Evaluating Beam Sweeping for AoA Estimation with an RIS Prototype: Indoor/Outdoor Field Trials

TL;DR

This paper demonstrates the practical implementation and validation of beam sweeping for AoA estimation using a 1-bit RIS prototype through extensive indoor and outdoor field trials, confirming theoretical models and exploring environmental adaptations.

Contribution

It introduces a real-world RIS configuration method, validates beamforming patterns experimentally, and evaluates AoA estimation and environmental effects in practical scenarios.

Findings

RIS can effectively alter channel properties.

Beam sweeping enables AoA estimation in real-world conditions.

RIS's frequency selectivity impacts indoor deployment strategies.

Abstract

Reconfigurable Intelligent Surfaces (RISs) have emerged as a promising technology to enhance wireless communication systems by enabling dynamic control over the propagation environment. However, practical experiments are crucial towards the validation of the theoretical potential of RISs while establishing their real-world applicability, especially since most studies rely on simplified models and lack comprehensive field trials. In this paper, we present an efficient method for configuring a $1$-bit RIS prototype at sub-$6$ GHz, resulting in a codebook oriented for beam sweeping; an essential protocol for initial access and Angle of Arrival (AoA) estimation. The measured radiation patterns of the RIS validate the theoretical model, demonstrating consistency between the experimental results and the predicted beamforming behavior. Furthermore, we experimentally prove that RIS can alter channel properties and by harnessing the diversity it provides, we evaluate beam sweeping as an AoA estimation technique. Finally, we investigate the frequency selectivity of the RIS and propose an approach to address indoor challenges by leveraging the geometry of environment.