simultaneous reports but also improves sensing reliability. For further improvement, this paper also introduces a decision scheme at the fusion center based on probabilistic features of the reports from the nodes. ©2010 IEEE.

    DOI: 10.1109/ISCIT.2010.5665127

    Scopus

  443. Improved Decoding Methods of Visible Light Communication System for ITS using LED Array and High-Speed Camera Reviewed

    Toru Nagura, Takaya Yamazato, Masaaki Katayama, Tomohiro Yendo, Toshiaki Fujii, Hiraku Okada

    2010 IEEE 71ST VEHICULAR TECHNOLOGY CONFERENCE     page: 1 - 5   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    In this paper, we consider visible light communication system using LED array as a transmitter and high-speed camera as a receiver for Intelligent Transport System (ITS). Previously, we have proposed the hierarchical coding scheme which allocates data to spatial frequency components of the image depending on the priority. This scheme is possible to receive information of the high-priority even if communication distance is long. However, we need to distinguish multi-valued data from the received image by using a hierarchical coding. In this paper, we propose two improved decoding methods, and demonstrate to distinguish multi-valued data more correctly in the experiment.

    DOI: 10.1109/VETECS.2010.5493958

    Web of Science

    Scopus

  444. Improved Decoding Methods of Visible Light Communication System for ITS using LED Array and High-Speed Camera Reviewed

    Nagura Toru, Yamazato Takaya, Katayama Masaaki, Yendo Tomohiro, Fujii Toshiaki, Okada Hiraku

    2010 IEEE 71ST VEHICULAR TECHNOLOGY CONFERENCE     2010

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    Web of Science

  445. High-speed-camera Image Processing Based LED Traffic Light Detection for Road-to-vehicle Visible Light Communication Reviewed

    H. Chinthaka N. Premachandra, Tomohiro Yendo, Mehrdad Panahpour Tehrani, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Masayuki Tanimoto

    2010 IEEE INTELLIGENT VEHICLES SYMPOSIUM (IV)     page: 793 - 798   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    As one of ITS technique, a new visible light road-to-vehicle communication system at intersections is proposed. In this system, the communication between a vehicle and an LED traffic light is conducted using an LED traffic light as a transmitter, and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light in high frequency and those emitting LEDs are captured by the high-speed camera for making communication. Here, the luminance value of LEDs in the transmitter should be captured in consecutive frames to achieve effective communication. For this purpose, first the transmitter should be found, then it should be tracked in consecutive frames by processing the images from the high-speed camera. In this paper, we propose new effective algorithms for finding and tracking the transmitter, which result in a increased communication speed, compared to the previous methods. Experiments using appropriate images showed the effectiveness of the proposals.

    DOI: 10.1109/IVS.2010.5548097

    Web of Science

    Scopus

  446. High-speed-camera Image Processing Based LED Traffic Light Detection for Road-to-vehicle Visible Light Communication Reviewed

    Premachandra H. Chinthaka N., Yendo Tomohiro, Tehrani Mehrdad Panahpour, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Tanimoto Masayuki

    2010 IEEE INTELLIGENT VEHICLES SYMPOSIUM (IV)     page: 793 - 798   2010

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    Web of Science

  447. Experimental Validation of TOA UWB Positioning with Two Receivers Using Known Indoor Features Reviewed

    Jan Kietlinski-Zaleski, Takaya Yamazato, Masaaki Katayama

    2010 IEEE-ION POSITION LOCATION AND NAVIGATION SYMPOSIUM PLANS     page: 748 - 752   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival (ToA) positioning, at least three receivers with unblocked direct path to the transmitter are required. This requirement is not always met. In this work, a novel algorithm for ToA positioning using only two receivers is presented and validated using data from a measurement campaign. Positioning with two receivers is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, for example ceiling and walls.

    Web of Science

  448. Successive Interference Cancellation for Hierarchical Coding in Optical Wireless Communication Systems using LED array and High speed camera Reviewed

    OZAWA Toshiyuki, NAGURA Toru, YAMAZATO Takaya, KATAYAMA Masaaki, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    ITE Technical Report   Vol. 34 ( 0 ) page: 53 - 58   2010

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    We propose a successive interference cancellation scheme (SIC)for the hierarchical coding parallel optical communication system using LED array and high-speed camera. The high priority data is first demodulated and Turbo-decoded. The retrieved high priority data is then re-modulated and subtracted from the received signal. In this way, the reliability of the middle priority data can be improved as the interference caused by the high priority data can be reduced. By the way, the performance of SIC depends on the performance of Turbo code. In this paper, we apply LogMAP decoding to improve the performance instead of MaxLogMAP algorithm that we have used in the previous.

    DOI: 10.11485/itetr.34.6.0_53

    CiNii Article

  449. Kalman Channel Estimator for MC-CDMA based Inter-Vehicle Communication Reviewed

    HIRAIWA Noriaki, YAMAZATO Takaya, KATAYAMA Masaaki

    ITE Technical Report   Vol. 34 ( 0 ) page: 47 - 52   2010

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    In this paper, we propose a kalman channel estimator for MC-CDMA based Inter-Vehicle Communication (IVC). In IVC, the channel characteristic of each car is different among pilot signals because of a doppler shift, a multipath fading, and the difference of receiving power. Our proposed kalman channel estimator uses a kalman filter to track the channel fluctuation and implements a pilot-based channel estimation which interpolates among pilot signals by using an/interpolation polynomial into our proposed channel estimator to suppress an estimation error. As results, we show that the kalman channel estimator shows better performance than a pilot-based channel estimation.

    DOI: 10.11485/itetr.34.6.0_47

    CiNii Article

  450. Optimal cluster partitioning for wireless sensor networks with cooperative MISO scheme Reviewed

    Zheng Huang, Takaya Yamazato, Masaaki Katayama

    6th Advanced International Conference on Telecommunications, AICT 2010     page: 323 - 328   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE Computer Society  

    The paper discusses the optimal cluster partitioning for wireless sensor networks deployed in continuous areas. Both single-hop and multi-hop transmissions with cooperative Multi-Input Single-Output (MISO) scheme are considered for inter-cluster communications. The effects of cluster size in the energy consumption of intra-cluster communication and the amount of fused data are included in calculation. As a result, the dominant factors of the maximal network lifetimes are listed as: the cluster farthest from base station in single-hop transmission and the closest cluster in multi-hop transmission. In addition, the maximal network lifetimes of single-hop and multi-hop transmissions are compared and it is found that there exists a threshold of network size that determines which transmission is the better candidate. © 2010 IEEE.

    DOI: 10.1109/AICT.2010.67

    Scopus

  451. Performance evaluation of the cognitive piggyback overlay systems with dirty paper coding Reviewed

    Jun Naganawa, Kentaro Kobayashi, Masaaki Katayama, Takaya Yamazato

    ISCIT 2010 - 2010 10th International Symposium on Communications and Information Technologies     page: 974 - 979   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)  

    This manuscript considers a secondary system sharing the spectrum with the primary system at the same time and on the same frequency. We propose a cognitive overlay system in which the secondary system relays the primary signal and piggybacks its own data on it. Furthermore, the secondary system uses the channel coding based on the dirty paper coding (DPC). The result of the analysis shows that the proposed scheme allows the secondary system to communicate at the same speed as the primary system without any harm to it. ©2010 IEEE.

