Configuring reconfigurable intelligent surfaces using a practical codebook approach

Abstract

It is proven that the scattering, reflection, and refraction properties of electromagnetic signals can be adapted and managed by using reconfigurable intelligent surfaces (RISs). In this paper, we have investigated the performance of a single-input-single-output (SISO) wideband system in terms of achievable data rate by optimizing the phases of RIS elements and performing a fair power allocation for each subcarrier over the entire bandwidth. A new beamforming codebook is developed from which the maximizing signal-to-noise (SNR) configuration is selected. The channel state information (CSI) along with the selected maximizing SNR configuration is then used by the proposed power algorithm to obtain the optimal configuration of the RIS. To validate our proposed method, it is compared with state-of-the-art semidefinite relaxation (SDR) scheme in terms of performance, complexity and run-time consumption. Our method shows dramatically lower computational complexity than the SDR method and achieves an order of 2.5 increase in the achievable data rate with an optimized RIS compared with an un-configured surface.

Architecture for sub-100 ms liquid crystal reconfigurable intelligent surface based on defected delay lines

“…Recently, reconfigurable intelligent surfaces (RISs) have gained widespread attention concerning their potential impact in novel millimeter wave (mm-Wave) and terahertz (THz) systems [1][2][3][4][5] . Due to their passive nature, these large tunable reflectors represent a cost-and power-effective approach to overcome challenges in achieving reliable and robust communication links.…”