基于关键翻转集合的极化码Fast-SSC-Flip译码算法

为了降低极化码快速简化串行抵消翻转(Fast-SSC-Flip)译码算法的候选翻转比特集合大小，减小搜索复杂度，该文提出一种基于关键翻转集合的极化码Fast-SSC-Flip译码算法。基于快速简化串行抵消(Fast-SSC)译码过程中首位译码错误信息比特有极大的概率落于关键集合(CS)中，以及Fast-SSC-Flip译码算法的候选比特均为码字比特，所提算法利用极化码的生成矩阵得到与CS中信息比特相应的码字比特，并用这些码字比特构建关键翻转集合(CFS)作为候选翻转比特集合。实验结果表明，在使用相同候选比特可靠性度量准则的前提下，在码长$N = 1;024$及码率$R = 0.5$时，该文所提基于关键翻转集合的Fast-SSC-Flip译码算法相较于传统Fast-SSC-Flip算法在不损失译码性能的情况下，候选翻转集合大小显著降低；相较于新的快速简化串行抵消翻转(N-Fast-SSC-Flip)算法有相近的译码性能，但候选翻转集合至少缩小了77.93%。

Fast-SSC-Flip Decoding Algorithm Based on Critical Flip Set for Polar Code

In order to reduce the candidate flip bit set size when using Fast Simplified Successive Cancellation Flip(Fast-SSC-Flip) decoding algorithm and decrease the search complexity, a kind of Fast-SSC-Flip decoding algorithm based on critical flip set for polar code is proposed. Based on the fact that the first decoding error information bit in the Fast Simplified Successive Cancellation (Fast-SSC) decoding process is highly likely to fall into the Critical Set (CS), and the candidate bits in the Fast-SSC-Flip decoding algorithm are all codeword bits, the proposed algorithm uses the polar code generator matrix to obtain the corresponding codeword bits of the information bits in the CS, and constructs a Critical Flip Set (CFS) as the candidate flip bit set. Experimental results show that, under the same candidate bit reliability measurement criteria, when the code length N = 1 024 and the code rate R = 0.5, the proposed Fast-SSC-Flip decoding algorithm based on critical flip set reduces significantly the candidate flip bit set size without sacrificing decoding performance compared to the traditional Fast-SSC-Flip algorithm; Compared to the New Fast Simplified Successive Cancellation Flip( N-Fast-SSC-Flip) algorithm, the candidate flip bit set decreased by at least 77.93% while maintaining similar decoding performance.