Outage Analysis of IRS-Aided Wireless Energy Transfer Under Correlation and Imperfect CSI

Outage analysis of intelligent reflecting surface (IRS) assisted wireless energy transfer to multiple users based on round-robin scheduling strategy under imperfect channel state information (CSI), spatial correlation and optimal phase configuration is presented. For this, we develop a statistical model based on Gamma distribution for a random variable that is a function of reflected channels via IRS. This analysis accounts for the correlation among the IRS elements and also the correlation that results due to common source to IRS channels for different users. Through numerical results, we show the robustness of our system against imperfect CSI, and validate the tightness of our modelling and analysis. We quantify the improvement in outage that can be achieved by systems that employ optimal phase shift configuration at IRS over systems that employs either random or equal phase shift programming. We also show that even under estimation errors, more users can be supported by increasing the number of IRS elements. We also observe that estimation errors induce a marginal degradation in outage performance.