RIS-Enabled SISO Localization under User Mobility and Spatial-Wideband Effects
Journal article, 2022

Reconfigurable intelligent surface (RIS) is a promising technological enabler for the 6th generation (6G) of wireless systems with applications in localization and communication. In this paper, we consider the problem of positioning a single-antenna user in 3D space based on the received signal from a single-antenna base station and reflected signal from an RIS by taking into account the mobility of the user and spatial-wideband (WB) effects. To do so, we first derive the spatial-WB channel model under the far-field assumption, for orthogonal frequency-division multiplexing signal transmission with the user having a constant velocity. We derive the Cram\'er Rao bounds to serve as a benchmark. Furthermore, we devise a low-complexity estimator that attains the bounds in high signal-to-noise ratios. Our estimator neglects the spatial-WB effects and deals with the user mobility by estimating the radial velocities and compensating for their effects in an iterative fashion. We show that the spatial-WB effects can degrade the localization accuracy for large RIS sizes and large signal bandwidths as the direction of arrival or departure deviate from the RIS normal. In particular, for a 64 $\times$ 64 RIS, the proposed estimator is resilient against the spatial-WB effects up to 140 MHz bandwidth. Regarding user mobility, our results suggest that the velocity of the user influences neither the bounds nor the accuracy of our estimator. Specifically, we observe that the state of the user with a high speed (42 m/s) can be estimated virtually with the same accuracy as a static user.

Reconfigurable intelligent surface

position error bound

Cramer-Rao bound

Synchronization

spatial-wideband

Three-dimensional displays

Wireless communication

radio localization

Channel models

Estimation

Location awareness

Channel estimation

Author

Kamran Keykhosravi

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

Furkan Keskin

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

G. Seco-Granados

Universitat Autonoma de Barcelona (UAB)

Petar Popovski

Aalborg University

Henk Wymeersch

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

IEEE Journal on Selected Topics in Signal Processing

1932-4553 (ISSN) 19410484 (eISSN)

Vol. 16 5 1125-1140

Multi-dimensional Signal Processing with Frequency Comb Transceivers

Swedish Research Council (VR) (2018-03701), 2018-12-01 -- 2021-12-31.

Reconfigurable Intelligent Sustainable Environments for 6G Wireless Networks

European Commission (EC) (EC/2020/101017011), 2021-01-01 -- 2023-12-31.

Subject Categories

Telecommunications

Communication Systems

DOI

10.1109/JSTSP.2022.3175036

More information

Latest update

12/27/2022