Bit Metrics Based on SCLF Decoding Algorithm for Polar Codes

As an indispensable part of cyclic redundancy check aided Successive Cancellation List (CASCL) decoding and SCL bit flipping (CA-SCLF) decoding, sort operation increases the complexity of decoding. In order to minimize the quantity of sorting and simplify the complexity of SCLF decoding algorithm, this paper proposes an improved SCLF decoding algorithm, called NSCLF algorithm, which reduces the number of paths involved in sorting by detecting and pruning paths whose bit metric value is less than the set threshold before sorting operations. Meanwhile, pruning paths are dynamically selected according to node states during the flipping process. The flipping path selections are more accurate and the number of flipping correspondingly decreases. The simulation results demonstrate that when SNR is 3dB, the code length and code rate , while maintaining decoding performance comparable to that of traditional CA-SCLF, the sorting operation of our proposed NSCLF is about 93% less than that of traditional CA-SCLF, and the decoding complexity is less than that of traditional CA-SCLF.