Papers - YAMAZATO Takaya

A modulation scheme for a cognitive radio system to overlay on a secondary user

Jun Naganawa, Takaya Yamazato, Masaaki Katayama

Technical Report of IEICE   Vol. SR2008-2   page： -   2008.5

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As an answer to increasing demands for frequency spectrum, secondary spe ctrum licensing, in which a secondary wireless system overlays on the fr equency band of an existing primary system, is taking attention. In ove rlay communications, the secondary system is demanded not to be a cause of performance degradation of the primary system, while the primary syst em does not considers the secondary system. This manuscript proposes a modulation scheme for such a secondary system . In the proposed scheme, the secondary system modifies its transmitting signal parameters adapting channel states and transmitted signal of the primary system. This set of reference information is also used at the r eceiver of the secondary system. We derive the symbol error rates of both the systems analytically, and s how that it is possble to realize the communication of the secondary sys tem with the same quality as the primary system, which has any degradati on by the signal of the secondary system.

Spatial Diversity Scheme with Multiple-Transmit/Receive Antennas and Relay Terminals for Reliable Wireless Control Reviewed

R. Uchida, H. Okada, T. Yamazato, M. Katayama

IEICE Transactions on Communications   Vol. J91-B ( 5 ) page： 585-594 - 594   2008.5

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

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Other Link： http://hdl.handle.net/2237/12646

Measurement of Narrowband Channel Characteristics in Single-Phase Three-Wire Indoor Power-Line Channels Reviewed

Y. Sugiura, T. Yamazato, M. Katayama

IEEE International Symposium on Power Line Communications and Its Applications     page： -   2008.4

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This manuscript reports the measurement results of narrowband signal propagation of PLC channels. In Japan, in-house wiring is single-phase three-wire, and each branch between an outlet of 100V and the panel board is connected to one of two live conductors and the neutral. Thus a pair of outlets can be classified into three types: connected to different live conductors, connected to the same live conductors by different branches from the panel board, and on the same branch to the same live conductor. It is confirmed that the results of the measurements can be classified by these three types of paths. The results show that frequency responses of narrowband PLC channels are relatively smooth, compared with that of wideband PLC. It is also found that propagation loss in lower frequency range is larger than in higher frequency range. The time independence of narrowband PLC channels are confirmed when no electric appliance is connected to the same live conductor.

A-17-12 CDMA Slotted ALOHA Systems with Successive Interference Cancellation for Inter-Vehicle Communications(A-17. ITS) Reviewed

Sakata Atsunori, Yamazato Takaya, Okada Hiraku, Katayama Masaaki

Proceedings of the IEICE General Conference   Vol. 2008   page： 323   2008.3

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

CiNii Research

A-5-18 Adaptive modulation for power-line communications with nonwhite and cyclostationary noise Reviewed

Sawada Naoya, Yamazato Takaya, Katayama Masaaki

Proceedings of the IEICE General Conference   Vol. 2008   page： 145   2008.3

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

CiNii Research

A-2-35 Noncoherent Communication Systems using Chaotic Sequence with Many Biased Values Reviewed

ARAI Shintaro, NISHIO Yoshifumi, YAMAZATO Takaya

Proceedings of the IEICE General Conference   Vol. 2008   page： 74   2008.3

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

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Introduction of Fractional Frequency Reuse and Fast Retrial Algorithm for uplink of Multi-Cell OFDMA s-ALOHA systems

K. Kimura T. Yamazato, M. Katayama

IEICE General Conference     page： -   2008.3

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Iterative joint decoding of multiple correlated sources using Turbo codes

K. Kobayashi, T. Yamazato, M. Katayama

IEICE General Conference     page： -   2008.3

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Carrier Assignment to Improve the Transmission Efficiency of Edge Terminal in OFDMA Downlink Cellular System

M. Fushiki, T. Yamazato, M. Katayama

IEICE General Conference     page： -   2008.3

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Autonomous Collision-less Slot Assignment Algorithm for Wireless Sensor Networks

R. Chandradasa, T. Yamazato, M. Katayama

IEICE General Conference     page： -   2008.3

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Traditional MAC protocols for Sensor Networks are mostly based on random access methods, which cause message collision and energy loss. Several TDMA based methods have been proposed to prevent signal collision with the help of a base station. We propose an algorithm which assigns time slots to sensor nodes without the help of a base station and realizes time-slot reuse.

