规则低密度校验码的比特翻转解码算法研究

A Two-stage Bit-flipping Decoding Algorithm for Regular LDPC Codes

本文提出一种规则低密度校验码的比特翻转迭代解码算法。在解码算法的每一次迭代运算过程中,解码运算可以从总体上分为两个阶段:首先,满足可靠性要求的校验节点从与其相邻接的信息节点中选择一个信息比特作为翻转候选比特;然后,解码算法采用投票的方法对于这些候选翻转比特进行进一步的筛选。本算法由于对于最终翻转比特的选择结果是通过两次筛选而得到的,从而极大地降低了误翻的概率,加快了迭代解码算法的收敛速度,提高了系统的性能。另外,在第一阶段的比特选择过程中,我们综合校验节点所提供的校验检测信息和信道输出所提供的可靠性信息,提出了新的翻转比特选择标准。仿真结果表明,本文所提出的解码算法有着较好的性能,在解码运算复杂度和纠错性能之间提供了另外一个均衡。

A two-stage bit-flipping decoding algorithm for regular low-density parity-check（LDPC） codes is proposed in this paper. In the first stage, the decoding process is carried on check nodes. Every reliable check node selects one bitflipping candidate from its neighbor variable nodes. And on the second stage, the decoder refines the selections from the first stage using maximum votes queue algorithm. Since the ultimate flipping bits are got through two selections, the probability of doing wrong flipping is greatly reduced. Therefore, the convergence of the decoding algorithm becomes faster and the performance of the system is improved. Moreover, a new bit-selection criterion which incorporates the syndrome and the absolute value of the log-llkelihood ratio of the bit vector is proposed during the first stage of decoding. Simulation results show that our proposed decoding algorithm provides another kind of good tradeoff between error-correcting performance and decoding complexity.