Beyond 5G Wireless Localization with Reconfigurable Intelligent Surfaces

TL;DR

This paper explores how reconfigurable intelligent surfaces (RIS) can enhance 5G and beyond wireless localization by controlling electromagnetic wave propagation, proposing an optimization scheme and analyzing performance improvements and limitations.

Contribution

It introduces a RIS-aided downlink positioning framework, analyzing Fisher Information and proposing a two-step optimization for improved localization accuracy.

Findings

Coverage and accuracy improvements over natural scattering.

RIS can significantly enhance positioning performance.

Limitations include low SNR and inter-path interference effects.

Abstract

5G radio positioning exploits information in both angle and delay, by virtue of increased bandwidth and large antenna arrays. When large arrays are embedded in surfaces, they can passively steer electromagnetic waves in preferred directions of space. Reconfigurable intelligent surfaces (RIS), which are seen as a transformative "beyond 5G" technology, can thus control the physical propagation environment. Whereas such RIS have been mainly intended for communication purposes so far, we herein state and analyze a RIS-aided downlink positioning problem from the Fisher Information perspective. Then, based on this analysis, we propose a two-step optimization scheme that selects the best RIS combination to be activated and controls the phases of their constituting elements so as to improve positioning performance. Preliminary simulation results show coverage and accuracy gains in comparison with natural scattering, while pointing out limitations in terms of low signal to noise ratio (SNR) and inter-path interference.