CDMA slotted ALOHA Systems with Successive Interference Cancellation for Inter-Vehicle Communications

A.Sakata, T.Yamazato, H.Okada, M.Katayama

IEICE General Conference     page： -   2008.3

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Performance Comparison of SC/MMSE Turbo Equalization and MMSE Equalization in Inter-Vehicle Communication using MC-CDMA

N. Hiraiwa, A. Sakata, T. Yamazato, M. Katayama

IEICE General Conference     page： -   2008.3

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Time Variation of Narrowband Channel Characteristics of Indoor Power-Line Channels

Y. Sugiura T. Yamazato, M. Katayama

IEICE General Conference     page： -   2008.3

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Adaptive modulation for power-line communications with nonwhite and cyclostationary noise

N. Sawada, T. Yamazato, M. Katayama

IEICE General Conference     page： -   2008.3

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Performance Improvement of Downlink MC-CDMA Cellular System with an Intermittent Transmission Reviewed

M.Fushiki, T.Yamazato, M.Katayama

IEEE Radio and Wireless Symposium     page： -   2008.1

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Throughput performance of MC-CDMA systems depends on the success in managing interference arising from intercell transmission. In this paper, we propose a new intercell interference mitigation scheme for downlink MC-CDMA scheme. In the proposed scheme, a base station transmits downlink signals intermittently to mobile terminals at the edge of cell. The intercell interference can be seen as a partial interference depend upon the on and off period of the adjacent downlink signals. So it is possible for the channel equalizer to suppress this partial intercell interference by setting the weight changes in accordance with the intercell interference. As results, the frame error rate of the proposed scheme is always better than that of the conventional scheme and good throughput performance is achieved especially when the traffic is high.

A New SC/MMSE Turbo Equalization for MC-CDMA to use in Inter-Vehicle Communication Reviewed

Hiraiwa Noriaki, Sakata Atsunori, Yamazato Takaya, Katayama Masaaki

68TH IEEE VEHICULAR TECHNOLOGY CONFERENCE, FALL 2008     page： 1193 - 1197   2008

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Web of Science

A route establishment scheme for multi-route coding in multihop cellular networks Reviewed

Hiraku Okada, Hitoshi Imai, Takaya Yamazato, Masaaki Katayama, Kenichi Mase

Journal of Networks   Vol. 3 ( 7 ) page： 34 - 40   2008

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

Since the network topology in multihop cellular networks is flexible, multiple routes from a user station to a base station can be established. To reduce packet reception errors of wireless links, a multi-route coding scheme was proposed. An important issue of the multi-route coding is to develop an efficient route establishment scheme. In this paper, we propose a route establishment scheme for multi-route coding in multihop cellular networks. Our proposed scheme consists of a route selection method based on the bit error rate of each wireless link and a hybrid-type multipletree routing protocol. We evaluate the performance of our proposed scheme by a computer simulation and show the resulting improvement in the packet error. © 2008 Academy Publisher.

DOI： 10.4304/jnw.3.7.34-40

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Bit and Power Allocation for Power-Line Communications under Nonwhite and Cyclostationary Noise Environment Reviewed

Sawada Naoya, Yamazato Takaya, Katayama Masaaki

ISPLC: 2009 IEEE INTERNATIONAL SYMPOSIUM ON POWER LINE COMMUNICATIONS AND ITS APPLICATIONS     page： 307 - +   2008

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Bit and Power Allocation for Power-Line Communications under Nonwhite and Cyclostationary Noise Environment Reviewed

Naoya Sawada, Takaya Yamazato, Masaaki Katayama

ISPLC: 2009 IEEE INTERNATIONAL SYMPOSIUM ON POWER LINE COMMUNICATIONS AND ITS APPLICATIONS     page： 307 - +   2008

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

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.

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Energy Efficiency of Cooperative MISO Technique in Multi-Hop Wireless Sensor Networks Reviewed

Huang Zheng, Yamazato Takaya, Katayama Masaaki

ISSNIP 2008: PROCEEDINGS OF THE 2008 INTERNATIONAL CONFERENCE ON INTELLIGENT SENSORS, SENSOR NETWORKS, AND INFORMATION PROCESSING     page： 511 - +   2008

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Web of Science