A Stopping Criterion Based on Check-Sum Variations for Decoding Nonbinary LDPC Codes

摘要

Low-density parity-check (LDPC) codes have very good performance when they are decoded by iterative belief-propagation (BP) decoding algorithms and are widely used in many applications. However, the iterative decoding of LDPC codes has a huge complexity, especially for LDPC codes constructed over the nonbinary field GF(q). Traditionally, the iterative process is performed until the maximum number of iterations is reached or a codeword is found, which is unnecessary for undecodable code blocks. Hence, it is important to develop certain stopping criterion to identify these undecodable blocks and terminate the decoding process in advance. Based on the analysis of check-sum variations in the decoding process, a stopping criterion is proposed in this paper. Simulation results indicate the proposed criterion can greatly reduce the average number of iterations (ANI) over a wide range of signal-to-noise ratio (SNR) values, with little performance degradation compared with the traditional BP decoding.