Modeling RIS from Electromagnetic Principles to Communication Systems–Part II: System-Level Simulation, Ray Tracing, and Measurement

In this paper, we systematically study the electro-magnetic (EM) and communication aspects of a RIS through EM simulations, system-level and ray tracing 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 one to four-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 ray tracing simulation results show good agreement with the measurement results. It is proved that the introduced macroscopic model of a 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 a RIS could be tailored to, e.g., the wireless communication system engineers in the cellular network planning business, providing tools to optimize network performance.