Optimization of degree-profile matching interleavers for LDPC-coded modulation

Abstract

In this paper we introduce the concept of degree-profile matching interleavers (DPM-interleavers) and propose an LDPC-coded modulation scheme with a DPM-interleaver for 2(m)-PAM. One advantage of our scheme over conventional LDPC-coded modulation schemes is to support various modulation orders in a single coder/decoder by properly choosing DPM-interleavers according to each modulation order. Given the degree distribution for a good binary LDPC code, we present the optimized degree-profiles for DPM-interleavers by density evolution in the cases of 4-PAM and 8-PAM, respectively. Simulation results show that our proposed scheme provides compatible performance with those of conventional LDPC-coded modulation schemes.