An improved successive cancellation decoder for polar codes

Abstract

The successive cancellation decoder is the first decoding algorithm for polar codes which can achieve binary memoryless symmetric channels' capacity. However, SC does not perform well. A method called SC List algorithm is proposed and is one of the best algorithms in terms of balance between bits error rate and computation complexity. In this paper, we find that CRC-aided SCL algorithm improves the effect of polar codes. This scheme is that CRC and polar codes play an inner and outer codes role in a concatenation codes. Simulation shows that Frame error rate of length N=1024 under SCL decoding with L=2 and an 8 bit CRC polar codes perform better than length N=1944 under offset min-sum decoding LDPC codes with a flooding schedule and a maximum of 10 iterations. All simulation is in the binary input addition white Gaussian noise channel and use BPSK modulation. Furthermore, the complexity of CRC-aided SCL algorithm is acceptable. The only weak point is that we need to sacrifice a little information rate.