Comparison of several receiver structures for trellis-coded GMSK signals: analytical and simulation results

The performance of some coherent receivers for trellis-coded GMSK signals is examined. It is shown that for the optimal Viterbi receiver in an AWGN channel the tightness of the analytical bounds on the bit-error probability obtained from an N-state error state diagram depends on the degree of non-uniformity of the scheme. The results of the computer simulations of a M-algorithm receiver and a two-stage receiver with separated demodulation and decoding are also given. It is demonstrated that using the M-algorithm the receiver complexity can be substantially reduced with only negligible performance degradation. It is also shown that the M-algorithm can successfully work in receivers for systems with interleaving/deinterleaving circuits