研究者詳細 - 山里　敬也

論文 - 山里　敬也

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A new acquisition scheme of a DS/SS signal with transmit and receive antenna diversity 査読有り

Ikai Y., Katayama M., Yamazato T., Ogawa A.

IEEE International Conference on Communications 2 巻頁： 1256 - 1261 1999年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE International Conference on Communications

We propose the introduction of space diversity techniques to the code acquisition of a direct-sequence spread-spectrum signal. In this scheme, both a transmitter and a receiver have multiple antennas and the signals corresponding to all the combinations of the transmitter/receiver antennas are combined at the acquisition circuit of the receiver. The performance is evaluated for indoor packet radio communication systems from the viewpoints of average time for acquisition, probability of success of acquisition, and necessary preamble length. As the result, we show great performance improvements by the proposed scheme under slow and flat Rayleigh fading environment.

DOI： 10.1109/ICC.1999.765524

Scopus

A scheme for throughput improvement in voice/data CDMA packet communications 査読有り

Sandouk A., Yamazato T., Katayama M., Ogawa A.

IEEE Vehicular Technology Conference 50 巻 ( 1 ) 頁： 362 - 366 1999年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE Vehicular Technology Conference

In this paper, voice and data users with different bit rales are integrated in multi-code CDMA slotted ALOHA (MC-CDMA S-ALOHA) system. Performance measurement is obtained in the respect of throughput for data and outage probability for voice. Moreover, we consider the Modified Channel Load Sensing Protocol (MCLSP) as a traffic control to improve the throughput of data. We show that the MC-CDMA technique is an effective one to obtain a good throughput for data at an acceptable voice outage probability. We also show that the throughput of data can be improved with MCLSP. © 1999 IEEE.

DOI： 10.1109/VETECF.1999.797157

Scopus

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Adaptive array antennas for the base station of a multi processing gain CDMA system 査読有り

Morimoto A., Katayama M., Yamazato T., Ogawa A.

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E82-A 巻 ( 12 ) 頁： 2687 - 2695 1999年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences

This paper discusses the employment of adaptive array antennas at the base station of a Multi Processing Gain (MPG) CDMA system. It is shown that the adaptive array antenna with the weight control scheme based on the signal before despreading procedure does not increase but even decreases the performance than that with an omni-directional antenna, and the cause of this serious performance degradation is revealed. Then it is shown that the performance with the weight control scheme based on the signal after despreading procedure is always better than that with an omni-directional antenna. Furthermore, the possibilities of performance improvement by the combination of adaptive array antenna and interference cancellation-techniques are mentioned.

Scopus

An integrated voice/data CDMA packet communications with multi-code CDMA scheme 査読有り

Sandouk A., Yamazato T., Katayama M., Ogawa A.

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E82-A 巻 ( 10 ) 頁： 2105 - 2113 1999年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences

In this paper, we consider an integrated voice and data system over CDMA Slotted-ALOHA (CDMA S-ALOHA). We investigate its performance when multi-code CDMA (MC-CDMA) is applied as a multi-rate scheme to support users which require transmission with different bit rates. Two different classes of data users are transmitted together with voice. Performance measurement is obtained in respect of throughput for data and outage probability for voice. Moreover, we consider the Modified Channel Load Sensing Protocol (MCLSP) as a traffic control to improve the throughput of data. As a result, we show that the MC-CDMA technique is an effective one to obtain good throughput for data users at an acceptable voice outage probability. Furthermore, we show that with MCLSP, the throughput of data can be improved to reach a constant value even at a high offered load of data users.

Scopus

Chip-by-chip turbo coding for DS/SS systems 査読有り

Zheng C.

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E82-A 巻 ( 12 ) 頁： 2751 - 2756 1999年

Code acquisition of a DS/SS signal with transmit and receive antenna diversity 査読有り

Ikai Y.

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E82-A 巻 ( 12 ) 頁： 2728 - 2733 1999年

Performance of a LEOS communication system with overlaid and overlapped cell arrangement 査読有り

Ono K, Katayama M, Yamazato T, Ogawa A

MOBILE AND PERSONAL SATELLITE COMMUNICATIONS 3 頁： 131 - 145 1999年

Service fairness in CDMA cellular packet systems with site diversity reception 査読有り

Mori K.

IEICE Transactions on Communications E82-B 巻 ( 12 ) 頁： 1964 - 1972 1999年

Performance of a LEOS communication system with overlaid and overlapped cell arrangement 査読有り

K Ono, M Katayama, T Yamazato, A Ogawa

MOBILE AND PERSONAL SATELLITE COMMUNICATIONS 3 頁： 131 - 145 1999年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：SPRINGER-VERLAG LONDON LTD

The performance of a Low Earth-Orbital Satellite communication System with large overlap of neighboring cells and the layered cell structure is discussed. The rejection of a newly arrived call (call blocking) and the forced termination of a call which requests handover(call dropping) are used as the performance measures and simple one-dimensional model is introduced in order to analyze the performance. As the result, performance improvement by overlapping, overlaying, and the combination of them are shown. In addition, it is found that there are optimum parameters or combinations of them, which makes the performances best.

