The underlay cooperative cognitive network with secure transmission

In this paper, we propose and analyze an underlay cooperative cognitive network with Physical Layer Security where a best relay is selected based on maximizing end-to-end secrecy capacity. The cooperative system performance is evaluated by an outage secrecy probability and is compared with the direct transmission protocol. Our simulation results show that system performance is improved when d
_se
> d
_sd
and the cognitive network is far enough from the primary user, where d
_sd
and d
_se
are the distances from a source to a destination and a source to an eavesdropper, respectively. In addition, the theoretical expressions match well with the simulation results.