Intelligent Reflecting Surface Aided Communication Systems: Performance Analysis

In this paper, we investigate an intelligent reflecting surface (IRS) aided wireless system adopting a finite number of IRS elements with and without a direct path between access point (AP) and the user. Assuming the maximum received power, we present the bit error rate (BER) and average achievable rate (AAR) analysis of IRS-based systems. In particular, we derive a closed-form BER approximation, which enables us to predict the asymptotic performance variation with signal-to-noise ratios (SNRs) and the number of IRS elements. Further, we derive an upper bound on AAR with direct path, then tight upper and lower bounds on AAR without direct path. Simulation results demonstrate that our analysis offers more accurate BERs than the existing works and all bounds are very close to simulated AARs.