Performance Analysis for RIS-Aided Wireless Systems With Imperfect CSI

The impact of imperfect channel state information (CSI) on a reconfigurable intelligent surface (RIS)-aided wireless system is investigated in this letter. More specifically, considering the imperfect CSI from the RIS to the destination, we develop the cumulative distribution function (CDF) of the end-to-end signal-to-interference-plus-noise ratio (SINR). Then, using the CDF, we derive the closed-form expressions of the outage probability (OP), average bit error rate (BER), and average capacity. Furthermore, we also derive the asymptotic OP, average BER, and average capacity at high signal-to-noise ratio (SNR). Simulation results show that inaccurate CSI results in zero diversity order and a floor phenomenon. Also, numerical results demonstrate that the derived closed-form expressions match the simulated results.