Secrecy Performance Analysis and Optimization of Intelligent Reflecting Surface-Aided Indoor Wireless Communications

This paper studies the secrecy performance of an intelligent reflecting surface (IRS)-aided indoor wireless communication where the IRS is capable of adjusting the direction and phase shift of reflected signal on its surface and assists a source to communicate with an authenticated user in the presence of several unauthenticated users, which can be potential eavesdroppers. The goal of this paper is to design a tile-allocation-and-phase-shift-adjustment (TAaPSA) strategy for the IRS to optimize the average secrecy rate (ASR); moreover, the respective secrecy outage probability (SOP) for this TAaPSA is evaluated. To achieve this goal, the ray model and the Rice distribution are adopted to describe the propagation of the IRS's reflected signals and the fading process, respectively. Closed-form analytical expressions for the ASR and the SOP are derived. Using these analytical results, a genetic algorithm (GA) is utilized to find an optimal TAaPSA strategy for the IRS. The accuracy of the analytical results and the improvement in ASR using GA-based TAaPSA strategy are verified by simulation results.