Exact Outage Probability of Cooperative Diversity with Opportunistic Spectrum Access

Opportunistic spectrum access, popularly known as cognitive radio technology is an innovative radio design philosophy which aims to increase spectrum utilization by exploiting unused spectrum in dynamic environments. In this paper, we present an exact outage performance analysis for the rates of a decode-and-forward cooperative network where a source communicates with its destination using the well- known repetition-based relaying scheme or using the single best relay, i.e, selection cooperation. Closed-form expressions are obtained for independent Rayleigh fading channels. Selection cooperation exhibits lower outage probabilities compared to the repetition-based scheme. However, the inability of relays to sense unoccupied spectrum can cause a larger drop in the outage performance of selection cooperation, especially in the high SNR regime. The analytical outage probability expressions have been validated through simulations.