关键词: 低密度奇偶校验码, 动态调度, 震荡现象, 贪婪特性, 相对残差

Abstract:

In order to solve the problems of the oscillation phenomenon and greedy characteristics in the dynamic scheduling decoding algorithm for low-density parity-check (LDPC) codes, the relative-residual-based dynamic schedule (RRB-BP) algorithm is proposed based on variable-to-check residual belief propagation (VC-RBP) algorithm. The variable nodes are grouped, then the relative residual value of the message passed by the variable nodes to the check node is taken as a reference, and the node with the largest relative residual value is updated in priority to accelerate the decoding convergence speed. For variable nodes oscillating in the decoding process, the posterior LLR (log likelihood ratio) message values before and after updating are processed with weighted average to improve the reliability of oscillating nodes. In the process of algorithm iteration, the relative residual value of messages transmitted from variable node to check node is attenuated to alleviate the greedy characteristic of decoding algorithm. The simulation results show that compared with the VC-RBP algorithm, the decoding performance gain of the proposed algorithm is 0.3~0.4 dB when the bit error rate is 10^-5, and the convergence speed is faster.

Key words: LDPC(low-density parity-check) code, dynamic scheduling, oscillation phenomenon, greedy characteristics, relative-residual