Use of the M-algorithm to decode filtered CPM signals

The use of filters on coded modulation signals to yield new coded signals with better energy, and bandwidth performance, is demonstrated with continuous phase modulation (CPM) signals. The coding gain obtained is at the cost of a varying envelope. The M-algorithm can be used to efficiently decode filtered CPM signals at very low complexities. Free-distance comparisons show that for the schemes under consideration, the M-algorithm performance is practically that of maximum likelihood