Optimization Of Polar Codes BP Decoding Algorithm And Design Of Cascade Codes

The proposal of polar codes is a milestone in channel encoding research.Due to polar codes' outstanding error-correction performance and low complexity of encoding and decoding characteristics,they have attracted extensive research and attention from both academia and industry circles,validating theirs important theoretical and application value.They have been adopted for the enhance mobile broadband(eMBB)control channel of fifth generation(5G)wireless communication standard already.The performance of the polar codes with finite length affects the wider application of the polar codes.In this paper,the error-correction performance of the polar codes with finite length is improved by optimization the belief propagation(BP)decoding algorithm of the polar codes and implementation the cascade of polar codes and LT codes.The main research contents and conclusions include:Firstly,the realization process of channel polarization,including channel combining and channel splitting,is summarized.On this basis,the encoding and decoding theories of polar codes are given,and the performance of polar codes is analyzed.Secondly,the advantages and disadvantages of several mainstream decoding algorithms for polar codes are analyzed and pointed out.Although the decoding delay of BP decoding algorithm is small,there are still some shortcomings.For the problem of high bit error rate in BP algorithm of polar codes,the list BP(Belief Propagation List,BPL)decoding algorithm based on CRC is proposed.The unnecessary iterative operation is reduced by CRC check.The simulation results show that the proposed algorithm improves the BP decoding performance of the polar codes.Finally,based on the research of polar codes and LT codes,the Polar-LT concatenated codes are proposed.The concatenated codes are serial concatenated codes based on polar codes.Optimized the error correction of fountain codes by BP joint iterative decoding.And the interleaver is inserted between the two codes to further reduce the bit error rate of decoding.The simulation experiments show that the effectiveness of the proposed cascaded codes.