On the performance of Trellis coded 8PSK with Reed Solomon codes
Date
1993
Authors
Harada, Yasuo
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Abstract
Concatenated Trellis coded 8PSK with Reed Solomon (RS) codes is studied over A WGN and Rayleigh fading channels.
Trellis coded modulation (TCM) achieves a high coding gain without any bandwidth expansion. The basic analysis of its performance is reviewed and confirmed by simulation using a truncated Viterbi decoder. Trellis coded 8PSK, which has an asymptotic coding gain of 3.6dB, can be further improved by concatenation with RS codes. By concatenating TCM with an RS code, the bandwidth of the overall system is expanded by the reciprocal of the coding rate of Reed Solomon codes. Improvement in the bit error rate performance is studied for this coding system with various combinations of RS codes.
A high rate code with R=0.9 and good bit error rate performance is chosen for further study for erasure and error decoding. Results suggest that we can improve the performance particularly at a low E,JN0, with sufficient reliability of decoded symbols. The reliability of the input symbols to the RS decoder is obtained by a modified Viterbi decoder. A modified Viterbi decoder is studied and the performance of the bit error rate is shown. In order to obtain an improvement in the performance, a new modified Viterbi decoder with averaged reliability information is proposed and the improvement in bit error rate is confirmed by computer simulation.