Research On The Encoding And Decoding Algorithm Of Polar Code In 5G System

Currently,polar coding and decoding is a research hotspot in the fifth generation mobile communication system.In the encoding and decoding process,the bit channel reliability calculation method will affect the order of the bit channel reliability.Different order of the bit channel reliability will cause the transmission position of the information bit to be different.At the same time,when the reliability of the bit channel is constant,adding parity bits to assist decoding will change the bit error rate performance of the mobile communication system to a certain extent under the premise that the bit rate remains unchanged.This paper mainly studies the detailed process of channel polarization in polar coding,the decoding algorithm with higher performance when the bit rate is higher,and the analysis and verification of the proposed algorithm based on the 5G physical layer protocol simulation platform.The specific research is as follows:(1)Detailed derivation and analysis of the channel polarization process.Regarding the formulas appearing in the channel polarization,no detailed derivation is made,and the question of why this coding method should be used is not given.Starting from the most basic transition probability,this article derives the transition probability formula and the channel capacity formula of the whole process of the combined channel in detail.Then use formulas to calculate the channel capacity of each sub-channel,and finally,according to the size of the channel capacity,give the bit mixing mode.(2)An improved repetitive bit assisted decoding algorithm is studied.Due to repeated bits and cyclic redundancy check(CRC)bit assisted continuous cancellation list(RA-CA-SCL)decoding algorithm directly gives the length of the repeated bits,no specific analysis of the repeated bits In relation to the ratio of other check bits,this paper designs a check bit auxiliary decoding algorithm with the best proportion of repeated bits and CRC bits.The simulation shows that when the code rate of the polarization code is R=0.816,Quadrature Phase Shift Keying(QPSK)modulation is used.After the AWGN channel,the decoding performance of the improved decoding algorithm is further improved,and at the same time Under high signal-to-noise ratio,the complexity is almost the same as the comparison algorithm.(3)Build a 5G physical layer protocol link-level simulation platform that conforms to protocol standards.By using this platform,people can reproduce the key technologies of the physical layer of 5G mobile communications to a certain extent.At the same time,based on the platform,it is possible to verify the algorithms in the physical layer of the5 G communication system,and conduct in-depth research and improvement of the algorithms.Finally,the proposed improved decoding algorithm is applied to the platform,and related simulation analysis is performed.