Multiple-symbols differential demodulation and decoding of CPM

In this paper a new technique which integrates digital demodulation of CPM signals and decoding of linear block codes is described. This technique is based on a maximum likelihood sequence estimation of the transmitted phase differences. Channel linear block codes are used to improve the performance of the multiple-symbols differential receiver. Upper and lower bounds on the bit error probability of the described detector in the case of AWGN channel are derived. Optimum linear block codes which minimizes the bit error probability at the output of the decoder are presented. Emphasis has been given to (7, 4) codes; in this case comparisons between the optimum code and other classical codes show that the proposed code is quite attractive.