Low-Complexity Joint On-Off Control of Reflecting Elements and Beaforming Design in RIS-Aided Wireless Systems

Effective control of reflecting elements is essential for the development of reconfigurable intelligent surfaces (RIS), which has received restricted focus. In this letter, we introduce three novel strategies involving joint on-off control of reflection elements (OCRE), active beamforming and passive beamforming design schemes intended for the deployment in RIS-assisted networks. The first strategy is with utral-low-complexity which is designed to maximize the channels’ gains (MCG), while the second one introduces a linear exchange (LE) strategy that focuses on optimizing the receive signal power. Besides, for the third strategy, we introduce a global linear exchange (GLE) strategy with swapping of reflecting elements. Finally, extensive numerical results show that both the MCG and the LE are effective in improving the signal-to-noise ratio (SNR) at the receiver and the LE attains a near-optimal performance compared with the exhaustive search but with considerably low complexity.