Performance Analysis of Cooperative Relay Protocols over Fading Channels

Abstract

Recently, the cellular mobile networks become fast growing to give services with high data rate transmission and more reliable networks. One proven solution for improving the reliability of a wireless channel is to use cooperative relay. It is most efficient technique to combat the fading effect induced by multipath signal propagation. The main objective of this thesis is to investigate the performance relaying protocols over Rayleigh and Nakagami-m fading channels. The Detect and Forward (DeF), Amplify and Forward (AF) and Estimate and Forward (EF) protocols has been used at the relay system. In this thesis, two- hop relay network with one source(S), one relay and one destination (D) is considered. It is implemented under three relay placement topologies, i.e., equilateral, isosceles and linear topologies. To combine the signals from source and relay the maximum likelihood (ML) is implemented as detector. The metric used for measure the performance of relaying protocols is expressed in terms of Bit error rate (BER) versus signal to noise ratio (SNR) and BER versus normalized distance between source and relay( ) by using Matlab software. According to simulation results, the cooperative relaying techniques have better performance than point-to-point transmission. However, overall results the EF relay network performs better in terms of BER compared with DeF and AF relay networks. The EF relay protocol hits BER value of at SNR value of 13dB, 12dB and 6dB under equilateral, isosceles and linear topologies respectively. Therefore, linear topology has better system performance, than equilateral and isosceles topologies.