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

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.

6G Localization and Sensing in the Near Field: Features, Opportunities, and Challenges

“…This scenario is similar to L1-(b) by replacing an ELAA with a single antenna transmitter/receiver working together with an RIS. In addition, NF features can provide more L&S opportunities in sidelink localization (L2-(b)) in out-of-coverage areas, where more details describing the scenarios can be found in [3].…”

“…of ELAAs and RISs provide unparalleled angular resolution (signal wavelength divided by the physical array aperture size), which directly improves the L&S performance. Moreover, by acting as extra anchor nodes, RISs can support and enable various (and sometimes extremely challenging) scenarios, such as single-input single-output (SISO) [2] and out-of-coverage systems [3]. As for D-MIMO, the spatial diversity and the exploitation of phase-coherence can significantly boost L&S performance [4].…”

Adaptive DCS-SOMP for Localization Parameter Estimation in 5G Networks

“…First, the estimation of localization parameters extracted from the received signal. Second, using the acquired parameters from the first step, a localization method is employed to determine the position of the mobile station (MS) [5,8,9]. Regarding the first step, we highlight several aspects of the literature.…”