    DOI: 10.1109/ISCIT.2010.5665130

    Scopus

  452. Performance Evaluation of Error-Correcting Scheme Without Redundancy Code for Noncoherent Chaos Communications Reviewed

    Shintaro Arai, Yoshifumi Nishio, Takaya Yamazato, Shinji Ozawa

    2010 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS     page: 2458 - 2461   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This paper considers a novel error-correcting scheme exploiting chaotic dynamics for noncoherent chaos communication. In our proposed system, two successive chaotic sequences are generated from the same chaotic map; the second sequence is generated with an initial value which is the last value of the first sequence. In this case, successive chaotic sequences having the same chaotic dynamics are created. This feature gives the receiver additional information to correctly recover the information data and thus improves the bit error performance of the receiver. Further, enhanced efficiency also comes from operating on successively modulated data; by involving less redundancy in the error correction system, it can be designed with high coding rate. In this paper, we analyze the scheme's capability, by examining computational times and accuracy rates of error correction. bounds on its capability.

    DOI: 10.1109/ISCAS.2010.5537140

    Web of Science

    Scopus

  453. Performance Evaluation of Error-Correcting Scheme Without Redundancy Code for Noncoherent Chaos Communications Reviewed

    Arai Shintaro, Nishio Yoshifumi, Yamazato Takaya, Ozawa Shinji

    2010 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS     page: 2458 - 2461   2010

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  454. Tracking an LED array transmitter for visible light communications in the driving situation Reviewed

    Toru Nagura, Takaya Yamazato, Masaaki Katayama, Tomohiro Yendo, Toshiaki Fujii, Hiraku Okada

    Proceedings of the 2010 7th International Symposium on Wireless Communication Systems, ISWCS'10     page: 765 - 769   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    In this paper, we discuss on a decoding algorithm for visible light communication systems in the driving situation using an LED array transmitter and a high-speed camera receiver. We propose an LED array detection method using M-sequence and an LED array tracking method using inverted signals. We confirm that we can distinguish LED array candidates correctly with M-sequence. We also confirm that we can suppress the flicker of the LED and improve the data rate as compared with the previous method. © 2010 IEEE.

    DOI: 10.1109/ISWCS.2010.5624361

    Scopus

  455. B-17-3 Introduction of dirty paper coding for the cognitive piggyback overlay systems Reviewed

    Naganawa Jun, Yamazato Takaya, Katayama Masaaki

    Proceedings of the IEICE General Conference     2010

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  456. お熱いのがお好き Reviewed

    山里 敬也

    電子情報通信学会 通信ソサイエティマガジン   Vol. 2010 ( 15 ) page: 15_79 - 15_79   2010

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    Publishing type:Research paper (scientific journal)   Publisher:一般社団法人 電子情報通信学会  

    DOI: 10.1587/bplus.2010.15_79

    CiNii Article

  457. UWB Positioning Using Known Indoor Features - Environment Comparison Reviewed

    Jan Kietlinski-Zaleski, Takaya Yamazato

    2010 INTERNATIONAL CONFERENCE ON INDOOR POSITIONING AND INDOOR NAVIGATION     2010

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival (TOA) positioning, at least three receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In our previous work [1] we presented a novel 3D TOA UWB indoor positioning method that uses only two receivers. This is possible by exploiting the knowledge of some of the indoor features, namely ceiling and walls. In this work, we verify the usability of the method using measurement results in three environments: a lecture room, a cluttered laboratory and a corridor. By comparing the results of the method for three environments, we draw conclusions about its strengths and weaknesses.

    Web of Science

  458. UWB Positioning Using Known Indoor Features - Environment Comparison Reviewed

    Kietlinski-Zaleski Jan, Yamazato Takaya

    2010 INTERNATIONAL CONFERENCE ON INDOOR POSITIONING AND INDOOR NAVIGATION     2010

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    Web of Science

  459. A-5-17 Wireless Control Scheme with Noisy Channels for Cooperative Motion Systems Reviewed

    KONDO Tsugunori, YAMAZATO Takaya, KATAYAMA Masaaki

    Proceedings of the IEICE General Conference   Vol. 119   2010

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

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  460. Detection and Tracking of LED Array Transmitter for Visible Light Communications on Driving Situation Reviewed

    NAGURA Toru, OZAWA Toshiyuki, YAMAZATO Takaya, KATAYAMA Masaaki, YENDO Tomohiro, FUJII Toshiaki, OKADA Hiraku

    ITE Technical Report   Vol. 34 ( 0 ) page: 59 - 64   2010

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    In this paper, we discuss on a decoding algorithm for visible light communication systems on driving situation using a LED array transmitter and a high-speed camera receiver. We propose a LED array detection method using M-sequence and a LED array tracking method using inversion signals. We demonstrate that we can distinguish LED array candidates correctly with M-sequence. We also demonstrate that we can suppress the flicker of LED and improve the data rate compared with the conventional method.

    DOI: 10.11485/itetr.34.6.0_59

    CiNii Article

  461. TOA UWB position estimation with two receivers and a set of known reflectors Reviewed

    Kietlinski-Zaleski J.

    Proceedings - 2009 IEEE International Conference on Ultra-Wideband, ICUWB 2009     page: 376 - 380   2009.12

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    Publishing type:Research paper (scientific journal)   Publisher:Proceedings - 2009 IEEE International Conference on Ultra-Wideband, ICUWB 2009  

    DOI: 10.1109/ICUWB.2009.5288686

    Scopus

  462. Traffic prediction scheme for resource assignment of satellite/terrestrial frequency sharing mobile communication system Reviewed

    Aman T.

    IWSSC'09 - 2009 International Workshop on Satellite and Space Communications - Conference Proceedings     page: 40 - 44   2009.12

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    Publishing type:Research paper (scientific journal)   Publisher:IWSSC'09 - 2009 International Workshop on Satellite and Space Communications - Conference Proceedings  

    DOI: 10.1109/IWSSC.2009.5286430

    Scopus

  463. On-Vehicle Receiver for Road-to-Vehicle Communication System Reviewed

    OKADA Satoshi, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, TEHRANI Mehrdad Panahpour, FUJII Toshiaki, TANIMOTO Masayuki

    IEICE technical report   Vol. 109 ( 323 ) page: 77 - 82   2009.11

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We consider an on-vehicle receiving system for long-distance and high-speed visible light communication. There are several problems associated with applying visible light communication to the field of ITS. It is necessary to receive information from long distance. And tracking the transmitter for a certain moving distance of the vehicle is also important. We applied an imaging optics to receive information over long distance, and two cameras are used to solve the relationship between the transmitter and the receiver position changes with time, and vibrational correction technique is also fixed to the system to minimize vibrational affections.

