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In this letter we consider serially concatenated continuous phase modulation (SCCPM) schemes with symbolwise interleaving and an additional intra-symbol interleaving. We use extrinsic information transfer (EXIT) chart to optimize the outer code and intra-symbol interleaver. We show that, for various continuous phase modulation (CPM) parameters, the outer code with memory 2 may not always be the best choice. For CPM with modulation index ℎ = 1/2, considerable improvements can be achieved by moderately increasing the outer code memory.

In this paper we consider a class of fully-sourceinvolved low-density parity-check (FSI-LDPC) codes. We show that the code designed based on the conventional bipartite graph may not be feasible or implementable. We investigate the applicability of the bipartite graph as a representation of an FSI-LDPC code for density evolution. We discuss the applicable range of the bipartite representation. Then we introduce tripartite graph for FSI-LDPC codes as a modification of the conventional bipartite representation. In this graph, we consider the degree distributions for source nodes and redundancy nodes separately. For design of FSI-LDPC codes, we show that, when code rate is low, possible performance degradation originated from the conventional bipartite representation can be prevented by adopting the tripartite representation. 1125 1-4244-0977-2/07/$25.00 c 2007 IEEE

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