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arXiv 2404.01136cs.ITmath.IT
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后验概率译码器下广义低密度奇偶校验码的密度进化分析

Density Evolution Analysis of Generalized Low-density Parity-check Codes under a Posteriori Probability Decoder

Dongxu Chang, Qingqing Peng, Zhiming Ma, Guanghui Wang, Dawei Yin

AI总结:

本文通过密度进化分析GLDPC码在APP译码器下的性能,改进高斯近似算法并引入消息不变子码,证明适当比例的GC节点可使GLDPC码显著优于LDPC码。

摘要:

本研究分析了广义低密度奇偶校验(GLDPC)码在后验概率(APP)译码器下的性能。我们探讨了GLDPC码在APP译码器下的集中性、对称性和单调性性质,将密度进化的适用范围扩展到GLDPC码。在二进制无记忆对称信道上,以BEC和BI-AWGN信道为例,我们证明在适当比例的广义约束(GC)节点下,GLDPC码相比其原始LDPC对应码能够缩小原本与信道容量之间的差距。此外,在BI-AWGN信道上,我们应用并改进了GLDPC码密度进化中的高斯近似算法。通过采用高斯混合分布来近似来自变量节点的消息分布,并采用高斯分布来近似来自约束节点的消息分布,可以在保持与高斯近似相似的低计算复杂度的同时,显著提高信道参数阈值的精度。进一步,我们识别出一类能够极大简化GLDPC码性能分析和实际译码的子码,我们称之为消息不变子码。利用上述技术,我们的仿真实验提供了经验证据,表明GLDPC码在使用APP译码器译码并配备适当比例的GC节点时,相比低密度奇偶校验(LDPC)码能够实现显著的性能提升。

英文摘要:

In this study, the performance of generalized low-density parity-check (GLDPC) codes under the a posteriori probability (APP) decoder is analyzed. We explore the concentration, symmetry, and monotonicity properties of GLDPC codes under the APP decoder, extending the applicability of density evolution to GLDPC codes. On the binary memoryless symmetric channels, using the BEC and BI-AWGN channels as two examples, we demonstrate that with an appropriate proportion of generalized constraint (GC) nodes, GLDPC codes can reduce the original gap to capacity compared to their original LDPC counterparts. Additionally, on the BI-AWGN channel, we apply and improve the Gaussian approximation algorithm in the density evolution of GLDPC codes. By adopting Gaussian mixture distributions to approximate the message distributions from variable nodes and Gaussian distributions for those from constraint nodes, the precision of the channel parameter threshold can be significantly enhanced while maintaining a low computational complexity similar to that of Gaussian approximations. Furthermore, we identify a class of subcodes that can greatly simplify the performance analysis and practical decoding of GLDPC codes, which we refer to as message-invariant subcodes. Using the aforementioned techniques, our simulation experiments provide empirical evidence that GLDPC codes, when decoded with the APP decoder and equipped with the right fraction of GC nodes, can achieve substantial performance improvements compared to low-density parity-check (LDPC) codes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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