    CiNii Article

  464. On-Vehicle Receiver for Road-to-Vehicle Communication System Reviewed

    OKADA Satoshi, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, PANAHPOUR TEHRANI Mehrdad, FUJII Toshiaki, TANIMOTO Masayuki

    IEICE technical report   Vol. 109 ( 322 ) page: 77 - 81   2009.11

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    We consider an on-vehicle receiving system for long-distance and high-speed visible light communication. There are several problems associated with applying visible light communication to the field of ITS. It is necessary to receive information from long distance. And tracking the transmitter for a certain moving distance of the vehicle is also important. We applied an imaging optics to receive information over long distance, and two cameras are used to solve the relationship between the transmitter and the receiver position changes with time, and vibrational correction technique is also fixed to the system to minimize vibrational affections.

    CiNii Article

  465. On-vehicle receiver for distant visible light road-to-vehicle communication Reviewed

    Okada S.

    IEEE Intelligent Vehicles Symposium, Proceedings     page: 1033 - 1038   2009.11

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    Publishing type:Research paper (scientific journal)   Publisher:IEEE Intelligent Vehicles Symposium, Proceedings  

    DOI: 10.1109/IVS.2009.5164423

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  466. Channel estimation and tracking schemes for the pulse-shaping OFDM systems Reviewed

    Mongol B.

    IEEE International Conference on Communications     2009.11

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    Publishing type:Research paper (scientific journal)   Publisher:IEEE International Conference on Communications  

    DOI: 10.1109/ICC.2009.5198817

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  467. Encoding system based on spatial frequency characteristics of road-vehicle communication Reviewed

    MASUDA Takato, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, TEHRANI Mehrdad Panahpour, FUJII Toshiaki, TANIMOTO Masayuki

    IEICE technical report   Vol. 109 ( 266 ) page: 71 - 76   2009.10

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In this paper we propose a method for analyzing spatial frequency characteristics of road-vehicle communication. In the proposed communication, we use LED traffic lights as transmitter and high-speed camera on car as receiver. So the distance between LED traffic lights and high-speed camera change from far to near, and as the distance is farther, received pictures are smaller. Therefore it is thought that high frequencies of sending data deteriorate, and Moire occurs in received pictures. In this paper, we analyze the deterioration and confirm improvement of communication using simulation.

    CiNii Article

  468. A Note on Joint Decoding of Correlated Data Observed by Multiple Sensor Nodes : Correlation Estimation According to ADC Bit Levels of Experimentally Observed Data Reviewed

    KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 248 ) page: 95 - 100   2009.10

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In wireless sensor networks, a large number of sensor nodes are densely deployed for reliable environmental sensing. Due to the high density in the sensing field, sensor observations are spatially correlated. In this paper, we focus on joint channel decoding utilizing the spatial correlation of multiple sensor observations. Our proposed scheme makes use of an estimation of the correlation according to ADC bit levels of the sensor observations. The performance of our approach is examined by simulations using sensing data from experiments in a real indoor environment.

    CiNii Article

  469. A Note on Joint Decoding of Correlated Data Observed by Multiple Sensor Nodes : Correlation Estimation According to ADC Bit Levels of Experimentally Observed Data Reviewed

    KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 246 ) page: 121 - 126   2009.10

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    In wireless sensor networks, a large number of sensor nodes are densely deployed for reliable environmental sensing. Due to the high density in the sensing field, sensor observations are spatially correlated. In this paper, we focus on joint channel decoding utilizing the spatial correlation of multiple sensor observations. Our proposed scheme makes use of an estimation of the correlation according to ADC bit levels of the sensor observations. The performance of our approach is examined by simulations using sensing data from experiments in a real indoor environment.

    CiNii Article

  470. An access control scheme for passengers wireless communication systems considering the passing of an opposite train Reviewed

    YAMAMOTO Masahiro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 229 ) page: 89 - 93   2009.10

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    This manuscript discusses on a wireless cellular communication system for railroad passengers, in which base stations are placed along the railroad. In this system, all users or passengers are on trains. Thus there is high concentration in user distribution, and a group of the users on a train move to the same direction with the same speed. In such a system, when two opposite trains enter in the same cell before they pass each other, the number of users in the cell abruptly increases, and forced terminations of communication, i.e. call dropping, may occur due to the concentration of traffic. This paper proposes access control methods that mitigate the probability of the dropping, by limiting the number of channels allowed to use on each train dynamically or statically before the two trains enter the same cell. As a result, it is shown that the probability of the forced termination of an existing call can be decreased with the cost of increase in blocking probability. It is also confirmed that the dynamic access control method can inhibit increasing of the rejection of newly arrived calls compared to the static access control method when the control duration is enough large. In conclusion, the proposed methods provide lower dropping probability than the conventional (no-control) system, under the same blocking probability.

    CiNii Article

  471. M-ary Modulation Scheme Using Separation of Chaotic Dynamics for Noncoherent Chaos-Based Communications Reviewed

    S. ARAI, Y. NISHIO, T. YAMAZATO, S. OZAWA

    2009 International Symposium on Nonlinear Theory and its Applications     page: -   2009.10

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    This paper proposes a new M-ary modulation scheme for noncoherent chaos-based communications. A chaotic sequence is successive based on the chaotic dynamics. Without the successive sequence based on the chaotic dynamics, general noncoherent systems are very difficult to demodulate the data. However, we consider that the systematic separation and the reconstruction of the chaotic dynamics can be applied as additional information. Namely, M-ary data symbols can be expressed by separating the chaotic dynamics purposely. We carry out computer simulations of the proposed scheme and confirm that a saving of over 3-4 dB is realized in transmitter energy by increasing M.

  472. *Visible Light Communications using LED Array and High-Speed Camera for ITS Applications Invited

    T. Yamazato

    IEICE Fundamental Review, Vol.3, No.2, pp.45-53   Vol. Vol.3 ( No.2 ) page: pp.45-53   2009.10

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    Language:Japanese  

  473. A Note on Joint Decoding of Correlated Data Observed by Multiple Sensor Nodes - Correlation Estimation According to ADC Bit Levels of Experimentally Observed Data -

    K. Kobayashi, T. Yamazato, M. Katayama

    Technical Report of IEICE, vol.USN2009-42, pp.95-100   Vol. Vol.USN2009-42   page: pp.95-100   2009.10

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    Language:Japanese  

    In wireless sensor networks, a large number of sensor nodes are densely deployed for reliable environmental sensing. Due to the high density in the sensing field, sensor observations are spatially correlated. In this paper, we focus on joint channel decoding utilizing the spatial correlation of multiple sensor observations. Our proposed scheme makes use of an estimation of the correlation according to ADC bit levels of the sensor observations. The performance of our approach is examined by simulations using sensing data from experiments in a real indoor environment.

  474. Decoding of Separately Encoded Multiple Correlated Sources Transmitted over Noisy Channels Reviewed

    K. Kobayashi, T. Yamazato, M. Katayama

    IEICE Transactions on Fundamentals, vol.E92-A, no.10, pp.2402-2410   Vol. Vol.E92-A ( No.10 ) page: pp.2402-2410   2009.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    We propose an iterative channel decoding scheme for two or more multiple correlated sources. The correlated sources are separately turbo encoded without knowledge of the correlation and transmitted over noisy channels. The proposed decoder exploits the correlation of the multiple sources in an iterative soft decision decoding manner for joint detection of each of the transmitted data. Simulation results show that achieved performance for the more than two sources is also close to the Shannon and Slepian-Wolf limit and large additional SNR gain is obtained in comparison with the case of two sources. We also verify through simulation that no significant penalty results from the estimation of the source correlation in the decoding process and the code with a low error floor achieves good performance for a large number of the correlated sources.

