Research On Encoding And Decoding Algorithm Of The Multi-Kernel Polar Codes

In recent years,polar codes have become one of the research hotspots in channel coding,which have been adopted as a coding scheme for the Enhanced Mobile Broadband(eMBB)scenario of the 5G control channel.However,most of the research of polar codes is based on the code length N=2",but more flexible code lengths are required in practical applications.Polar codes constructed by higher dimensional kernel than 2-kernel usually achieves better performance.Cascading a high-dimensional kernel with 2-kernel to construct a multi-kernel polar codes can achieve a more flexible code length.In this thesis,the construction method of multi-kernel polar codes to realize arbitrary code length is studied.And we propose the CA-PSCL(CA-Permuted SCL)algorithm for multi-kernel polar codes to improve the CA-SCL(CRC Aided Successive Cancellation List)algorithm.The main work is as follows:1?In order to realize the polar codes of arbitrary code length,this thesis proposes a puncturing algorithm based on multi-kernel polar codes.The mother codes that are closer to the length of subcodes are constructed by different kernels.And the proposed puncturing algorithm is executed to reduce the number of punctured bits.Compared with the puncturing algorithm based on 2-kernel polar codes,the performance of the proposed algorithm is better.By analyzing the transfer of multi-kernel polar codes channel capacity and the upper bound of SC decoding error probability in each puncturing scheme,the puncturing scheme is obtained.The distance spectrum of the generator matrix after puncturing is calculated,and the location information of the polar codes is reselected by the greedy algorithm to obtain better performance under the finite code length.For the subcodes(191,96),compared with the puncturing algorithm based on the mother codes(256,96),the performance of proposed algorithm has a gain of 0.55 dB under SCL(L=8)decoding at Block Error Rate(BLER)of 10-4,and the number of the punctured bits is reduced by 64.2?In order to improve the decoding performance of multi-kernel polar codes,an improved CA-PSCL decoding algorithm is proposed.The same encoding result is obtained by permuting any two stages of the encoding structure using 2-kernel.Both of encoding and decoding structure are permuted simultaneously,the order of the polarized subchannels is changed.In the decoder,which is matching permuting encoder,the highly reliable polarized subchannels successfully decoded earlier.It improves the reliability of late bits decoding.By adjusting the order of the log likelihood ratio at the receiving side,the structure of the decoder is unchanged,and mapping permuting structure of encoder.The results show that the CA-PSCL(L=8)algorithm can provide over 0.25dB gain at BLER=10-4 with the(192,96)polar code.