Localization via Multiple Reconfigurable Intelligent Surfaces Equipped with Single Receive RF Chains

TL;DR

This paper introduces a high-accuracy user localization method using multiple reconfigurable intelligent surfaces with a single RF chain, combining direction estimation and maximum likelihood techniques.

Contribution

It presents a novel localization approach leveraging RIS hardware with a single RF chain, including a new estimation algorithm and theoretical analysis.

Findings

High localization accuracy demonstrated in simulations

Effective initial direction estimation method

Theoretical analysis confirms estimation performance

Abstract

The extra degrees of freedom resulting from the consideration of Reconfigurable Intelligent Surfaces (RISs) for smart signal propagation can be exploited for high accuracy localization and tracking. In this paper, capitalizing on a recent RIS hardware architecture incorporating a single receive Radio Frequency (RF) chain for measurement collection, we present a user localization method with multiple RISs. The proposed method includes an initial step for direction estimation at each RIS, followed by maximum likelihood position estimation, which is initialized with a least squares line intersection technique. Our numerical results showcase the accuracy of the proposed localization, verifying our theoretical estimation analysis.