Research On Compute And Forward Network Coding Strategy For Cooperative Communications

Cooperative Communication is a kind of communication method withco-processing of multi-user or multi-terminal to achieve assisting to the originalsingle link. This mode of communication effectively overcome the issues such thatthe transfer rate is low, the anti-interference ability is poor, the effectivecommunication distance is limited, and so on. This novel idea comes mainly fromthe multiple input multiple output (MIMO) system. By using the properties of itsmulti antennas to transmission and reception, MIMO system can achieve thediversity and multiplexing. Virtual MIMO system formed by taking the antennas ofother users or base stations as a MIMO situation provides a theoretical basis for theCooperative Communication. Combined with the popular network codingtechnology, there has been a new breakthrough and development on the CooperativeCommunication. As a important part of cooperative communication, forwardingstrategy taken by the relay node is a key to the reliability and the transmission rateof cooperative communication system. In relay forward strategies, the Compute andForward strategy combining with network coding ideas and advantages of theproposed Lattice code structure, gives a incomparable advantages with thetraditional relay strategies.In this paper, we concentrate on the relay forward strategies with the thebackground of cooperative communication. First, we introduce the cooperativecommunication, relay forward strategies and the technologies they used. Followedby an analysis of the characteristics of different relay forward strategies. Finally, wefocus on the study of the compute and forwarding network coding strategy in thetwo-way relay channel and multi-source multi-relay channel.In this paper, we study and discuss two algorithms based on compute andforward strategy called network coding vector searching algorithm and systemmatrix constructure algorithm in two-way relay channel and multi-sourcemulti-relay channel. In the two-way relay channel, with the supplement to theoriginal algorithm based on FP (Finche-Pohst) methods, we proposed the improvedalgorithm based on FP methods. Which gives a new rational limit to the calculatingradius C, so that the search complexity of network coding vectors significantlyreduced. In the multi-source multi-relay channel, we prefer the overall systemoptimization process rather than the local optimization algorithm applied in the past,in which we construct a network coding system matrix. Improve the search ofoptimal vector to the constructure of a network coding system matrix and propose aparameter setting program. Thus we are able to make the overall system rate optimal. At last, the algorithm parameters are discussed.