Performance analysis of cognitive relay networks under both average and peak interference power constraints

In this paper, to guarantee the reliable communications of the primary user (PU), we impose a joint constraints on both average and peak interference power. With multiple relays available, the performance for proactive decode-and-forward (DF) relaying is investigated in underlay cognitive relay networks. Particularly, considering the correlation among the received signal to noise ratios (SNRs), exact closed form expressions for the outage probability and ergodic capacity of the secondary user (SU) are derived over Rayleigh fading channels. It is shown that, due to the common links between the SU source and the PU receiver, the performance of the SU is degraded. Finally, simulation results are presented to validate our analytical analysis.