GF(q)域上LDPC码的改进扩展最小和译码算法

张仲明 许拔, Zhang Zhong-ming XU Ba

许拔, 张仲明, 何英亮 +1 more

通过分析扩展最小和算法（EMS）存在的问题，提出了一种针对q元LDPC码的改进译码算法．不同于EMS算法固定每次迭代中FHT的阶数，该算法根据每次迭代中变量节点的概率分布对的平均方差自适应选择FHT的阶数，并修改发生振荡的变量节点输出信息，使之同时包含上次迭代和当前迭代的信息，从而减少性能的损失与振荡的影响．仿真结果表明，在译码复杂度相当的情况下，该算法性能与收敛速度明显优于EMS算法．

黄晓非, 丁溯泉, 杨知行 +1 more

低密度校验码是一类能有效逼近香农限的好码，而高进制的LDPC码具有比二进制LDPC码更好的性能，但其译码复杂度太高不利于工程应用.本文提出了一种基于协同优化算法的低复杂度的高进制LDPC码的译码算法，并讨论了其在深空通信中的应用。

Xin Chen, Aidong Men

Low-density parity-check (LDPC) codes over finite fields GF(q) have a better performance than those of the binary low-density parity-check codes, at short and medium block lengths, but the decoder of GF(q)-LDPC has more complexity. In this paper, we present a new reduced-complexity belief propagation (BP) decoding algorithm for GF(q)-LDPC codes by analyzing the reliability of code symbols. Instead of update all the variable nodes during iteration, we just update variable nodes which are mostly to be in an error. The algorithm also shows a property to reduce the effects of oscillating on decoding. The simulations prove that we could improve performance and reduce complexity at the same time for short and medium GF(q)-LDPC codes.

李明 LI Ming, 徐胜智 XU Shengzhi, 陈慧敏 CHEN Huimin

Xin Chen, Aidong Men, Wei Zhou

Nonbinary low-density parity-check (LDPC) codes over finite fields GF(q) have a better performance than those of the binary low-density parity-check codes, at short and medium block lengths, but the decoder of GF(q)-LDPC has more complexity. In this paper, a new stopping criterion is proposed. Based on the changes of the variance of variable node¿s extrinsic information, the criterion can predict a decoding failure and decide whether the iteration of the decoder should be stopped. The simulation results show that the stopping criterion can greatly reduces the average number of required iterations of GF(q)-LDPC decoder with negligible performance loss.