  475. Phase Compensation for Narrowband PLC Channels with Cyclic Time-Varying Features Reviewed

    Y. Sugiura, T. Yamazto, M. Katayama

    Third Workshop on Power Line Communications     page: -   2009.10

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    Phase transfer functions of power-line channels often show sharp and periodic variation synchronous to the (double of) mains frequency. This is a result of impedance change of nonlinear devices connected to the power-lines. This manuscript proposes a phase estimation strategy for phase compensation at a receiver under such environment. In the proposed method, phase estimates are calculated using cyclic observation (average) of the channel phase. The numerical examples under periodic phase variation of the channel and cyclostationary noise show that the receiver with the proposed phase estimation scheme outperforms that with the conventional phase estimation, which uses average over the whole observation period without considering the periodic feature of the channel.

  476. The Receiver for visible Light Road-to-Vehicle Communication

    S. Okada, T. Yendo, T. Yamazato, Hiraku Okada, M. P. Tehrani, T. Fujii, M. Tanimoto

    PCSJ/IMPS 2009     page: -   2009.10

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    Language:Japanese  

    In this paper, we propose a road-to-vehicle visible communication system for ITS. In this system, a LED traffic light is used as transmitter and a photodiode is used as receiver. There are several problems associated with applying visible light communication to the field of ITS. It is necessary to receive information from long distance. And tracking the transmitter for a certain moving distance of the vehicle is also important. We applied an imaging optics to receive information over long distance, and two cameras are used to solve the relationship between the transmitter and the receiver position changes with time, and vibrational correction technique is also fixed to the system to minimize vibrational corrections. We developed algorithms to track the transmitter. The experiments were conducted to confirm the proposals.

  477. Traffic Light Detection for Visible Light Communication Image Sensor

    D Takasao, T. Yendo, T. Yamazato, H. Okada, M. P. Tehrani, T. Fujii, M. Tanimoto

    PCSJ/IMPS 2009     page: -   2009.10

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    The visible light communication used as telecommunications equipment by modulating LED at high speed is researched. And the road-to-vehicle visible light communication applied to the ITS field is researched. In this paper, the visible light communication is done by using a special image sensor. The pixel for the video that can capture video with 30fps and the pixel for the communication that can be communicated at high speed exist in the image sensor. We can detect the position of the traffic light in the image, and communicate by the pixel for the communication. We propose the detection method of the traffic light that makes the best use of the feature of the image sensor.

  478. An access control scheme for passenger wireless communication systems considering the passing of an opposite train

    M. Yamamoto, T. Yamazato, M. Katayama

    Technical Report of IEICE   Vol. Vol.RCS2009-125   page: pp.89-93   2009.10

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    Language:Japanese  

    This manuscript discusses on a wireless cellular communication system for railroad passengers, in which base stations are placed along the railroad. In this system, all users or passengers are on trains. Thus there is high concentration in user distribution, and a group of the users on a train move to the same direction with the same speed. In such a system, when two opposite trains enter in the same cell before they pass each other, the number of users in the cell abruptly increases, and forced terminations of communication, i.e. call dropping, may occur due to the concentration of traffic. This paper proposes access control methods that mitigate the probability of the dropping, by limiting the number of channels allowed to use on each train dynamically or statically before the two trains enter the same cell. As a result, it is shown that the probability of the forced termination of an existing call can be decreased with the cost of increase in blocking probability. It is also confirmed that the dynamic access control method can inhibit increase of the rejection of newly arrived calls compared to the static access control method when the control duration is enough large. In conclusion, the proposed methods provide lower dropping probability than the conventional(no-control) system, under the same blocking probability.

  479. Decoding of Separately Encoded Multiple Correlated Sources Transmitted over Noisy Channels Reviewed

    Kentaro Kobayashi, Takaya Yamazato, Masaaki Katayama

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   Vol. E92A ( 10 ) page: 2402 - 2410   2009.10

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    Publishing type:Research paper (scientific journal)   Publisher:IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

    We propose an iterative channel decoding scheme for two or more multiple correlated sources. The correlated sources are separately turbo encoded without knowledge of the correlation and transmitted over noisy channels. The proposed decoder exploits the correlation of the multiple sources in an iterative soft decision decoding manner for joint detection of each of the transmitted data. Simulation results show that achieved performance for the more than two sources is also close to the Shannon and Slepian-Wolf limit and large additional SNR gain is obtained in comparison with the case of two sources. We also verify through simulation that no significant penalty results from the estimation of the source correlation in the decoding process and the code with a low error floor achieves good performance for a large number of the correlated sources.

    DOI: 10.1587/transfun.E92.A.2402

    Web of Science

    Scopus

    CiNii Article

  480. Bit and power allocation for power-line communications under nonwhite and cyclostationary noise environment Reviewed

    Sawada N.

    2009 IEEE International Symposium on Power Line Communications and its Applications, ISPLC 2009     page: 307 - 312   2009.9

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    Publishing type:Research paper (scientific journal)   Publisher:2009 IEEE International Symposium on Power Line Communications and its Applications, ISPLC 2009  

    DOI: 10.1109/ISPLC.2009.4913448

    Scopus

  481. Luminance Extraction Method for Visible Light Communication System using LED Array and High-Speed Camera

    T. Nagura, T. Yamazato, M. Katayama

    Enginnering Sciences Society Conference of IEICE, A-17-17, p.181   Vol. A-17-17   page: p.181   2009.9

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  482. Impact of Pilot Interpolation Techniques on a Channel Estimation Scheme for Inter-Vehicle Communication

    N. Hiraiwa, T. Yamazato, M. Katayama

    Enginnering Sciences Society Conference of IEICE, A-17-15, p.179   Vol. A-17-15   page: p.179   2009.9

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  483. A study on transmission speed on visible light communication systems using LED array and high-speed camera

    T. Nagura, T. Yamazato, M. Katayama

    Proc. of 11th DSPS Educators Conference, pp.45-46     page: pp.45-46   2009.9

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  484. A Note on Joint Decoding using Correlation Estimation of Multiple Sources according to ADC Bit-Level

    K. Kobayashi, T. Yamazato, M. Katayama

    Communications Society Conference of IEICE, B-20-7, p.388   Vol. B-20-7   page: p.388   2009.9

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  485. Image Processing for Visible Light Communication Using LED Traffic lights

    S. Arai, T. Yamazato, S. Ozawa

    Technical meeting of Electronics, Information and Systems [Division C], IEEJ, Sep., 2009.     page: -   2009.9

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    In this paper, we focus on a road-to-vehicle visible light communications using LED traffic light (transmitter) and an in-vehicle camera (receiver). As advantages using the camera, the recognition of objects as well as their locations can easily be realized and the reception of LED modulated data is also possible at the same time. Unfortunately, if the receiver is far from the transmitter, the received data pattern degrades due to reduction of pixel size and defocusing of the LED data pattern. This paper discusses these problems from image processing approaches.

