Trellis coding with multiple-symbol differential detection

Multiple-symbol differential detection (MSDD) of differentially encoded multiple phase shift keying (MPSK) uses maximum likelihood sequence detection of N symbols to achieve a performance gain over conventional 2 symbol differential detection. Using results from MSDD, an additive symbol-by-symbol metric is developed for noncoherent detection of trellis coded MPSK. In the additive white Gaussian noise (AWGN) channel, performance is the same as, and for some codes is better than, the performance of coherent detection of differentially encoded MPSK, while implementation complexity is basically the same as conventional 2 symbol differential detection. The decoder is shown to work well with a block interleaver in a Rician fading channel.