Faculty Profiles - YAMAZATO Takaya

Papers - YAMAZATO Takaya

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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

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

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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

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

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

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Channel estimation and tracking schemes for the pulse-shaping OFDM systems Reviewed

Bayarpurev Mongol, Takaya Yamazato, Masaaki Katayama

IEEE International Conference on Communications 2009

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

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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

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

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

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

A-17-19 Detection of Luminance for Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera Reviewed

ARAI Shintaro, MASE Shohei, NAGURA Toru, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, TANIMOTO Masayuki, KIMURA Yoshikatsu

Proceedings of the IEICE General Conference Vol. 311 2009

A-17-18 128k Transmission of Visible Light Communication System using LED Array and High-Speed Camera Reviewed

NAGURA Toru, MASE Shohei, ARAI Shintaro, YAMAZATO Takaya, YENDO Tomohiro, FUJII Toshiaki, TANIMOTO Masayuki, KIMURA Yoshikatsu

Proceedings of the IEICE General Conference Vol. 310 2009

No Redundant Error-Correcting Scheme Using Chaotic Dynamics for Noncoherent Chaos Communications Reviewed

Arai Shintaro, Nishio Yoshifumi, Yamazato Takaya

ISCAS: 2009 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOLS 1-5 page： 2633 - + 2009

On-Vehicle Receiver for Distant Visible Light Road-to-Vehicle Communication Reviewed

Satoshi Okada, Tomohiro Yendo, Takaya Yamazato, Toshiaki Fujii, Masayuki Tanimoto, Yoshikatsu Kimura

2009 IEEE INTELLIGENT VEHICLES SYMPOSIUM, VOLS 1 AND 2 page： 1033 - 1038 2009

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

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 affections. We developed algorithms to track the transmitter. The experiments were conducted to confirm the proposals.

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No Redundant Error-Correcting Scheme Using Chaotic Dynamics for Noncoherent Chaos Communications Reviewed

Shintaro Arai, Yoshifumi Nishio, Takaya Yamazato

ISCAS: 2009 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOLS 1-5 page： 2633 - + 2009

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

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.

DOI： 10.1109/ISCAS.2009.5118342

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TOA UWB Position Estimation with Two Receivers and a Set of Known Reflectors Reviewed

Kietlinski-Zaleski Jan, Yamazato Takaya, Katayama Masaaki

2009 IEEE INTERNATIONAL CONFERENCE ON ULTRA-WIDEBAND (ICUWB 2009) page： 376 - + 2009

A-17-15 Impact of Pilot Interpolation Techniques on a Channel Estimation Scheme for Inter-Vehicle Communication Reviewed

HIRAIWA Noriaki, YAMAZATO Takaya, KATAYAMA Masaaki

Proceedings of the Society Conference of IEICE Vol. 179 2009

Traffic Prediction Scheme for Resource Assignment of Satellite/Terrestrial Frequency Sharing Mobile Communication System Reviewed

Tomohiro Aman, Takaya Yamazato, Masaaki Katayama

2009 INTERNATIONAL WORKSHOP ON SATELLITE AND SPACE COMMUNICATIONS, CONFERENCE PROCEEDINGS page： 40 - + 2009

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

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 on-board 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.

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Traffic Prediction Scheme for Resource Assignment of Satellite/Terrestrial Frequency Sharing Mobile Communication System Reviewed

Aman Tomohiro, Yamazato Takaya, Katayama Masaaki

2009 INTERNATIONAL WORKSHOP ON SATELLITE AND SPACE COMMUNICATIONS, CONFERENCE PROCEEDINGS page： 40 - + 2009

TOA UWB Position Estimation with Two Receivers and a Set of Known Reflectors Reviewed

Jan Kietlinski-Zaleski, Takaya Yamazato, Masaaki Katayama

2009 IEEE INTERNATIONAL CONFERENCE ON ULTRA-WIDEBAND (ICUWB 2009) page： 376 - + 2009

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 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.

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B-20-7 A Note on Joint Decoding using Correlation Estimation of Multiple Sources according to ADC Bit-Level Reviewed

KOBAYASHI Kentaro, YAMAZATO Takaya, KATAYAMA Masaaki

Proceedings of the Society Conference of IEICE Vol. 388 2009

CDMA slotted ALOHA system with successive interference cancellation for inter-vehicle communications Reviewed

Sakata A.

IEEE International Symposium on Spread Spectrum Techniques and Applications page： 188 - 193 2008.12

Mitigation of Satellite Non-linear Effect Using SLM and Iterative Distortion Compensation for OFDM in Satellite Channel Reviewed

AMAN Tomohiro, YAMAZATO Takaya, KATAYAMA Masaaki, OGAWA Akira

The IEICE transactions on communications B Vol. 91 ( 12 ) page： 1644 - 1646 2008.12

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Papers - YAMAZATO Takaya