Belief propagation(BP) decoder is a low decoding latency algorithm for polar codes. However,the block error rate(BLER) performance of the BP decoder is inferior to the cyclic redundancy check(CRC)aided successive cancellation list(CA-SCL) decoder with medium list size for polar codes. Thus, in this paper, we introduce a bit-flip method into the belief propagation list(BPL) decoder and propose a BPL bitflip(BPLF) decoder to improve the BLER performance of BP-based decoder for polar codes. The proposed decoder is based on a CRC-aided belief propagation list(CA-BPL) decoder, and the error-prone bits are obtained from the decoded result to construct flip bits set(FBS). The bits in FBS are flipped to obtain the correct decoding result. Moreover, the simulation results show that the BLER of the proposed BPLF decoder is significantly superior to that of the CA-BPL despite having the same list size, e.g., there is 0.75 dB gain at BLER = 10.4 with list size 64. Furthermore, the decoding complexity and latency of the proposed BPLF decoder are only slightly higher than those of CA-BPL decoder with the same list size in medium to high signal-to-noise ratio(SNR) region.
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