Joint Design Of Network Coding And LDPC Code

At present,the development speed of wireless communication rapidly,4G technology has been quite mature and has begun to move closer to the 5G people,the higher the communication network more and demand stimulates the development of wireless network technology to a higher level,but the wireless channel still exists the problem of multipath fading,no signal line will inevitably encounter some obstacles in interference in the process of transmission,so the signal will occur in the bypass in the process of decline,and the inevitable noise factors of channel interference,considering these conditions,the researchers found that in the process such as the bidirectional transceiver can be added into the relay this step,so it can be the original signal fading can be strengthened,and then forwarding get a stronger signal,but the traditional relay efficiency is relatively low,and only on the information storage and forwarding in the amplified signal The process will inevitably be the channel noise amplification and transmission slot cumbersome,so the network encoding is applied to the relay system is proposed,so that they can relay signals through certain denoising,and can reduce the error rate of the original signal encoding,improve the transmission rate,but the problem has not been transmission slot a good solution,therefore,in 2006,some professor at the Chinese University Hong Kong began to propose a physical layer network encoding,its basic principle is to join the network encoding the original physical layer,according to the superposition characteristic of electromagnetic wave,the thought will interfere with each other using the frequency of similar information skillfully to different conversion methods related mapping the domain into two information do not affect each other,thus solving the bottleneck problem of information can not be synchronized to send and receive.This paper first introduces the network encoding and physical layer network encoding the origin and development of the situation in recent years,and compared to three before the relay from the advantages and disadvantages,then joined the LDPC encoding based on physical layer network encoding,mainly on account of its excellent performance compared with some other codes,such as limit it can be close to the Shannon capacity at the same time,encoding complexity with respect to the Turbo code in simple and long code is better than Turbo code,the LDPC code redundancy in the code length is too long is less,can lead to poor performance when encoding,the code length is too short,it will lead to a longer redundancy,encoding efficiency,so this paper select the rate as the experiment object,1/2 LDPC code at the end of this paper,comparison of three kinds of joint encoding scheme,are combined with traditional encoding(TS),network(the direct encoding scheme Referred to as NC)and physical layer network encoding and LDPC code joint encoding scheme(PS),obtained by simulation of PS performance,1/3 higher than the NC encoding scheme efficiency,application of PS scheme,namely network encoding and LDPC encoding for joint design,can effectively improve the system throughput,transmission efficiency and increase channel capacity.