Research On Improved SC Decoding Algorithm Of Polar Codes In EMBB Surroundings

Polar Codes are the first forward error correction codes that were theoretically proved to achieve the channel capacity based on the phenomenon of channel polarization.Ploar codes have simple rate matching,theoretically proven no error floor,excellent error correction performance,low encoding and decoding complexity and other advantages were selected as the coding scheme for the control channel in the 5G enhanced mobile broadband(e MBB).The thesis aims to improve the shortcomings of existing polar codes decoding algorithm,which has important theoretical significance and reference value,and its main work content is roughly summarized as follows:1.Firstly,comprehensively analyze the channel combining and channel splitting processes based on the channel polarization phenomenon,and verify the channel polarization phenomenon through simulation experiments;secondly,the construction method of the polar codes are studied which based on the selection of information bits and the formation of the generator matrix,and various construction methods are verified by simulation experiments;finally,based on several classic decoding algorithms,the polar codes decoding process and principles are discussed,and the simulation performance is compared and analyzed.2.Aiming at the problem of high decoding complexity in the existing quantization-based successive cancellation decoding algorithm,a uniform quantization-based fast simplified SC(UQ-Fast-SSC)decoding algorithm is proposed.The core idea of the algorithm is to reduce the computational complexity and storage complexity of the SC decoding algorithm by adding special nodes recognition algorithm and uniformly quantizing the input of the SC decoder.The simulation analysis of the experimental results shows that when the bit error rate is 10^-6,the decoding performance of the proposed algorithm and the original SC algorithm based on quantization differs by 0.10d B.However,the UQ-Fast-SSC decoding algorithm reduces the computational complexity about 46.29%compared with the other two algorithms,and reduces the storage space of the SC decoder,which is more friendly to the hardware implementation of the SC decoder.3.Aiming at the problem of decoding performance loss in the SC decoding algorithm based on the min-sum algorithm,a polyline approximation algorithm based on the least mean square error is proposed.The core idea of the polyline approximation algorithm is:approximate fitting sum-product algorithm based on the least mean square error algorithm,so as to reduce the decoding performance loss due to approximation while ensuring that the computational complexity of the SC decoding algorithm is reduced.The simulation results show that:when the bit error rate is 10^-6,the net coding gain of the proposed improved algorithm is 0.18 d B compared to the SC decoding algorithm based on the min-sum algorithm.