A wireless communication system is studied that operates in the presence of multiple reconfigurable intelligent surfaces (RISs). In particular, a multi-operator environment is considered where each operator utilizes an RIS to enhance its communication quality. Although out-of-band interference does not exist (since each operator uses isolated spectrum resources), RISs controlled by different operators do affect the system performance of one another due to the inherently rapid phase shift adjustments that occur on an independent basis. The system performance of such a communication scenario is analytically studied for the practical case where discrete-only phase shifts occur at RIS. The proposed framework is quite general since it is valid under arbitrary channel fading conditions as well as the presence (or not) of the transceiver's direct link. Finally, the derived analytical results are verified via numerical and simulation trial as well as some novel and useful engineering outcomes are manifested.

翻译：本文研究了一种在多个可重构智能表面（RIS）共存环境下运行的无线通信系统。具体而言，考虑多运营商场景：每个运营商利用各自独立的RIS提升通信质量。尽管各运营商使用隔离频谱资源从而不存在带外干扰，但不同运营商控制的RIS因独立调整的固有快速相移变化，仍会相互影响系统性能。针对RIS仅实现离散相移的实际场景，本文对上述通信场景的系统性能进行了理论分析。所提出的框架具有广泛适用性，既适用于任意信道衰落条件，也适用于收发端直射链路存在与否的情形。最后，通过数值仿真试验验证了理论推导结果，并揭示了若干新颖且实用的工程结论。