Secrecy Performance Analysis of IRS-Aided UAV Relay System

In this letter, we study the secrecy performance of an intelligent reflecting surface (IRS)-aided unmanned aerial vehicle (UAV) relay communication system in the presence of multiple ground eavesdroppers (Eves). Specifically, a UAV equipped with an IRS is deployed as a passive relay to forward the signals transmitted from the base station to users. By modeling the distribution of Eves with stochastic geometry theory and taking the estimation errors into account, we extract the novel expressions for the statistical characterizations of the signal-to-noise ratio, for both legitimate receiver and Eves. For completeness, different eavesdropping channels are investigated, namely, the cooperative and independent Eve cases. The secrecy outage probability (SOP) is analytically evaluated to unveil the impact of the number of reflecting elements and the location of UAV on SOP performance. Finally, numerical results corroborate the theoretical analysis.