RISs and Sidelink Communications in Smart Cities: The Key to Seamless Localization and Sensing

TL;DR

This paper explores how reconfigurable intelligent surfaces and sidelink communications can enable seamless localization and sensing in smart cities, addressing infrastructure challenges and proposing innovative architectures for efficient, ubiquitous coverage.

Contribution

It introduces RIS-enabled localization and sensing architectures tailored for smart cities, highlighting their potential to meet stringent L&S requirements with low-cost, energy-efficient solutions.

Findings

RISs and sidelink communications enhance L&S coverage in smart cities.

Proposed architectures support low-complexity beacons and cooperative localization.

Identified practical issues and open research challenges for implementation.

Abstract

A smart city involves, among other elements, intelligent transportation, crowd monitoring, and digital twins, each of which requires information exchange via wireless communication links and localization of connected devices and passive objects (including people). Although localization and sensing (L&S) are envisioned as core functions of future communication systems, they have inherently different demands in terms of infrastructure compared to communications. Wireless communications generally requires a connection to only a single access point (AP), while L&S demand simultaneous line-of-sight propagation paths to several APs, which serve as location and orientation anchors. Hence, a smart city deployment optimized for communication will be insufficient to meet stringent L&S requirements. In this article, we argue that the emerging technologies of reconfigurable intelligent surfaces (RISs) and sidelink communications constitute the key to providing ubiquitous coverage for L&S in smart cities with low-cost and energy-efficient technical solutions. To this end, we propose and evaluate AP-coordinated and self-coordinated RIS-enabled L&S architectures and detail three groups of application scenarios, relying on low-complexity beacons, cooperative localization, and full-duplex transceivers. A list of practical issues and consequent open research challenges of the proposed L&S systems is also provided.