Adaptive channel decoding method for polar codes

Abstract

The polar code is a channel coding technology which can reach the Shannon limit in theory and has the advantage of low coding and decoding complexity. It is now one of the channel coding solutions in 5G communication. The successive cancellation list (SCL) decoding algorithm is the most commonly used decoding method for polar codes, but it has high memory and time complexity. Fast succesive cancellation (Fast-SC) decoding algorithm can effectively reduce the decoding complexity, but it has the problem of low reliability. In order to take into account the decoding efficiency and reliability of polar codes, a preFast-SCL decoding algorithm for adaptive channels is proposed. The algorithm combines the advantages of Fast-SC and SCL decoding algorithms. At the beginning of decoding, the Fast-SC algorithm is used to quickly obtain a group of decoding results and verify them. If the verification is passed, it will be outputed as the result, but if not, SCL decoding will be used to ensure the reliability. Simulation results show that the complexity of preFast-SCL decoding algorithm decreases gradually with the improvement of channel conditions. In additive white Gaussian noise channel, the reliability of preFast-SCL is basically the same as that of SCL decoding algorithm. When the signal to noise ratio (SNR) is 2.0 dB, the decoding complexity of preFast-SCL is reduced by 45% compared with SCL, and the time performance gain is better under the condition of higher SNR.