Performance Analysis of Releay Selection Scheme for Amplify and Forward Protocol in Rayleigh Fading Environment

In this paper a relay selection scheme for amplify and forward relaying is proposed to select one relay from multi-relay networks. The selected relay by the proposed algorithm cooperates only if the signal to noise ratio (SNR) of the source-relay-destination link is greater than the SNR of the source-destination link. A theoretical bit error rate performance of the proposed scheme is derived. Computer simulations are performed to validate the theoretical developments. The outage probability of the proposed scheme is simulated for different threshold value. Moreover, a power allocation algorithm based on bit error rate minimization is applied. The performance of the proposed relay selection scheme is compared with other existing schemes. The simulation is performed for known and estimated channels. Channel estimation is performed by least square algorithm and the effect of the channel estimation error on the performance of the algorithm is investigated. Numerical results show that the proposed algorithm has better performance than some of the other relay selection algorithms. Moreover, the proposed algorithm saves the power since the selected relay participates only when the total signal to noise ratio of the direct link is weak.