Research on concatenated trellis-coded modulation system combined with space-time coding over frequency selective fading channel

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1.Transmission DiversityThe transmit diversity system proposed by Lindskog, which is an extension of the diversity system proposed by Alamouti, has been extended for frequency selective fading channel. This research has studied combinations of the Lindskog system with parallel or serial concatenated trellis-coded modulation.Though the Lindskog system can separate signals from two transmit antennas, inter-symbol interference remains for frequency selective fading channel. When higher transmission speed is necessary, the inter-symbol interference happens over more symbols. Decision aided equalization has been adopted as it require practical amount of signal processing task even for such circumstance. Computer simulation results has shown that the system combined with parallel concatenated trellis-coded modulation realizes 6dB diversity gain by using two transmit antenna and 3.5dB coding gain at the bit error rate (BER)10^<-2>. It has also shown that the system combined with serial concatenated trellis-coded modulation realizes 4.5dB diversity gain and 10.5dB coding gain at BER=10^<-4>.2.Hardware design of concatenated trellis-coded modulationIn 2003, a hardware decoder for the concatenated trellis-coded modulation has been designed for 8-PSK modulation.In 2004 a hardware decoder which can be adopted for higher order modulation and requires less amount of signal processing task has been proposed and implemented on a field programmable gate array (FPGA).3.Optimization of codingOptimum code has been searched under the assumption of many diversity paths by using theoretically derived upper bounds of BER.