  486. TOA UWB Position Estimation with Two Receivers and a Set of Known Reflectors Reviewed

    J. KIETLINSKI-ZALESKI, T. YAMAZATO, M. KATAYAMA

    ICUWB 2009 pp.376-380,     page: -   2009.9

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    Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival(ToA) positioning, at least 3 receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel algorithm for ToA positioning using only 2 receivers is presented. This is possible by exploiting reflections from a set of known flat reflectors, for example ceiling and walls. The proposed algorithm was tested using self-developed UWB propagation simulator testbed.

  487. Traffic Prediction Scheme for Resource Assignment of Satellite/Terrestrial Frequency Sharing Mobile Communication System Reviewed

    T. Aman, T. Yamazato, M. Katayama

    International Workshop on Satellite and Space Communications     page: -   2009.9

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    The recent development of large aperture on-board multi-beam antennas enables a small-size, low-powered and cellular phone like hand-held terminal as a satellite earth terminal. A single mobile terminal can communicate to both mobile satellite systems and terrestrial systems depend upon his location, QoS and availability of resources among satellite and terrestrial communication systems. In this paper, we propose a new traffic prediction scheme for the integrated satellite/terrestrial frequency sharing mobile communication system. The system shares a common frequency bandwidth in order to enhance the total capacity by a dynamic bandwidth allocation. A key for this allocation depends on a traffic prediction scheme of a few hundreds of terrestrial cells under a footprint of a satellite with a large aperture onboard multi-beam antennas. We propose three traffic predictors based on neural networks for dynamic resource allocation. The performances of the proposed schemes are evaluated in terms of the Relative Traffic Prediction Error and Maximum Traffic Prediction Error by the computer simulation. For the evaluation, we adopt the actual traffic statistic published by Ministry of Internal Affairs and Communications of Japan with population density of terrestrial cells based on the actual population of Aichi, Japan. As results, average traffic prediction error of less than 0.25 is achieved for the prediction interval of one hour, enough for dynamic resource allocation.

  488. Cognitive Radio with Relay of a Primary Signal and Piggyback Modulation Reviewed

    J. Naganawa, T. Yamazato, M. Katayama

    IEEE International Symposium on Personal, Indoor and Mobile Radio Communication     page: -   2009.9

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    This manuscript proposes a cognitive radio system that shares a frequency with an existing primary system. In the proposed method, a secondary transmitter relays the primary signal and piggybacks its own data on it. Symbol error probabilities of the system are derived analytically. The result shows that the proposed system can communicate at a relatively high speed on the same frequency of the primary system without harm to it.

  489. Detection of LED Traffic Light by Image Processing for Visible Light Communication System Reviewed

    H.C. N. Premachandra, T. Yendo, T. Yamazato, T. Fujii, M. Tanimoto, Y. Kimura

    Proceedings of 2009 IEEE Intelligent Vehicles Symposium (IV'09), June 2009     page: -   2009.8

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    We propose a visible light road-to-vehicle communication system at intersection for ITS. In this system, the communication between vehicle and a LED traffic light is approached using LED traffic light as the transmitter, and on-vehicle high-speed camera as the receiver. The LEDs in the transmitter are emitted with 500Hz and the images of those emitting LEDs are captured by a high-speed camera for conducting communication. In this communication, it is extremely necessary to find the transmitter and detect it for consecutive frames while vehicle is moving. In this paper, we introduce proposals for finding and detecting it for consecutive frames by image processing. Experimental results using appropriate images showed the effectiveness of the proposal.

  490. 巻頭言~創刊500号を迎えて~和文論文誌Bは優れた通信技術・研究を蓄える

    山里敬也

    電子情報通信学会論文誌   Vol. Vol. J92-B ( No. 8 ) page: pp. 1211-1211   2009.8

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  491. An Access Control Method for Multipoint Data Gatheringh over Power-Line Communications Reviewed

    OHTOMO Yuzo, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 144 ) page: 37 - 42   2009.7

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    This paper proposes a media access control method for a multipoint data gathering system using power-line communications. In large-scale power-line communication systems, it is difficult to use a CSMA scheme because of hidden terminal problem. In such condition, by broadcasting acknowledgements, the proposed method ensures assignment of a time slot for each node once the node succeeds to transfer its data to the base-station. It is confirmed that the proposed scheme reduces packet collisions and outperforms conventional slotted-ALOHA scheme in throughput of data. In addition, proposed scheme provides an adaptive slot assignment under cyclo-stationary channel environment.

    CiNii Article

  492. An Access Control Method for Multipoint Data Gathering over Power-Line Communications

    Y. Ohtomo, T. Yamazato, M. Katayama

    Technical Report of IEICE, vol.WBS2009-13, pp.37-42   Vol. Vol.WBS2009-13   page: pp.37-42   2009.7

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    This paper proposes a media access control method for a multipoint data gathering system using power-line communications. In large-scale power-line communication systems, it is difficult to use a CSMA scheme because of hidden terminal problem. In such condition, by broadcasting acknowledgements, the proposed method ensures assignment of a time slot for each node once the node succeeds to transfer its data to the base-station. It is confirmed that the proposed scheme reduces packet collisions and outperforms conventional slotted-ALOHA scheme in throughput of data. In addition, proposed scheme provides an adaptive slot assignment under cyclo-stationary channel environment.

  493. Edge-Based Tracking of an LED Traffic Light for a Road-to-Vehicle Visible Light Communication System Reviewed

    H.C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, T. Fujii, M. Tanimoto, Y. Kimura

    Journal of Broadcast Engineering published by KoSBE, the Korean Society for Broadcast Engineers, Vol. 14, No. 4, pp.475-487, July 2009   Vol. Vol. 14 ( No. 4 ) page: pp.475-487   2009.7

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    We propose a visible light road-to-vehicle communication system at intersection as one of ITS technique. In this system, the communication between vehicle and a LED traffic light is approached using LED traffic light as a transmitter, and on-vehicle high-speed camera as a receiver. The LEDs in the transmitter are emitted in 500Hz and those emitting LEDs are captured by a high-speed camera for making communication. Here, the luminance value of each LED in the transmitter should be found for consecutive frames to achieve effective communication. For this purpose, first the transmitter should be identified, then it should be tracked for consecutive frames while the vehicle is moving, by processing the images from the high-speed camera. In our previous work, the transmitter was identified by getting the subtraction of two consecutive frames. In this paper, we mainly introduce an algorithm to track the identified transmitter in consecutive frames. Experimental results using appropriate images showed the effectiveness of the proposal.

  494. Construction of a Kalman estimator for BFDM/OQAM system in the time-frequency dispersive channels Reviewed

    MONGOL Bayarpurev, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 105 ) page: 125 - 130   2009.6

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    BFDM/OQAM allows to employ a gaussian transmitter pulse at maximal spectral efficiency. Thus, it performs well in the time-frequency dispersive channels and is considered to be a promising candidate for the next generation mobile communications modulation scheme. However, in the highly mobile environment the performance deteriorates and channel equalization and estimation schemes became essential for further improvement of BFDM/OQAM systems. This paper proposes a novel adaptive channel estimator based on a Kalman filter. We approximate the channel state with a number of samples of its fading processes at each delay tap. The idea behind our estimator is to employ a linear predictor to derive a process equation for the Kalman filter. To reduce the convergence time the bayesian estimation is employed to provide an initial value for the Kalman filter. The mean-square-error performance of the proposed estimator is evaluated using computer simulation.

