| Research Abstract |
The aim of this study is to international cooperation between Japan and Europe in fields of adaptive array antennas and CDMA (Code Division Multiple Access) based on spread spectrum technique in order to provide extremely useful countermeasures to overcome a lack of frequency spectrum due to rapid increase of demands in wireless communications such as mobile communications. For instance, in a CDMA technique, (1) The way of leading the optimization criterion of the communication quality evaluation of the multimedia and modeling the wireless communication channel, (2) Proposal of a method of measuting traffic variance of multimedia CDMA wireless communication systems and a method of adaptive controlling the processing gain and transmission power for individual media, (3) Proposal of the signal processing in space and time domains based on adaptive digital filter and adaptive array antenna for rejection to narrow band interference and fading. Second, in a array antenna, (1) Modeling of time-varying multipath fading channel in space and time domains, (2) Analysis of improvement of frequency efficiency based on application of adaptive array antennas, (3) Proposal and analysis of space and time optimum equalizer, receiver, channel coding and decoding, (4) Proposal and evaluation of adaptive array antenna architectures and adaptive algorithms, (5) Application and performance analysis to CDMA environment.
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