Abstract:

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.

Key words: Polar code, multi bit decoding, MSCL, segmented cyclical redundancy check, decoding delay, storage space