COMPARATIVE STUDY OF RELAY PROTOCOLS USING SIMULATION

Cooperative communication has gained a lot of interest due to its ability to exploit the spatial diversity or antenna diversity. The implementation of the cooperative relaying systems involves less hardware and lowcomplexity but gives comparable performance and diversity gains to the actual multiple antenna systems. The aim of this paper is to compare various techniques used in cooperative relaying protocols. The performanceis evaluated in terms of average symbol error under various ranges of signal-to-noise ratio (SNR) probabilities. A three node system i.e. source, relay and destination, placed on the edges of equilateral triangle, has been proposed using Maximal ratio Combiner (MRC) method by combining signals from source and relay at destination point. The transmission path is modeled as a frequency non-selective Rayleigh fading in the presence of additive white Gaussian noise (AWGN). The results show that at high SNR decode-and-forward performs well, while at low SNR amplify-and-forward works well. A selective relaying scheme called selective detect-and-forward is also simulated which shows better performance than its fixed counterparts for a wide range of SNR