Ergodic Capacity of Intelligent Omni-Surface-Aided Communication Systems With Phase Quantization Errors and Outdated CSI

In this article, we study the performance of an intelligent omni-surface (IOS)-aided communication system, considering the impacts of actual phase quantization errors and outdated channel state information (CSI). Different from the conventional reflective reconfigurable intelligent surface that can only reflect the incident signals, IOS can offer effective communication service to mobile users via the reflective or the transmissive operation. As for the transmissive scenario, we derive the accurate closed-form ergodic capacity (EC) expressions taking into account the phase quantization errors in both the near- and far-fields. To further obtain practical physical insights, tight upper- and lower-bound expressions for EC are provided. It is found that when the transmit power and the quantization bits are sufficiently large, the EC performance would become saturated due to the existence of outdated CSI. Also, the impacts of the phase quantization errors, the outdated CSI, and channel parameters on the considered system performance are revealed. Furthermore, the correctness of our derived expressions is validated by extensive Monte-Carlo simulation results.