RIS in Indoor Environments: Benchmarking Against Ambient Propagation

TL;DR

This paper evaluates the true impact of reflective intelligent surfaces (RIS) in indoor environments by comparing their signal enhancement to natural environmental reflections using a physics-based model.

Contribution

It introduces a rigorous physics-based approach to benchmark RIS performance against ambient propagation in indoor settings, highlighting environmental effects.

Findings

Environmental reflections contribute energy comparable to large RIS.

RIS impact is limited unless significantly larger than environmental reflections.

Natural reflections can overshadow RIS effects in typical indoor scenarios.

Abstract

The improvements in received signal power brought about by a reflective intelligent surface (RIS) might be overstated if background propagation mechanisms such as reflections, scattering, and diffraction are ignored. This paper addresses this issue for non-line-of-sight indoor settings, contrasting the energy conveyed by an RIS with the energy already reaching the receiver through environmental reflections. And, to prevent artifacts, such naturally occurring reflections are not modeled via approximate methods, but rather through a rigorous physics-based formulation. It is found that the environment contributes a level of energy commensurate with that of an ideal RIS of considerable size; to have substantial impact, an actual RIS would have to generously exceed this size.