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  495. Channel Estimation and Tracking Schemes for the Pulse-Shaping OFDM Systems Reviewed

    B. Mongol, T. Yamazato, M. Katayama

    IEEE International Conference on Communications, SPC-10-4 (in the CD)   Vol. SPC-10-4   page: -   2009.6

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    Robust channel estimation scheme is essential for pulse-shaping OFDM systems in the multipath mobile environment. This paper proposes three types of channel estimation schemes for the general class of pulse-shaping OFDM systems. The first two types are suboptimal low-complexity maximum likelihood estimators. The last type is adaptive Kalman filter channel estimator. We numerically evaluate the performance of each estimator using computer simulation.

  496. Evaluation and Performance Improvement of a Cooperative Sensing System with Losses of Information from Sensing Nodes Reviewed

    TAKANASHI Makoto, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 61 ) page: 75 - 79   2009.5

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    At a location and time, there may be frequencies not in use by their licensed (primary) users. Spectrum sharing, in which a secondary radio system uses such white spaces of frequency, is one of advantageous means to mitigate the spectrum scarcity. In order to realize the spectrum sharing, spectrum sensing that detects the presence of a primary user signal is a key technology. For reliable sensing of the primary signal, cooperative sensing where information from multiple sensing nodes is incorporated at a fusion center is currently being investigated by many researchers. Majority of these works consider the imperfectness of the channels between a primary transmitter and sensor nodes under noise and fading environments. On the contrary, this manuscript deals with the transmission between sensor nodes to a fusion center. For a cooperative spectrum sensing system, in which the analog outputs of energy detectors at sensor nodes are transmitted to a fusion center, the influence of losses of information from the nodes on detection performance is derived analytically. In addition, it is shown that the adaptive processing with the consideration of information loss at the fusion center improves system performance.

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  497. No Redundant Error-Correcting Scheme Using Chaotic Dynamics for Noncoherent Chaos Communications Reviewed

    S. Arai, Y. Nishio, T. Yamazato

    Proceedings of 2009 IEEE International Symposium on Circuits and Systems, pp. 2633-2636     page: pp. 2633-2636   2009.5

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    This paper proposes the error-correcting scheme without redundancy sequences based on the chaotic dynamics for noncoherent chaos communications. We generate successive chaotic sequences from the identical chaotic map. And for the next sequence we set the initial value to the end value of the former sequence. By such way we can create the successive chaotic sequences having the same chaotic dynamics. This feature gives the receiver additional information to correctly recover the received noisy signal. Therefore, by analyzing the chaotic dynamics at the receiver, it is possible to improve the error performance without redundancy signal. As results of computer simulations, we confirm about 3 dB gain in BER performance as compared with the conventional suboptimal receiver when using the short chaotic sequence length per 1 bit.

  498. Evaluation and Performance Improvement of a Cooperative Sensing System with Losses of Information from Sensing Nodes

    M. Takanashi, T. Yamazato, M. Katayama

    Technical Report of IEICE, vol.109, no.61 (SR2009-5), pp.75-79,   Vol. Vol.109 ( No.61 (SR2009-5) ) page: -   2009.5

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    At a location and time, there may be frequencies not in use by their licensed (primary) users. Spectrum sharing, in which a secondary radio system uses such white spaces of frequency, is one of advantageous means to mitigate the spectrum scarcity. In order to realize the spectrum sharing, spectrum sensing that detects the presence of a primary user signal is a key

  499. Joint decoding scheme using bit-level correlation of experimentally observed data

    K. Kobayashi, T. Yamazato, M. Katayama

    Technical Report of IEICE, vol.MoMuC2009-2, pp.7-12   Vol. Vol.MoMuC2009-2   page: pp.7-12   2009.5

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    In wireless sensor networks, a large number of sensor nodes are densely deployed for a reliable sensing of physical phenomenon. Due to the high density in the sensing field, sensor observations are spatially correlated. In this paper, we focus on joint channel decoding schemes utilizing the correlation of sensor observations. Our proposed scheme makes use of a bit-level correlation property of data observed in the real environment. The performance of our approach is examined by simulations using sensing data from experiments in a real indoor environment.

  500. Joint decoding scheme using bit-level correlation of experimentally observed data Reviewed

    KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 109 ( 22 ) page: 7 - 12   2009.4

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    In wireless sensor networks, a large number of sensor nodes are densely deployed for a reliable sensing of physical phenomenon. Due to the high density in the sensing field, sensor observations are spatially correlated. In this paper, we focus on joint channel decoding schemes utilizing the correlation of sensor observations. Our proposed scheme makes use of a bit-level correlation property of data observed in the real environment. The performance of our approach is examined by simulations using sensing data from experiments in a real indoor environment.

    CiNii Article

  501. Bit and Power Allocation for Power-Line Communications under Nonwhite and Cyclostationary Noise Environment Reviewed

    N. Sawada, T. Yamazato, M. Katayama

    IEEE International Symposium on Power Line Communications and Its Applications     page: -   2009.4

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    This manuscript discusses the adaptive OFDM system for narrow-band power-line communications with nonwhite and cyclostationary noise environment. The bit and power allocation algorithm is proposed with the considerations on the cyclostationarity of power-line noise. Numerical evaluation shows that the proposed method can improve the average BER performance under PLC noise environment.

  502. B-20-42 ISOMAC based energy efficient TDMA-MAC protocol for Sensor Networks Reviewed

    CHEN Hiroshi, YAMAZATO Takaya, KATAYAMA Masaaki

    Proceedings of the IEICE General Conference   Vol. 2009 ( 2 )   2009.3

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  503. 1つの既知反射面と2つの受信機によるUWB ToA位置推定 Reviewed

    キエトリンスキ ザレスキ ヤン, 山里 敬也, 片山 正昭

    電子情報通信学会技術研究報告. WBS, ワイドバンドシステム : IEICE technical report   Vol. 108 ( 474 ) page: 211 - 216   2009.3

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    Publishing type:Research paper (scientific journal)   Publisher:一般社団法人電子情報通信学会  

    UWBは近距離,特に室内での位置推定のための技術として注目を集めている.しかし,通常用いられるTime of Arrival(ToA)による位置推定では,送信機からの直接波が最低でも3つの異なる位置にある受信機で必要になる.一般に,そのような条件が必ず満たされる訳では無い.本稿では,2つの異なる位置にある受信機を用いたToAによる新しい位置推定手法について提案する.提案手法では,例えば天井や壁などの,ある1つの平面に関する情報が既知であると仮定することで位置推定を実現する.提案するアルゴリズムは,新たに作成したUWB伝搬シミュレーターによって評価する.

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  504. Phase Compensation for Narrowband Power-Line Communication Channels with Cyclic Time-Varying Features Reviewed

    SUGIURA Yoshie, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 108 ( 473 ) page: 513 - 518   2009.3

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    Phase transfer functions of power-line channels often show sharp and periodic variation synchronous to the (double of) mains frequency. This is a result of impedance change of nonlinear devices connected to the power-lines. This manuscript proposes a phase estimation strategy for phase compensation at a receiver under such environment. In the proposed method, phase estimates are calculated using cyclic observation (average) of the channel characteristics. The numerical examples under periodic phase variation of the channel and cyclostationary noise, show that the receiver with the proposed phase estimation scheme outperforms that with the conventional phase estimation which uses average over the whole observation period without considering the periodic feature of the channel.

