The Research Of Random Network Coding And Precoding For Complex Field Network Coding

Network coding,as a momentous achievement of information technology in the21 st century,has been improved in great speed in recent years.Research results shows that network coding can improve througput,reliability and robusty for wireless network by allowing executing the encoding and decoding operation at the network nodes.However,these operations will increase the computation complexity and thus bring overhead to the network.Moreover,it's still an enormous challenge to deal with the interference of signals which from multiple source nodes.Therefore,the study of new and more optimal transmission strategies of network coding becomes a key issue for it's practical application.This paper briefly analyses the background and significance of network coding at home and abroad,concludes the development process of network coding and introduces mathematical model of network and the fundamentals of network coding.At the basis of reading a lot of literatures and analyzing the network coding theory,two kinds of new transmission strategies with network coding are carefully proposed which based on the characteristic of random network coding and complex field network coding.The main work and results of this paper are as follows:1)An approach,namely as LCHR algorithm,for both reducing the complexity and improving the reliability is proposed.Firstly,a critical path selection algorithm is selected to look for the key paths in the network.Then,the critical path is used as a simple path for establishing the communication subnet-hyperpaths.Finally,a new gossip algorithm which incorporates random network coding and a decentralized algorithm based on gossip are applied to transmit messages in the hyperpaths and decide the nodes which should execute encoding operation.The LCHR algorithm,which based on random network coding and is different from that of previous scheme,can reduce the communication cost effectively as well as improve the reliability of the whole network.Simulation results verifies the performance advantages of this method.2)A new pre-coding scheme named JTD-CFNC,which based on complex field network coding,is proposed.Firstly,an equiphase precoder scheme which used for choosing ? of complex field network coding is presented to acquire lower SEP(Symbol Error Probability).Meanwhile,a novel pre-coding scheme,in whichboth the sender and receiver are jointly designed,is proposed to gain higher channel capacity as well as improve it's resistance to interference.The theoretical analysis and simulation results show that the JTD-CFNC significantly outperforms its counterparts both in reducing the SEP and increasing the channel capacity of the whole system without channel state information at the transmitter.