The AF protocol of cooperative communication system

Abstract

Wireless communication system using cooperative transmission technology, at the receiving node by combining data samples from multiple independent fading channel, can effectively resist the influence of channel fading, obtain diversity gain, and improve the transmission reliability of the system. The purpose of cooperative communication technology is to solve the problem of communication effectiveness. This article expounds the amplify-and-forward(AF) protocol of the cooperative relay technology that is one of the key technology in cooperative communication technology, and discusses its ergodic capacity(EC). Theory proves that two-way relay can greatly improve the rate of information transmission 2. The protocol of two-way relay system Considering a two-way relay communication system, the user nodes-A and B exchange information each other. But because there is no direct link between A and B, and needs to forward information through the relay node-R, as shown in Fig. 1[3]. Supposing the system goes through flat fading, and adopts time-division duplex mode, then the channels are reciprocity. Take the system as shown in Fig. 1 as an example to discuss the different protocols two-way relay system.