Polar code fast serial cancellation list decoding algorithm based on bit flipping

Abstract

The invention discloses a polar code fast serial cancellation list decoding algorithm based on bit flipping. According to the algorithm, the decoding rate is increased by adding identification of fourspecial nodes; meanwhile, a critical set is constructed, error propagation caused by previous decoding errors is avoided; a turnover position is judged and determined by respectively calculating loglikelihood ratio (LLR) values of two special nodes, namely an information bit R1 node and a single parity check (SPC) node; when the parity check bit does not meet the requirement, only the information bit corresponding to the most unreliable input LLR needs to be overturned, so that the overturning frequency is reduced, and the complexity is reduced. Simulation results show that when the block error rate is 10 <-5 >, the signal-to-noise ratio of the improved fast SCL decoding algorithm based on bit flipping is improved by 0.09 dB compared with that of an original SCL decoding algorithm basedon bit flipping, so that the improved decoding algorithm provides a reference algorithm under the condition of medium and short code lengths.

Description

technical field [0001] The invention belongs to the field of signal processing and relates to a decoding algorithm of polar codes in channel decoding. This method is mainly based on bit flipping and special node identification to improve the decoding algorithm of the Serial Cancellation List (SCL). Background technique [0002] Polar code is a new type of coding method, which was first proposed by Professor Arikan of Bilkent University in Turkey in 2008. It is also the first channel coding method that has been proven to reach the Shannon limit. Therefore, polar code is particularly important in the field of coding and decoding technology. is attractive. On November 17, 2016, during the discussion of the 87th short code meeting of the 3rd Generation Partnership Project (3GPP) RANI in the United States, the polar code mainly promoted by China's Huawei was adopted as the short code in the 5G control channel. code scheme. [0003] The research of polar codes mainly focuses on...

AI Technical Summary

Problems solved by technology

Professor Arikan proposed a basic serial cancellation (Successive Cancellation, SC) decoding algorithm when he proposed the polar code, but the performance of the SC algorithm is not good when the code length is short and medium, and the performance is not as good as that of Turbo code and SC. Low Density Parity Check (Low Density ParityCheck, LDPC) code, so Tal and Vardy proposed the SCL algorithm, which improved the decoding performance by increasing the path list size L to retain multiple decoding results, but then What comes is the increase in complexity, which is not easy to implement in hardware design

Because the algorithm has path duplication and path deletion, it will lead to the calculation, sorting, and selection of a large number of PM values. The process is complicated and time-consuming, and cannot meet the purpose of high efficiency.

[0004] The present invention proposes a bit-flip-based polar code fast SCL decoding algorithm for the problem that the bit-flip-based SCL decoding algorithm cannot take into account both decoding performance and decoding complexity.

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