Adaptive Beamforming Design for mmWave RIS-Aided Joint Localization and Communication

Abstract

The concept of reconfigurable intelligent surface (RIS) has been proposed to change the propagation of electromagnetic waves, e.g., reflection, diffraction, and refraction. To accomplish this goal, the phase values of the discrete RIS units need to be optimized. In this paper, we consider RISaided millimeter-wave (mmWave) multiple-input multiple-output (MIMO) systems for both accurate positioning and high datarate transmission. We propose an adaptive phase shifter design based on hierarchical codebooks and feedback from the mobile station (MS). The benefit of the scheme lies in that the RIS does not require deployment of any active sensors and baseband processing units. During the update process of phase shifters, the combining vector at the MS is also sequentially refined. Simulation results show the performance improvement of the proposed algorithm over the random design scheme, in terms of both positioning accuracy and data rate. Moreover, the performance converges to exhaustive search scheme even in the low signal-to-noise ratio regime.

Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead

“…In [280], the authors investigate the design of millimeterwave MIMO wireless networks with joint communication and localization capabilities. This authors show that the use of RISs is beneficial for both tasks, granting both accurate positioning and high data-rate transmission.…”

Joint beamforming for intelligent reflecting surface aided wireless communication using statistical CSI

“…3) Under the assumption of perfect estimation, i.e. no estimation error, the approximate closed-form expressions in (37) and (38) coincide with the original (32) and ( 33), testifying the correctness of the derivations in Appendix C. 37) and (38), while the marks with legend "Original" represent the results of (32) and (33). The discrete marks represent the results averaged on 50 Monte Carlo trials.…”

Radio Localization and Mapping With Reconfigurable Intelligent Surfaces: Challenges, Opportunities, and Research Directions

“…The signals from an RIS can be shaped by the RIS controller to further improve accuracy when the RIS is acting as a transmitter or a reflector [6], [7]. The design may, however, be less flexible than the signal from a conventional BS for obvious power and complexity considerations.…”

“…These properties and their close relation to the environment geometry make RISs attractive for localization and mapping. The potential of RISs for localization has received only limited coverage in the literature, including preliminary studies where an RIS operates in receive mode as a lens [6] and in reflection mode [7]. Hence, it is timely to delve deeper into the potential of RISs for localization and mapping as well as the main research questions to be addressed in the coming years.…”

“…Possible applications of RISs for localization are visualized in Figure 2. This article aims to take a broader view than the technical contributions in [6] and [7] by describing the core technical challenges of applying RISs to localization and mapping, along with a preliminary system vision, results, and solutions recently put forward on related topics.…”