无线信道下基于可译集的喷泉码增量译码算法

针对无线信道中数字喷泉码BP译码算法复杂度高、增量译码效率低下的问题，提出了一种基于可译集的增量译码算法。该算法给出变量节点成功译码时似然比所需达到的合适门限值Tre的理论分析方法，将译码过程中似然比高于门限值的变量节点归入可译集，提前译出以减少计算量；另一方面，若译码失败，增加开销重新译码时可先利用已成功译出的部分变量节点简化Tanner图，只对未达到译码门限的变量节点进行迭代，进一步减少计算量，并给出了算法描述和复杂度分析。最后通过仿真表明，该算法与传统的BP译码算法性能相同，但计算量大大减少，效率显著提高。

Delta Decoding Algorithm of Fountain Codes Based on Ripple Set on Wireless Channels

To improve the performance of BP decoding algorithm of digital fountain codes on wireless channels, a delta decoding algorithm based on the ripple set is proposed. The algorithm analyzes the likelihood ratio threshold of the variable nodes. When the likelihood ratio of the variable node is greater than the threshold, it can be successfully decoded in advance. On the other hand, when the overhead is increased, we can delete those variable nodes that have been decoded, and decode the nodes that have not achieved the decoding threshold, to further reduce the amount of calculation. The simulation shows that the performance of the new algorithm is as good as the traditional BP decoding algorithm, but the decoding efficiency is greatly improved.