Physical Layer Security Analysis of IRS-Aided UAV Relaying Systems with NOMA

This paper investigates the secrecy outage performance of a passive intelligent reflecting surface (IRS)-assisted unmanned aerial vehicle (UAV) relaying system with non-orthogonal multiple access (NOMA). The focus is on the secrecy outage aspect, where confidential messages are transmitted from a base station to multiple intended recipients while being vulnerable to interception by an eavesdropper. The aerial channels are assumed to experience line-of-sight (LoS) Rician fading, while the terrestrial channels encounter non-line-of-sight (non-LoS) Rayleigh fading. The exact closed-form expressions are derived for secrecy outage probability (SOP) and the strictly positive secrecy capacity (SPSC), which incorporate the impact of the number of reconfigurable reflecting elements and the value of the considered secrecy rate threshold. Furthermore, analytical expressions for the asymptotic SOP are derived to gain deeper insights. Monte Carlo simulations are conducted to validate the analytical findings.