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Abstract

Concatenated coding systems can offer good error performance over severely degraded channels. The combination of an inner trellis code and an outer Reed Solomon code has been a popular choice since it offers a good compromise between performance and complexity. In this thesis, a concatenated coded modulation scheme based on trellis coded modulation and a Reed Solomon code in the presence of Rayleigh fading is studied. The inner decoding process uses a soft output Viterbi algorithm which produces reliability information along with its output. This information is used to erase unreliable symbols in the decoded output. An errors-erasures Reed Solomon decoder is then used for the outer code. The block error probability performance gain achievable through the use of a soft output Viterbi algorithm in concatenated coding is studied using analysis and simulation. The effect of finite interleaving for the outer code is also considered.