Web of Science

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Throughput improvement of a dual-class multi-code CDMA ALOHA system with modified channel load sensing protocol 査読有り

Sandouk A.

IEEE International Conference on Communications 2 巻頁： 1079 - 1083 1999年

Transmitter precoding with multiple transmit/receive antennas for high data rate communication in bandwidth-limited channels 査読有り

Ban K.

IEEE Vehicular Technology Conference 50 巻 ( 3 ) 頁： 1946 - 1950 1999年

CDMAによるマルチメディアパケット通信

山里敬也, 片山正昭, 小川明

電子情報通信学会技術研究報告 SST98 巻 ( 42 ) 頁： 39339 1998年12月

Hierarchical Transmission of Huffman Code Using Multi-Code/Multi-Rate DS/SS Modulation with appropriate Power Control 査読有り

A. Makido, T. Yamazato, M. Katayama, A. Ogawa

電子情報通信学会英文論文誌 E81-B 巻 ( 12 ) 頁： 2283-2289 1998年12月

Hierarchical transmission of Huffman code using multi-code/multi-rate DS/SS modulation with appropriate power control 査読有り

Makido S, Yamazato T, Katayama M, Ogawa A

IEICE TRANSACTIONS ON COMMUNICATIONS E81B 巻 ( 12 ) 頁： 2283 - 2289 1998年12月

Hierarchical transmission of Huffman code using multi-code/multi-rate DS/SS modulation with appropriate power control 査読有り

S Makido, T Yamazato, M Katayama, A Ogawa

IEICE TRANSACTIONS ON COMMUNICATIONS E81B 巻 ( 12 ) 頁： 2283 - 2289 1998年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

For transmission of video signals, it is important that the system allows a certain degree of flexibility in bit rate as well as quality, depending upon the requirements of media and channel conditions. In this paper, we discuss the hierarchical transmission of Huffman code using multi-code/multi-rate DS/SS system to realize flexible transmission. We first discuss and show that the structure of Huffman code tree directly expresses hierarchical structure, and that parallel transmission of Huffman code can achieve hierarchical transmission. By assigning different transmission data rate to the bits in each stratum, it is possible to transmit different amount of information from each stratum. Further, we show the quality of each of the stratum can easily controlled by an appropriate power distribution to each parallel transmission branch.

Web of Science

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伝送路の状態を考慮したマルチキャリア伝送用回線制御方式査読有り

柴田　伝幸，鈴木　徳祥，藤元　美俊，西川　訓利，山里　敬也，小川　明

電子情報通信学会論文誌 J81-B-I 巻 ( 11 ) 頁： 700-708 1998年11月

Initial acquisition of code timings and carrier frequencies of CDM down-link signals in multiple-LEO-satellite communication systems 査読有り

Ishizu M, Katayama M, Yamazato T, Ogawa A

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E81A 巻 ( 11 ) 頁： 2281 - 2290 1998年11月

Initial acquisition of code timings and carrier frequencies of CDM down-link signals in multiple-LEO-satellite communication systems 査読有り

M Ishizu, M Katayama, T Yamazato, A Ogawa

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E81A 巻 ( 11 ) 頁： 2281 - 2290 1998年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

In this paper, we discuss the initial acquisition of the code division multiplexed DS/SS down-link signals at a user terminal of multiple LEO mobile satellite communication systems. In LEO systems, a receiver generally receives signals from plural satellites for soft hand-off and for satellite diversity as a countermeasure to shadowing. In this situation, the signal from each satellite becomes the interference to the signals from other satellites. In addition to this inter-satellite interference, we have to consider the intra-satellite interference from user channels to a pilot channel because of the loss of orthogonality of channels at initial acquisition stage especially under frequency offsets due to Doppler effect. Thus in this paper, we analytically evaluate the performance of an initial acquisition scheme, taking the intra/inter-satellite interference under Doppler shift into account.

Web of Science

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New quasi-synchronous sequences for CDMA slotted ALOHA systems 査読有り

Saito M, Yamazato T, Katayama M, Ogawa A

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E81A 巻 ( 11 ) 頁： 2274 - 2280 1998年11月

New quasi-synchronous sequences for CDMA slotted ALOHA systems 査読有り

M. Saito, T. Yamazato, M. Katayama, A. Ogawa

IEICE Transactions on Fundamentals E81-A 巻 ( 11 ) 頁： 2274 - 2280 1998年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：電子情報通信学会

One of unique features of CDMA slotted ALOHA (CDMA S-ALOHA) is that user must synchronize his transmission to give slot. thus orthogonal sequence as spreading sequence would achieve ideal throughput if each of packets accomplish perfect synchronization. In ths presence of any ambiguity in synchronizations, however, quasi-synchronous (QS) sequences suit well with CDMA S-ALOHA system. In this paper, we introduce new QS-sequences obtained from the orthogonal Gold sequences and discuss their performance when applying to CDMA S-ALOHA systems. As a result, withstanding to access timing error, good performance is ensured with this sequence under the environment of AWGN, MAI (multiple access interference) and frequency non-selective fading, that is, micro or pico cellular systems and indoor wireless LANs.

CiNii Books

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