Outage probability for four relay selection in wireless relay networks

In this paper we evaluate the outage probability in cooperative networks using the channel conditions in order to select the best four relays from a set of N relays and then the chosen relays are used for cooperation between the source and the destination. Expressions for outage probability are derived for a frequency flat Rayleigh-fading environment by using theoretic analysis of the probability function (PDF) and the cumulative density function (CDF) of the received signal-to-noise ratio (SNR). Simulation studies show the outage probability for different numbers of available relays N and the impact on system performance for different numbers of available relays N and the resultant diversity of the proposed modified quasi-orthogonal scheme.