Unit-memory codes for continuous phase modulation in an AWGN channel

The combination of unit-memory codes and continuous phase modulation in an additive white Gaussian noise channel is considered. Our motivation is based on the fact that when Rouanne and Costello's (1988) free distance lower bound is applied to unit-memory codes an improved lower bound is obtained. Specific constructions are considered for 4-level modulation schemes with full response and weak partial response-heuristic design rules are used for defining the subsets of codes within which an exhaustive search is conducted. The coding gains of the best codes within these subsets are better than those of best previously known multi-memory codes.<
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