Reconfigurable Intelligent Surfaces for Localization: Position and Orientation Error Bounds

By Ahmed Elzanaty, Anna Guerra, Francesco Guidi, Mohamed-Slim Alouini. IEEE Transactions on Signal Processing, 2020

332 citations recorded by the source corpus.

Next-generation cellular networks could witness the creation of smart radio environments (SREs), where walls and objects will be coated with reconfigurable intelligent surfaces (RISs) to strengthen the communication and localization performance. In fact, RISs have been recently introduced not only to overcome communication blockages due to obstacles but also for high-precision localization of mobile users in GPS denied environments, e.g., indoors. Towards such a vision, this paper presents the localization performance limits for communication scenarios where a single next generation NodeB base station (gNB), equipped with multiple antennas, infers the position and the orientation of a user equipment (UE) in a reconfigurable intelligent surface (RIS)-assisted smart radio environment (SRE). We consider a signal model that is valid also for near-field propagation conditions, as the usually adopted far-field assumption does not always hold, especially for large RISs. For the considered scenario, we derive the Cramér-Rao lower bound (CRLB) for assessing the ultimate localization and orientation performance of synchronous and asynchronous signalling schemes. In addition, we propose a closed-form RIS phase profile that well suits joint communication and localization, and we perform extensive numerical results to assess the performance of our scheme for various localization scenarios and for various RIS phase design. Numerical results show that the proposed scheme can achieve remarkable performance even in asynchronous signalling, and that the proposed phase design, based on signal-to-noise ratio (SNR), approaches the numerical optimal phase design that minimizes the CRLB.

Subfields: Electrical and Electronic Engineering, Ocean Engineering

View Paper: https://www.semanticscholar.org/paper/fb055a88b83d05c97ff6791e4b3b7b65f244710c

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Citations in the corpus

An Overview of Signal Processing Techniques for RIS/IRS-Aided Wireless Systems (2021, neutral): “The authors of [226] derived the CRB for evaluating the localization and orientation performance of synchronous and asynchronous signalling schemes in an RIS-assisted localization system in near-field conditions.”
Convergent Communication, Sensing and Localization in 6G Systems: An Overview of Technologies, Opportunities and Challenges (2021, background): “Localization performance bounds of IRS-assisted smart radio environments in which a BS infers the position and orientation of a UE are derived in [36].”
Beam Focusing for Near-Field Multi-User MIMO Communications (2021, background): “This implies that the far-ﬁeld model, assuming plane wavefronts of the electromagnetic (EM) ﬁeld rather than spherical ones, no longer holds at practical distances [6]–[8].”
Holographic MIMO Communications: Theoretical Foundations, Enabling Technologies, and Future Directions (2022, methodology): “Additionally, passive HMIMOS aided localization is studied in [278] obtaining the CRLB of ultimate localization and orientation, and providing a closed-form phase”
Reconfigurable Intelligent Surfaces: A signal processing perspective with wireless applications (2021, positive): “This property can also be utilized for improved localization [41].”
The Integrated Sensing and Communication Revolution for 6G: Vision, Techniques, and Applications (2024, positive): “Alternatively, low-cost hardware, such as RISs, can be deployed to provide additional controlled multipath components [112], [113].”