极化码的多比特译码算法研究

针对极化码的连续消除列表（successive cancellation list，SCL）译码算法的高时延问题，提出了基于对数似然比的多比特SCL（multi-bit SCL，MSCL）译码算法，可以在一个判决时刻同时译出多个码字比特，在不损失译码性能的前提下，将译码时延由3N-2个时钟降为4N/M-2个时钟，相比于现有的多比特SCL译码算法，MSCL译码算法具有更低的路径度量值计算复杂度。为了降低循环冗余校验（cyclical redundancy check， CRC）辅助的SCL（CRC aided SCL，CA-SCL）译码算法的译码时延以及存储空间，提出了分段CRC辅助的MSCL（segmented CRC-aided MSCL，SCA-MSCL）译码算法，并提出了分段信息码字长度修正算法，来保证在信息位索引集A不变的前提下，实现每一分段结尾处对应的信息位索引能够被M整除。SCA-MSCL算法可以借助多个CRC判决来尽可能早地输出译码码字，从而减少译码器的存储空间以及译码时延。

Research on multi-bit decoding algorithms for polar codes

Aiming at the problem of high delay of successive cancellation lists (SCL) decoding algorithm for polar codes,a multi-bit SCL (MSCL) decoding algorithm based on log-likelihood ratio was proposed.The multiple codeword bits could be decoded simultaneously at a single decision time.Without loss of SCL decoding performance,the decoding delay was reduced from 3N-2 clocks to 4N/M-2 clocks.Compared with the existing multi-bit SCL decoding algorithm,the MSCL decoding algorithm had a lower complexity of the path metric calculation.In order to reduce the decoding delay and memory space of the cyclical redundancy check (CRC) assisted SCL (CA-SCL) decoding algorithm,a segmented CRC assisted MSCL (SCA-MSCL) decoding algorithm was proposed,and a segmentation information codeword length correction algorithm was proposed.By adjusting the length of the relevant segment,the information bit index set A was guaranteed.Under the same premise,the corresponding information bit index at the end of each segment could be divisible by M.The SCA-MSCL algorithm could output decoded code words as early as possible by using multiple CRC decisions,thereby reducing the decoder’s storage space and decoding delay.