Performance of the concatenated coding system with a modified erasure declaration Viterbi decoder

Concatenated trellis coded 8PSK with Reed Solomon (RS) codes is studied over additive white Gaussian noise (AWGN) and Rayleigh fading channels. By using an erasure and error decoding scheme for a Reed Solomon decoder, one can get an improvement of bit error rate performances for the concatenated coding system. In order to realize this erasure and error decoding of RS codes, it is necessary to extract the reliability information with respect to the input symbols to the RS decoder. The reliability for an RS code is based on erasure declaration which can be obtained by an inner code decoder of a concatenated code. A new modified Viterbi decoder with averaged reliability information is proposed which is very suitable for a practical use with a truncated observed length. The bit error rate performance is calculated by computer simulation over AWGN and Rayleigh fading channel