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  505. Influence of channel errors on a wireless-controlled rotary inverted pendulum Reviewed

    KOHINATA Reo, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 108 ( 472 ) page: 167 - 172   2009.3

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    This paper discusses the influence of channel features to the performance of a wireless-controlled system. As an example of the system, a rotary inverted pendulum that has wireless connections in its feedback loop between a controller and the controlled system. As for the wireless channels, both a random error model and a burst error model are employed and the effects of transmission rate and errors to the control quality are evaluated. As a result, it is confirmed that the system with transmission errors can keep the pendulum stable when data rate of the communication is enough high and error rate is below a certain level. In addition, it is clarified that that burst errors in wireless channels affect more when the control quality is kept by compensating errors with higher transmission rate.

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  506. Influence of channel errors on a wireless-controlled rotary inverted pendulum Reviewed

    KOHINATA Reo, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 108 ( 474 ) page: 167 - 172   2009.3

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    This paper discusses the influence of channel features to the performance of a wireless-controlled system. As an example of the system, a rotary inverted pendulum that has wireless connections in its feedback loop between a controller and the controlled system. As for the wireless channels, both a random error model and a burst error model are employed and the effects of transmission rate and errors to the control quality are evaluated. As a result, it is confirmed that the system with transmission errors can keep the pendulum stable when data rate of the communication is enough high and error rate is below a certain level. In addition, it is clarified that that burst errors in wireless channels affect more when the control quality is kept by compensating errors with higher transmission rate.

    CiNii Article

  507. Influence of channel errors on a wireless-controlled rotary inverted pendulum Reviewed

    KOHINATA Reo, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 108 ( 473 ) page: 167 - 172   2009.3

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    This paper discusses the influence of channel features to the performance of a wireless-controlled system. As an example of the system, a rotary inverted pendulum that has wireless connections in its feedback loop between a controller and the controlled system. As for the wireless channels, both a random error model and a burst error model are employed and the effects of transmission rate and errors to the control quality are evaluated. As a result, it is confirmed that the system with transmission errors can keep the pendulum stable when data rate of the communication is enough high and error rate is below a certain level. In addition, it is clarified that that burst errors in wireless channels affect more when the control quality is kept by compensating errors with higher transmission rate.

    CiNii Article

  508. Phase Compensation for Narrowband Power-Line Communication Channels with Cyclic Time-Varying Features Reviewed

    SUGIURA Yoshie, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 108 ( 472 ) page: 513 - 518   2009.3

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    Phase transfer functions of power-line channels often show sharp and periodic variation synchronous to the (double of) mains frequency. This is a result of impedance change of nonlinear devices connected to the power-lines. This manuscript proposes a phase estimation strategy for phase compensation at a receiver under such environment. In the proposed method, phase estimates are calculated using cyclic observation (average) of the channel characteristics. The numerical examples under periodic phase variation of the channel and cyclostationary noise, show that the receiver with the proposed phase estimation scheme outperforms that with the conventional phase estimation which uses average over the whole observation period without considering the periodic feature of the channel.

    CiNii Article

  509. Phase Compensation for Narrowband Power-Line Communication Channels with Cyclic Time-Varying Features Reviewed

    SUGIURA Yoshie, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 108 ( 474 ) page: 513 - 518   2009.3

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Phase transfer functions of power-line channels often show sharp and periodic variation synchronous to the (double of) mains frequency. This is a result of impedance change of nonlinear devices connected to the power-lines. This manuscript proposes a phase estimation strategy for phase compensation at a receiver under such environment. In the proposed method, phase estimates are calculated using cyclic observation (average) of the channel characteristics. The numerical examples under periodic phase variation of the channel and cyclostationary noise, show that the receiver with the proposed phase estimation scheme outperforms that with the conventional phase estimation which uses average over the whole observation period without considering the periodic feature of the channel.

    CiNii Article

  510. Traffic Prediction Scheme for Resource Assignment of Satellite/Terrestrial Frequency Sharing Mobile Communication System Reviewed

    AMAN Tomohiro, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 108 ( 440 ) page: 55 - 60   2009.2

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    Satellite/Terrestrial Frequency Sharing Mobile Communication System is drawing an attention for interpolation between satellite mobile communication and terrestrial mobile communication and improvement of spectrum utilization efficiency. Spectrum utilization efficiency can be improved in this system by sharing common frequency bands in satellite mobile and terrestrial mobile communication system and using dynamic resource assignment. But it is need to traffic prediction for dynamic resource assignment. This report propose traffic prediction method using neural network.

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  511. 衛星/地上周波数共用移動通信システムに置ける資源割当てのためのトラヒック予測

    阿萬友洋,山里敬也, 片山正昭

    電子情報通信学会技術研究報告     page: -   2009.2

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    協力通信は複数の無線ノードが協力して同一の情報を送信することにより伝送距離を延長し,各ノードの消費電力を低減できる.本稿では,複数のクラスタに分割された無線センサネットワークに協力通信を適用することを考える.クラスタ間協力通信を行うには同一クラスタ内の複数のノードで情報を共有しなければならず,そのためにはクラスタヘッドに選出されたノードがクラスタ内に情報をブロードキャストする必要がある.しかし,このクラスタヘッドの選出手法によりネットワーク全体の消費電力が左右される.そこで,センサネットワークの稼働時間の延長を目的とし,各ノードの残余電力を考慮したクラスタヘッドの選出手法を提案する.結果より,提案手法はセンサノード稼働率,Outage確率共に改善可能であることを示す.

  512. Cluster-based Cooperative Transmission considering the Residual Power of Wireless Sensor Nodes Reviewed

    TAKESHIMA Koki, YAMAZATO Takaya, KATAYAMA Masaaki

    IEICE technical report   Vol. 108 ( 399 ) page: 83 - 87   2009.1

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    Cooperative transmission can extend the transmission range by transmitting the same data from multiple wireless nodes, and consequently can reduce the consumed power of each node. In this paper, we apply the cooperative transmission to a wireless sensor network where the sensor nodes are organized into multiple clusters. To perform the cluster-based cooperative transmission, it has to choose a cluster head which broadcasts its decoded data to other nodes in a cluster. The overall dissipation power is, however, governed by the cluster head selection criterion. In this paper, we propose a simple cluster head selection criterion considering the residual power of each sensor node, and aim to extend the network lifetime. As results, the proposed scheme shows the best in the active sensor node rate and outage probability.

