Low-complexity Successive Cancellation List Decoding for Polar Codes based on SPRT

Successive cancellation list (SCL) decoding algorithm for polar codes is one of the best decoding algorithms due to its excellent decoding performance. The decoding complexity of conventional SCL decoding algorithm is O(LN log N). The decoding complexity will increase as the size of the list increases. To solve this problem, we introduce an improved SCL decoding algorithm based on the sequential probability ratio test (SPRT). The proposed algorithm use double thresholds to decode the polar codes instead of single threshold decision used by the conventional SCL algorithm. Numerical results have shown that for (1024, 512) polar code, the proposed SPRT-SCL decoder can achieve a reduction in decoding complexity, and keep the similar decoding performance compared with conventional SCL decoder.