The combination of unit-memory codes and continuous phase modulation in au additive white Gaussian noise channel is considered. Our motivation is based on the fact that when Rouanne and Costello's  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.
|Number of pages||8|
|Journal||IEEE Transactions on Communications|
|State||Published - 1995|
Bibliographical noteFunding Information:
Paper approved by Dariush Divsalar, t,he Editor for Coding Theory and Applications of the IEEE Conmmuicatiorrs Society. Manuscript received February 1, 1992; revised December 9, 1992. This work is dedicated t,o Aniiram H. I<aspi (1948-1990). This work was supported by the NSF Engineering Research Cent,ers Program, CDH-8803012. The aut.hor was with tlie Department of Electrical Engineering and the Instit,ute for Systems Research. Universit,y of Maryland, College Park, MD 20712. He is now with Orckit Conim~u~icationLst d., Tel-Aviv 67418, ISRAEL. IEEE Log Number 9410058.