SISO RIS-Enabled Joint 3D Downlink Localization and Synchronization
Paper in proceeding, 2021

We consider the problem of joint three-dimensional localization and synchronization for a single-input single-output (SISO) multi-carrier system in the presence of a reconfigurable intelligent surface (RIS), equipped with a uniform planar array. First, we derive the Cramér-Rao bounds (CRBs) on the estimation error of the channel parameters, namely, the angle-of-departure (AOD), composed of azimuth and elevation, from RIS to the user equipment (UE) and times-of-arrival (TOAs) for the path from the base station (BS) to UE and BS-RISUE reflection. In order to avoid high-dimensional search over the parameter space, we devise a low-complexity estimation algorithm that performs two 1D searches over the TOAs and one 2D search over the AODs. Simulation results demonstrate that the considered RIS-aided wireless system can provide submeter-level positioning and synchronization accuracy, materializing the positioning capability of Beyond 5G networks even with single-antenna BS and UE. Furthermore, the proposed estimator is shown to attain the CRB at a wide interval of distances between UE and RIS. Finally, we also investigate the scaling of the position error bound with the number of RIS elements.

position error bound

Cramér-Rao bound

Reconfigurable intelligent surface



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)

Henk Wymeersch

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

IEEE International Conference on Communications

15503607 (ISSN)

2021 IEEE International Conference on Communications, ICC 2021
Virtual, Online, Canada,

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

A New Waveform for Joint Radar and Communications Beyond 5G

European Commission (EC) (EC/H2020/888913), 2020-09-01 -- 2022-08-31.

Subject Categories


Communication Systems

Signal Processing



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