Secrecy performance of cognitive radio networks with optimal source selection under the impact of unreliable backhaul

In this paper, the effect of unreliable wireless backhaul on the secrecy performance of cooperative half-duplex cognitive relay networks (CRN) comprised of multiple primary users and multiple eavesdroppers is studied. We consider relay networks with single relay applying Optimal Source Selection (OSS) scheme, and obtain exact closed-form and asymptotic expressions for secrecy outage probability. Monte Carlo simulations are also operated to validate the correctness of our analysis. The outcomes demonstrate that OSS strategy is capable of counteracting the negative impact of unreliable backhaul on CRN. Furthermore, the secrecy performance of the system converges to an asymptotic limit in high-SNR ranges that is only dependent on the backhaul reliability and the order of selected source.