Outage analysis of spectrum sharing relay systems with multi-secondary destinations in the presence of primary user's interference

This paper investigate the impact of primary transceivers on the outage performance of a dual-hop decode-and-forward (DF) spectrum sharing relay system with multiple secondary user (SU) destinations in Nakagami-m fading channels. To doing so, we derive new exact and asymptotic closed-form expressions for the outage probability of spectrum sharing relay systems employing the opportunistic scheduling algorithm, which readily enable us to characterize the impact of various key system parameters on the outage performance of the system. Monte Carlo simulation results are provided to verify the theoretical analysis and evaluate the effects of channel fading severity, SU relay placement, and number of SU destinations. The finding of this paper suggests that the interference temperature constraint results in the outage saturation phenomenon and zero diversity gain of spectrum sharing relay systems.