Faculty Profiles - YAMAZATO Takaya

Papers - YAMAZATO Takaya

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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 page： 79 2012.3

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 page： 80 2012.3

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

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

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.

CiNii Research

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

Language：Japanese

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.

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

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 Research

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

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

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

CiNii Research

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

Gaussian Pulse Shape Optimization of BFDM in Highly Mobile Environments Reviewed Open Access

D. Goto, T. Yayazato, B. Mongol

IEICE Transactions on Communications Vol. J95-B ( 2 ) page： 317-325 2012.2

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

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.

Open Access

Cooperative Transmission Scheme with the Reactivation Condition of Inactive Nodes in Solar-Powered Wireless Sensor Networks Reviewed Open Access

K. Ota, K. Kobayashi, T. Yamazato, M. Katayama

IEICE Transactions on Communications Vol. J95-B ( 2 ) page： 246-256 2012.2

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

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.

Open Access

Cooperative Transmission Scheme with the Reactivation Condition of Inactive Nodes in Solar-Powered Wireless Sensor Networks Reviewed Open Access

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

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

Gaussian Pulse Shape Optimization of BFDM in Highly Mobile Environments Reviewed Open Access

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

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

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

Language：English 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

[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

Language：Japanese

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.

Decline in Probability of False Recognition of Non-Information Sources in Visible Light Communication for Intelligent Transport System Open Access

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

Technical Report of IEICE Vol. USN2011-59 page： 13-18 2012.1

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

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

CiNii Research

Real-Time Data Transmission of Road-to-Vehicle Visible Light Communication System Using LED Array and High-Speed Camera Reviewed Open Access

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

Vol. 111 ( 386 ) page： 173 - 175 2012.1

Real-Time Data Transmission of Road-to-Vehicle Visible Light Communication System Using LED Array and High-Speed Camera Reviewed Open Access

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

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

Open Access

CiNii Research

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Papers - YAMAZATO Takaya