Performance of Multiple Selection Diversity Antennas at the Relay Input for Relaying System

In this work we consider a relayed transmission link where the relay is equipped with multiple (N) diversity antennas at their inputs and employs selection combining (SC) technique to improve reception from the source before retransmission to the destination via single transmit antenna. The statistical properties of such a link are studied for N Rayleigh-fading channels. The outage probabilities and the average bit error rates of the proposed link at the receiving end are also derived in closed form for both amplify-and-forward mode and decode-and-forward mode and the results are compared with that of conventional single input relay (i. e., for N = 1). Numerical results show that the system performance improves significantly for N = 2 over that for N = 1 in both low and high signal-to-noise ratio. However, little additional performance improvement can be achieved for N > 2 relative to N = 2 at high SNR.