Covert Transmission of RIS-Aided Communication Networks in the presence of Imperfect CSI and Hardware Impairments

In this work, the covert communication performance for reconfigurable intelligent surface (RIS) based communication systems in the presence of a warden is analyzed. In particular, taking the hardware impairment (HI) and the imperfect channel state information (CSI) into consideration, we derive the accurate expressions of the key performance metrics, including the detection error probability (DEP) and covert rate. In addition, through the asymptotic analysis, the influence of the number of reflecting elements, noise uncertainty coefficient, and the parameters related to HI and imperfect CSI on the covert performance is analyzed. Finally, we verify the analytical results by simulation results. Results show that HI and imperfect CSI have adverse effects on the DEP and covert transmission rate, while the use of RISs can improve the covert performance.