The Research About Physical Layer Performance Of Communication Network Under Different Relay Behavior

Cooperative communication is designed to improve signal to noise(SNR) by relay forwarding and combining each signal of receiving end. In wireless communication, SNR, security and bit error rate are important parameters to measure the pros and cons of the system. In the actual communication system, the relay behavior is varied, which makes the relay's signal different, and the combined signal may produce different.This paper is based on classical three-node model, studying the system performance in different behavior of relay under Rayleigh fading channels. This article discusses the completely cooperative behavior, selfish behavior and malicious behavior. This paper did system performance simulation under different relay behavior with Matlab to obtain optimal performance for power distribution. The results show that completely cooperative behavior of relay can improve the system performance of bit-error. When the total system power is constant, there exists an optimal power allocation to obtain the optimal performance of the system. We can get different bit-error performance and safety performance with selfish behavior and malicious behavior of relay under different merger methods. Also there exists an optimal power allocation to obtain the optimal performance of the system.This paper determined the experimental program based on USRP and GNU Radio, building an experimental model of three-node communication. In the experiment, we simulated the relay's behavior by changing power parameters. We got two signals of source to receiver and relay to receiver. To make the data more accurate, we sent multiple sets of data in each experiment, then we processed data with Matlab data to obtain statistical average, so that we can study the impact on system performance in practice to achieve the combination of theory and experiment.