Trellis coded modulation with multiple symbol differential detection

The use of the multiple-symbol differential detection technique in trellis coded differential M-ary phase shift keying modulation schemes (MSDD-TCM) over correlated flat Rayleigh fading channels is demonstrated. This technique uses multiple symbols to exploit the statistics of the fading channels to improve the error performance of the system without sacrificing the advantage of the time diversity attribute of the trellis coded modulation (TCM) schemes. Optimal metrics are obtained for the Viterbi decoder. By means of a closed form analytical expression and computer simulations based on simplified sub-optimal metrics for bit error rate performance, it is shown that the MSDD-TCM technique is able to suppress the irreducible error floor associated with conventional differential trellis coded modulation