On Combining Chase-2 and Sum-Product Algorithms for LDPC Codes

ETRI Journal

关键词: sum-product (SP) algorithm;    Chase algorithm;    LDPC codes;   

Others  :  1186355
DOI  :  10.4218/etrij.12.0211.0510

【 摘 要 】

This letter investigates the combination of the Chase-2 and sum-product (SP) algorithms for low-density parity-check (LDPC) codes. A simple modification of the tanh rule for check node update is given, which incorporates test error patterns (TEPs) used in the Chase algorithm into SP decoding of LDPC codes. Moreover, a simple yet effective approach is proposed to construct TEPs for dealing with decoding failures with low-weight syndromes. Simulation results show that the proposed algorithm is effective in improving both the waterfall and error floor performance of LDPC codes.

   

【 参考文献 】

• [1]D. Chase, “Class of Algorithms for Decoding Block Codes with Channel Measurement Information,” IEEE Trans. Inf. Theory, vol. 18, Jan. 1972, pp. 170-182.
• [2]F.R. Kschischang, B.J. Frey, and H. Andrea Loeliger, “Factor Graphs and the Sum-Product Algorithm,” IEEE Trans. Inf. Theory, vol. 47, no. 2, Feb. 2001, pp. 498-519.
• [3]R.G. Gallager, Low-Density Parity-Check Codes, PhD dissertation, MIT, Cambridge, MA, USA, July 1963.
• [4]J. Hagenauer, E. Offer, and L. Papke, “Iterative Decoding of Binary Block and Convolutional Codes,” IEEE Trans. Inf. Theory, vol. 42, no. 3, Mar. 1996, pp. 429-445.
• [5]D. MacKay and M.S. Postol, “Weaknesses of Margulis and Ramanujan-Margulis Low-Density Parity-Check Codes,” Electron. Notes Theoretical Computer Sci., vol. 74, 2003.
• [6]T.J. Richardson, “Error Floors of LDPC Codes,” Proc. 41st Annual Allerton Conf. Commun., Control, Computing, Monticello, IL, USA, Sept. 2003, pp. 1426-1435.