Basic Study towards a Multi-media Microcellular Personal Communication System

点击翻译按钮获取中文摘要

Basic research towards the next generation multi-media personal communications has been performed. Major research results during 1992-1993 are summarized below.1. Based on the theoretical analysis and computer simurations, optimum carrier to co-channel interference ratio (C/I) maximizing the packet transmission throughput per unit cell and also an optimum cluster size have been clarified for a broadband cellular system subjected to multiupath fading.2. A new dynamic channel allocation algorithm with transmitter power control is proposed. It tries to allocate a channel to which subsequent power control can be applied most effectively. By properly selecting the power control range, this alogorithm has been confirmed to realize very low transmitter power, without sacrificing other perfomance compared to conventional algorithms.3. A simulation system to evaluate the reconstructed picture quality of the highly compressed still image when transmitted over a multipath fading channel has been developed. An unequal error protection scheme, which assigns more parity check bits for error correction to the more important infomation, has been applied to the JPEG-like still picture transmission, and shown to be very effective to improve the picture quality when the total bit rate is fixed.4. An automatic repeat request (ARQ) error control protocol which utilizes the redundancy of the still picture itself has been proposed and shown to be very effctive to improve the picture quality when transmitted over a fading channel.5. As an optimum receiver for the mobile radio channel with large multipath delay and co-channel interference, we proposed an extended MLSE equalizer with an enhanced co-channel cancelling capability by trellis coded modulation, and confirmed its superior performance.