Faculty Profiles - YAMAZATO Takaya

Papers - YAMAZATO Takaya

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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

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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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

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

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

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

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Global Communications Newsletter. Reviewed

Stefano Bregni, Takaya Yamazato, Vasile Bota,Liangping Ma

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

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

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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

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

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

Modulation and Coding For Image Sensor Communication

Kamakura Koji, Yamazato Takaya

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

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

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

V2X communications with an image sensor. Reviewed

Takaya Yamazato

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

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 2016.7

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

This paper discusses the stochastic resonance (SR) effect in a binary communication system for subthreshold signal reception. We focus on the problem of no communication when received signal strength is below receiver sensitivity. Subthreshold signal reception requires a device that exhibits SR, such as a Schmitt trigger or a comparator. Previously, we proposed an alternative three-level device and demonstrated its high performance for subthreshold signal reception in an SR receiver. In the present study, we show that our proposed three-level device outperforms the three devices and discuss reasons for this superior performance. Contributions of our present paper are twofold: first, we analytically derive bit error rate (BER) performances of SR receivers installed with a Schmitt trigger and a comparator;second, we compare performances of the Schmitt trigger, comparator, and three-level device.

DOI： 10.1587/nolta.7.407

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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

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

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 < 10(-5).

DOI： 10.1109/JPHOT.2016.2555582

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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 page： 194 2016.3

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 page： 153 2016.3

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

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

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

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

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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Papers - YAMAZATO Takaya