Design and Evaluation of Reconfigurable Intelligent Surfaces in Real-World Environment

Abstract

Reconfigurable intelligent surfaces (RISs) have promising coverage and data rate gains for wireless communication systems in 5G and beyond. Prior work has mainly focused on analyzing the performance of these surfaces using computer simulations or lab-level prototypes. To draw accurate insights about the actual performance of these systems, this paper develops an RIS proof-of-concept prototype and extensively evaluates its potential gains in the field and under realistic wireless communication settings.In particular, a 160-element reconfigurable surface, operating at a 5.8GHz band, is first designed, fabricated, and accurately measured in the anechoic chamber. This surface is then integrated into a wireless communication system and the beamforming gains, pathloss, and coverage improvements are evaluated in realistic outdoor communication scenarios. When both the transmitter and receiver employ directional antennas and with 5m and 10m distances between the transmitter-RIS and RIS-receiver, the developed RIS achieves 15-20dB gain in the signal-to-noise ratio (SNR) in a range of ±60 • beamforming angles. In terms of coverage, and considering a far-field experiment with a blockage between a base station and a grid of mobile users and with an average distance of 35m between base station (BS) and the user (through the RIS), the RIS provides an average SNR improvement of 6dB (max 8dB) within an area > 75m 2 . Thanks to the scalable RIS design, these SNR gains can be directly increased with larger RIS areas. For example, a 1,600-element RIS with the same design is expected to provide around 26dB SNR gain for a similar deployment. These results, among others, draw useful insights into the design and performance of RIS systems and provide an important proof for their potential gains in real-world far-field wireless communication environments.

Autoencoder-based Communications with Reconfigurable Intelligent Surfaces

“…Every element in the N × 1 RIS reflection vector Ψ is implemented using an RF phase shifter. The codebook generation process is described in [25]. Assuming phase shifts of the RIS elements are continuous variables, the RIS reflection vector Ψ * that maximizes the achievable rate R is given by…”

“…Since we assume that the transmitter-RIS and RIS-receiver communication links are dominated by LoS paths [25], the RIS reflection vector can be designed as…”

“…We limit the choice of the reflection beamforming vector to a predefined codebook P with N elements. Each element in the codebook is represented with 1 bit [25].…”

“…2. It was shown in [25] that when both the transmitter and receiver employ directional antennas and the distances between the transmitter-RIS and RIS-receiver are 5m and 10m, respectively, the RIS achieves 15-20dB gain in the signal-to-noise ratio (SNR) at the receiver.…”

Planning of EM Skins for Improved Quality-of-Service in Urban Areas

“…As a matter of fact, the design of advanced metasurfaces with tunable magnitude/phase modulation has been performed by properly extending the RAs/TAs synthesis concepts in order to take into account the presence of finite-size arrangements of sub-wavelengths metallic elements mounted on wall surfaces [12]. However, some unsolved challenges need to be still faced to make RISs an attractive technology for large-scale urban deployments [13] [17]. Indeed, new technological advancements are expected to enable the installation of RISs in wide regions as well as conformal to irregular surfaces with cost-efficient manufacturing, installation, and maintenance, while consuming a low power.…”