Modeling RIS From Electromagnetic Principles to Communication Systems—Part II: System-Level Simulation, Ray Tracing, and Measurements

Abstract

In this article, we systematically study the electromagnetic (EM) and communication aspects of an RIS through EM simulations, system-level and ray tracing (RT) simulations, and finally measurements. We simulate a nearly perfect, lossless RIS, and a realistic lossy anomalous reflector (AR) in a ray tracer and analyze the large-scale fading of simple RIS-assisted links. We also compare the results with continuous and quantized unit cell reflection phases with 1–4-bit resolutions. Finally, we perform over-the-air communication link measurements in an indoor setting with a manufactured sample of a wide-angle AR. The EM, system-level, and RT simulation results show good agreement with the measurement results. It is proved that the introduced macroscopic model of an RIS from the EM aspects is consistent with our proposed communication models, both for an ideal RIS and a realistic AR. The verified system-level simulator and ray tracer for an RIS could be tailored to, e.g., the wireless communication system engineers in the cellular network planning business, providing tools to optimize the network performance.