Design of low-density parity-check (LDPC) codes for high order constellations

In this paper, we propose a simple design of LDPC codes which combines the good properties of multilevel coding (MLC) and bit-interleaved coded modulation (BICM) schemes with Gray-mapped PAM constellations and one-shot demodulation. Through simulations, we show that it performs better than MLC/parallel independent decoding for short-medium lengths, which is required for most applications, on AWGN and block-fading channels. Since 2/sup m/-PAM represents one quadrature component of 2/sup 2m/-QAM, the optimization holds true for QAM too. In general, this idea can be extended to other modulation schemes like 2/sup m/-PSK very easily.

[1]  Sae-Young Chung,et al.  Analysis of sum-product decoding of low-density parity-check codes using a Gaussian approximation , 2001, IEEE Trans. Inf. Theory.

[2]  A. Glavieux,et al.  Turbo-codes and high spectral efficiency modulation , 1994, Proceedings of ICC/SUPERCOMM'94 - 1994 International Conference on Communications.

[3]  Giuseppe Caire,et al.  Bit-Interleaved Coded Modulation , 2008, Found. Trends Commun. Inf. Theory.

[4]  Ravi Narayanaswami,et al.  Coded modulation with Low Density Parity Check codes , 2001 .

[5]  Daniel A. Spielman,et al.  Analysis of low density codes and improved designs using irregular graphs , 1998, STOC '98.

[6]  Rüdiger L. Urbanke,et al.  The capacity of low-density parity-check codes under message-passing decoding , 2001, IEEE Trans. Inf. Theory.

[7]  Niclas Wiberg,et al.  Codes and Decoding on General Graphs , 1996 .

[8]  Radford M. Neal,et al.  Near Shannon limit performance of low density parity check codes , 1996 .

[9]  Paul H. Siegel,et al.  Capacity-approaching bandwidth-efficient coded modulation schemes based on low-density parity-check codes , 2003, IEEE Trans. Inf. Theory.

[10]  Rüdiger L. Urbanke,et al.  Design of capacity-approaching irregular low-density parity-check codes , 2001, IEEE Trans. Inf. Theory.

[11]  Paul H. Siegel,et al.  Multilevel coding with low-density parity-check component codes , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[12]  Robert G. Gallager,et al.  Low-density parity-check codes , 1962, IRE Trans. Inf. Theory.

[13]  Robert F. H. Fischer,et al.  Multilevel codes: Theoretical concepts and practical design rules , 1999, IEEE Trans. Inf. Theory.