Optimization of LDPC Codes by Extrinsic Information Transfer Chart

Abstract:

The optimization of degree profiles of low-density parity-check (LDPC) code in additive white Gaussian noise (AWGN) multiple access channel (MAC) by fitting the transfer characteristics of variable nodes detector (VND) and that of check nodes detector (CND) is discussed. Extrinsic information transfer (EXIT) characteristics are used for determining the degree profiles based on curve fitting. The convergence the optimized LDPC code is ensured by the EXIT characteristics of VND and CND. Degree profiles are obtained and check matrix is constructed. Simulation results show that the method is variable in designing LDPC code degree profiles in MAC with reduced complexity compared with density evolution based on Gaussian approximation.

• Periodical: Applied Mechanics and Materials (Volumes 427-429)
• Pages: 1518-1523
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.427-429.1518
• Online since: September 2013
• Authors: Jing Xi Zhang
• Keywords: Additive White Gaussian Noise (AWGN), Degree Profile, Extrinsic Information Transfer (EXIT), Low Density Parity Check (LDPC) Codes, Multiple Access Channel (MAC)

References

[1] T. J. Richardson and R. Urbanke, The capacity of low-density paritycheck codes under message-passing decoding, IEEE Trans. Inform. Theory, vol. 47, p.599–618, Feb. (2001).

DOI: 10.1109/18.910577

[2] S.Y. Chung, T.J. Richardson, and R.L. Urbanke. Analysis of sum-product decoding of low-density parity-check codes using a Gaussian approximation, IEEE Trans. Inform. Theory, vol. 47, no. 2 , p.657 – 670, Feb. (2001).

DOI: 10.1109/18.910580

[3] S. ten Brink, Convergence behavior of iteratively decoded parallel concatenated codes, IEEE Trans. Commun., vol. 49, p.1727–1737, Oct. (2001).

DOI: 10.1109/26.957394

[4] S. ten Brink, G. Kramer, A. Ashikhmin. Design of low-density parity check codes for modulation and detection. IEEE Transactions on Communications, vol. 52, pp.670-678, April (2004).

DOI: 10.1109/tcomm.2004.826370

[5] J. Zhang and Z. Bie, Enhancing the performance of IDMA system by irregular LDPC codes, IET ICWMMN Proceedings. Beijing, China, Sep. (2010).

DOI: 10.1049/cp.2010.0631

[6] D. Guo and S. Verd´u, Randomly spread CDMA: Asymptotics via statistical physics, IEEE Trans. Inform. Theory, vol. 51, p.1982–2010, June (2005).

DOI: 10.1109/tit.2005.847700