    CiNii Article

  513. Turbo Equalization for Inter-Vehicle Communication Based on MC-CDMA Reviewed

    HIRAIWA Noriaki, SAKATA Atsunori, YAMAZATO Takaya, KATAYAMA Masaaki

    The IEICE transactions on communications B   Vol. 92 ( 1 ) page: 367 - 369   2009.1

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  514. Tracking an LED Array Using Optical Flow for Visible Light Communication System

    H. Chinthaka N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto

    2009 ITE Winter Annual Convention     page: -   2009.1

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    We propose a visible light road-to-vehicle communication system at intersection as one of ITS technique. In this system, the communication between vehicle and an LED array is approached using LED array as a transmitter, and on-vehicle high-speed camera as a receiver. The LEDs in the transmitter are emitted in 500Hz and those emitting LEDs are captured by a high-speed camera for making communication. Here, the luminance value of LEDs in the transmitter should be captured in consecutive frames to achieve effective communication. For this purpose, first the transmitter should be identified, then it should be tracked in consecutive frames while the vehicle is moving, by processing the images from the high-speed camera. In this paper, we mainly introduce an algorithm to track the transmitter using optical flow and edge information.

  515. Cluster-based Cooperative Transmission considering Residual Power of Wireless Sensor Nodes

    K. Takeshima, T. Yamazato, M. Katayama

    Technical Report of IEICE   Vol. USN2008-76   page: 83-87   2009.1

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    In this letter, we propose a new SC/MMSE Turbo equalizer for inter-vehicle communication based on MC-CDMA. We modify the MMSE filter in SC/MMSE Turbo equalizer focusing on the difference of channel transfer function of each car. As results, we show that better performance is obtained.

  516. Turbo Equalization for Inter-Vehicle Communication based on MC-CDMA Reviewed

    N. Hiraiwa, A. Sakata, T. Yamazato, M. Katayama

    IEICE Transactions on Communications   Vol. J92-B ( 1 ) page: 367-369   2009.1

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  517. 10-219 Nagoya Univeristy OCW Reviewed

    Yamazato Takaya

    Proceedings of Annual Conference of Japanese Society for Engineering Education   Vol. 2009 ( 0 ) page: 416 - 417   2009

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    DOI: 10.20549/jseejaarc.2009.0_416

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  518. 4-5 オプティカルフローを用いた可視光通信システムためのLEDアレイ追跡(第4部門 ヒューマンインフォメーション1) Reviewed

    プレーマチャンドラ チンタカ, 圓道 敬也, パナヒプル テヘラニ メヒルダド, 山里 敬也, 岡田 啓, 藤井 俊彰, 谷本 正幸

    映像情報メディア学会冬季大会講演予稿集   Vol. 2009 ( 0 ) page: _4 - 5-1_   2009

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    Publishing type:Research paper (scientific journal)   Publisher:一般社団法人 映像情報メディア学会  

    We propose a visible light road-to-vehicle communication system at intersection as one of ITS technique. In this system, the communication between vehicle and an LED array is approached using LED array as a transmitter, and on-vehicle high-speed camera as a receiver. The LEDs in the transmitter are emitted in 500Hz and those emitting LEDs are captured by a high-speed camera for making communication. Here, the luminance value of LEDs in the transmitter should be captured in consecutive frames to achieve effective communication. For this purpose, first the transmitter should be identified, then it should be tracked in consecutive frames while the vehicle is moving, by processing the images from the high-speed camera. In this paper, we mainly introduce an algorithm to track the transmitter using optical flow and edge information.

    DOI: 10.11485/itewac.2009.0__4-5-1_

    CiNii Article

  519. Channel Estimation and Tracking Schemes for the Pulse-Shaping OFDM Systems Reviewed

    Mongol Bayarpurev, Yamazato Takaya, Katayama Masaaki

    2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8     page: 3076 - 3080   2009

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  520. Channel Estimation and Tracking Schemes for the Pulse-Shaping OFDM Systems Reviewed

    Bayarpurev Mongol, Takaya Yamazato, Masaaki Katayama

    2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8     page: 3076 - 3080   2009

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    Robust channel estimation scheme is essential for pulse-shaping OFDM systems in the multipath mobile environment. This paper proposes three types of channel estimation schemes for the general class of pulse-shaping OFDM systems. The first two types are suboptimal low-complexity, maximum likelihood estimators. The last type is adaptive Kalman filter channel estimator. We numerically evaluate the performance of each estimator using computer simulation.

    DOI: 10.1109/ICC.2009.5198817

    Web of Science

  521. Channel estimation and tracking schemes for the pulse-shaping OFDM systems Reviewed

    Bayarpurev Mongol, Takaya Yamazato, Masaaki Katayama

    IEEE International Conference on Communications     2009

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    Language:English   Publishing type:Research paper (international conference proceedings)  

    Robust channel estimation scheme is essential for pulse-shaping OFDM systems in the multipath mobile environment. This paper proposes three types of channel estimation schemes for the general class of pulse-shaping OFDM systems. The first two types are suboptimal low-complexity maximum likelihood estimators. The last type is adaptive Kalman filter channel estimator. We numerically evaluate the performance of each estimator using computer simulation. ©2009 IEEE.

    DOI: 10.1109/ICC.2009.5198817

    Scopus

  522. Cognitive Radio with Relay of a Primary Signal and Piggyback Modulation Reviewed

    Naganawa Jun, Yamazato Takaya, Katayama Masaaki

    2009 IEEE 20TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS     page: 147 - 151   2009

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    Publishing type:Research paper (scientific journal)  

    Web of Science

  523. Cognitive Radio with Relay of a Primary Signal and Piggyback Modulation Reviewed

    Jun Naganawa, Takaya Yamazato, Masaaki Katayama

    2009 IEEE 20TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS     page: 147 - 151   2009

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    This manuscript proposes a cognitive radio system that shares a frequency with an existing primary system. In the proposed method, a secondary transmitter relays the primary signal and piggybacks its own data on it. Symbol error probabilities of the system are derived analytically. The result shows that the proposed system can communicate at a relatively high speed on the same frequency of the primary system without harm to it.

    DOI: 10.1109/PIMRC.2009.5450056

    Web of Science

    Scopus

  524. A-17-17 Luminance Extraction Method for Visible Light Communication System using LED Array and High-Speed Camera Reviewed

    NAGURA Toru, YAMAZATO Takaya, KATAYAMA Masaaki

    Proceedings of the Society Conference of IEICE     2009

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    CiNii Article

  525. On-Vehicle Receiver for Road-to-Vehicle Communication System Reviewed

    OKADA Satoshi, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, TEHRANI Mehrdad Panahpour, FUJII Toshiaki, TANIMOTO Masayuki

    ITE Technical Report   Vol. 33 ( 0 ) page: 77 - 81   2009

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    Publishing type:Research paper (scientific journal)   Publisher:The Institute of Image Information and Television Engineers  

    We consider an on-vehicle receiving system for long-distance and high-speed visible light communication. There are several problems associated with applying visible light communication to the field of ITS. It is necessary to receive information from long distance. And tracking the transmitter for a certain moving distance of the vehicle is also important. We applied an imaging optics to receive information over long distance, and two cameras are used to solve the relationship between the transmitter and the receiver position changes with time, and vibrational correction technique is also fixed to the system to minimize vibrational affections

    DOI: 10.11485/itetr.33.55.0_77

    CiNii Article

  526. Visible Light Communications Using LED Array and High-speed Camera for ITS Applications Reviewed

    YAMAZATO Takaya

    IEICE ESS Fundamentals Review   Vol. 3 ( 2 ) page: 45 - 53   2009

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    Pu