Joint Design Of Polar Code And Physical Layer Network Coding For Two-way Relay Communication

In recent years,with the rapid development of wireless communication,people have higher and higher requirements for data services.The larger data volume and faster transmission speed have put forward higher requirements for wireless communication technology.However,the completely open characteristics of wireless channels and the problems of fading and coverage make the transmission of data require relay assistance in many cases,and the idea of cooperative communication arises.The proposed network coding effectively improves the throughput of the network,and because of the broadcast characteristics and superimposition characteristics of the wireless channel itself,the network coding at the physical layer and combined with a certain channel coding technology can obtain more than the traditional relay system.Good performance.Polar code is currently the only channel coding method that can reach Shannon's limit.The complexity of the coding and decoding algorithm is low and the delay is small.Therefore,this paper proposes a joint design scheme of physical layer network coding and Polar code.The details are as follows:First,the concept and system model of two-way relay communication,the basic principles,advantages and disadvantages of network coding are introduced,and then the three information transmission modes and implementation processes in the wireless relay channel are explained in detail.The performance of these three transmission modes is analyzed and compared.It can be seen that the physical layer network coding can improve the transmission efficiency and throughput of the network compared with the traditional transmission mode and direct network coding mode,and is verified by simulation analysis.Then the relay decoding scheme jointly designed by physical layer network coding and channel coding is derived.The discovery of the LDPC code proves that it is an excellent channel coding method.The Gaussian elimination coding method used in this paper and the BP decoding algorithm based on the confidence propagation algorithm are explained,the complexity of the compiled code is analyzed,and a single shot is performed.Simulation of the error rate of LDPC codes with different code lengths in the case of single reception.After that,the scheme of joint design of LDPC codes and physical layer network coding was proposed,and the effect of different code lengths on the BER performance of the joint system was analyzed by simulation.Polar code is a channel coding method with excellent performance and proven to reach Shannon's limit.The channel coding method in the joint system we finally studied is Polar code.This article introduces the coding principle of the Polar code and the continuous elimination decoding(SC)and continuous elimination list decoding algorithm(SCL)used in this article.By simulating the Polar code with different code lengths and decoding methods in the case of single transmission and single reception The bit error rate of transmission verifies the performance of Polar codes.Then introduces the traditional Polar code and network coding combination scheme,analyzes the deficiencies,on this basis,puts forward the Polar code and physical layer network coding joint design scheme.Finally,the performance of the joint design system in terms of bit error rate and throughput is analyzed through simulation.The simulation results show that both the code length and the decoding algorithm will affect the reliability of the joint system,and the scheme of the joint coding system proposed in this paper actually improves the network throughput compared with the direct network coding system,and also ensures the reliability of the system as much as possible.On the other hand,the joint design system that selects LDPC codes relative to the channel coding method can reduce the complexity and calculation of decoding without losing the system reliability as much as possible,which verifies the feasibility and effectiveness of the scheme in this paper.