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[Author] Akira FUKUDA(25hit)

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  • A Dynamic TDMA Wireless Integrated Voice/Data System with Data Steal into Voice (DSV) Technique

    Gang WU  Kaiji MUKUMOTO  Akira FUKUDA  Mitsuhiko MIZUNO  Kazumasa TAIRA  

     
    PAPER

      Vol:
    E78-B No:8
      Page(s):
    1125-1135

    This paper deals with the method of integration of voice and data in wireless communication systems. By applying the DSV (Data Steal into Voice) technique to D-TDMA (Dynamic Time Division Multiple Access) systems, this paper presents an MAC (Media Access Control) method of integration of voice and data for the systems such as cellular radios and cordless phones. After a brief review of the D-TDMA scheme and the DSV technique, the protocol called D-TDMA/DSV is described. Then, a static analysis to derive the channel capacity and a dynamic analysis to evaluate the throughput and delay performance are presented. An extension of TFA (Transient Fluid Approximation) analysis is employed in the dynamic analysis. With the same system parameters, the capacity of D-TDMA/DSV is compared with that of the traditional D-TDMA. Under the limitation of the blocking probability required for cellular radios, some numerical examples of dynamic analysis are given to show the throughput and delay performance of the system.

  • Software Receiver Technology and Its Applications

    Tokihiko YOKOI  Yoshimitsu IKI  Jun HORIKOSHI  Katsuji MIWA  Yoshio KARASAWA  Akira FUKUDA  Jun-ichi TAKADA  Yuichi KURODA  Takayasu SHIOKAWA  Yukitsuna FURUYA  Shigenari SUZUKI  Yasuhiro SENBA  Yoshihide YAMADA  Hiroshi HARADA  Yasuo SUZUKI  Kiyomichi ARAKI  

     
    PAPER

      Vol:
    E83-B No:6
      Page(s):
    1200-1209

    It is expected that software receivers will be widely available for radio communication, broadcasting and radio monitoring applications because they are able to be equipped with multimode, multirate and multiband functions in a single hardware platform. This paper describes the basic techniques required for software receivers for both hardware and software. The evaluation items and methods were studied and some evaluations done with an experimental software receiver model fabricated for radio monitoring applications. Future concepts in radio communication, broadcasting and radio monitoring applications where software receivers are thought to be suitable, were studied, and problems for realization identified.

  • An Integrated Voice and Data Transmission System with Idle Signal Multiple Access--Static Analysis--

    Gang WU  Kaiji MUKUMOTO  Akira FUKUDA  

     
    PAPER-Communication Systems and Transmission Equipment

      Vol:
    E76-B No:9
      Page(s):
    1186-1192

    Corresponding to the development of B-ISDN, integrated services for data, voice, etc. are imperatively required for the so called third generation wireless communication networks. In this paper, I-ISMA (Idle Signal Multiple Access for Integrated services) is proposed to transmit integrated voice and data traffic from dispersed terminals to a base station. In the system, data packets and the first packets of talkspurts of conversational speeches are transmitted using ISMA protocol over a shared channel while subsequent packets of talkspurts are sent with time reservation technique. The channel capacity of I-ISMA is evaluated and compared with that of PRMA. The region in which I-ISMA has larger capacity than PRMA is figured out. Generally speaking, I-ISMA has larger capacity than PRMA when the duration for transmitting and detecting an idle signal is not too long and the channel is not too congested by the reserved voice transmissions. When we concern real time voice transmission, delay is one of the most important performance measures. Only is a qualitative discussion on delay performance given here. The quantitative evaluation is obtained by the dynamic analysis in our succeeding paper.

  • On Multiserver Queues with m-Phase Synchronous Fluctuation of Traffic Intensity

    Walter SOTELO  Kaiji MUKUMOTO  Akira FUKUDA  

     
    PAPER-Systems and Control

      Vol:
    E70-E No:12
      Page(s):
    1187-1194

    The M(m)/M/K and M(m)/M/ models with synchronous fluctuation of traffic intensity are considered. The phase process is assumed to make changes according to an irreducible m-phase Markov chain. In contrast to the model with asynchronous fluctuation of parameters, phase changes may occur in synchronization with an arrival or beginning of a customer's service. We study mainly the steady-state regime of our models, and observe that, in general, closed form solutions for the limiting probabilities are difficult to obtain but their numerical computation is rather straightforward. We give a necessary and sufficient condition for the steady-state to be attained. For the model M(m)/M/K, it is shown that, for the case where the traffic intensity of one phase is greater than one (even if the average traffic intensity is less than one) the average queue length approaches infinity as the fluctuations among phases gets more sluggish. However, for the case where the traffic intensity for all phases is less than one, the queue length is moderate and not dependent as much on the rate of fluctuation among phases. Numerical examples are given and discussed. Finally, we point out that, our models may be more tractable than the asynchronous ones, when we try to generalize them to the case of general inter-arrival, service, or sojourn time distribution.

  • Meteor Burst Communications in Antarctica: Description of Experiments and First Results

    Akira FUKUDA  Kaiji MUKUMOTO  Yasuaki YOSHIHIRO  Kei NAKANO  Satoshi OHICHI  Masashi NAGASAWA  Hisao YAMAGISHI  Natsuo SATO  Akira KADOKURA  Huigen YANG  Mingwu YAO  Sen ZHANG  Guojing HE  Lijun JIN  

     
    PAPER-Terrestrial Radio Communications

      Vol:
    E87-B No:9
      Page(s):
    2767-2776

    In December 2001, the authors started two kinds of experiments on the meteor burst communication (MBC) in Antarctica to study the ability of MBC as a communication medium for data collection systems in that region. In the first experiment, a continuous tone signal is transmitted from Zhongshan Station. The signal received at Syowa Station (about 1,400 km apart) is recorded and analyzed. This experiment is aimed to study basic properties of the meteor burst channel in that high latitude region. On the other hand, the second experiment is designed to estimate data throughput of a commercial MBC system in that region. A remote station at Zhongshan Station tries to transfer data packets each consisting of 10 data words to the master station at Syowa Station. Data packets are generated with five minutes interval. In this paper, we explain the experiments, briefly examine the results of the first year (from April 2002 to March 2003), and put forward the plan for the experiments in the second and third year. From the data available thus far, we can see that 1) the sinusoidal daily variation in the meteor activity typical in middle and low latitude regions can not be clearly seen, 2) non-meteoric propagations frequently dominate the channel especially during night hours, 3) about 60% of the generated data packets are successfully transferred to the master station within two hours delay even though we are now operating the data transfer system only for five minutes in each ten minutes interval, etc.

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