Joint Design And Decoding Optimization Of Network Code And LDPC Code

Nowadays,with the rapid development of science and technology,wireless communication has become an effective way for people to contact each other,and a large amount of data and high-speed transmission have put forward higher requirements for wireless communication.However,wireless communication has the limits of fading and propagation distance,so our communication needs to use relay collaboration.R.Ahlswede introduced the concept of network coding in wireless communications.The introduction of this concept led to the addition of data processing to the relay,which fundamentally improved the problem of slow data transmission.Later,based on network coding,Zhang and other researchers from the Chinese University of Hong Kong further proposed the application of network coding to physical layer network coding.This technology has realized the superposition and use of wireless channels,and also improved the network transmission efficiency.This paper first introduces the history of network coding,and briefly analyzes its development status,then lists the traditional communication modes and makes a comparative explanation.In this paper,three modes of two-way cooperative communication are given.Among the three modes of cooperative communication,we compare the three modes and describe the transmission process in detail through the structure diagram.This paper introduces the LDPC code,which is a low-density parity code,which is a kind of channel code with excellent performance and a kind of error correction code that can approximate the limited capacity limit.In this paper,the algorithm steps and methods of coding and decoding are given.This paper focuses on the joint design of network coding and LDPC code,improves the communication efficiency of the system by using the strong error correction performance of LDPC code,and gives a scheme for the joint design of network coding and LDPC code.The design process and general analysis of the scheme are given in detail.Then the scheme of decoding optimization of network coding system is given,and the effect of decoding optimization is discussed by changing its factor condition bysimulation.Data quantity,number of code blocks,number of iterations and signal-to-noise ratio are several important factors of simulation.This paper first discusses the effect of single factor conditions on decoding effect and time,and we not only require the accuracy of the BER to be as accurate as possible,but also ensure that the time can not be too long.Therefore,we require that the simulation time code rate be as small as possible,and the generating matrix G can not be too small,so as to ensure that the accuracy of the BER is as high as possible.At the same time,in order to ensure a short time,just the right number of iterations should be selected,which is generally 7-8 times.The number of simulation code blocks must be appropriately reduced to ensure that the amount of operation is minimized and the time loss is reduced.Next,the joint design system of physical layer network coding and LDPC code is fully analyzed.Then the optimization design method is proposed.Finally,it is compared with the physical layer network coding system.Through simulation,it is found that it has the same decoding optimization effect as the network coding system.