SNR-based Configuration of Reconfigurable Intelligent Surface

A reconfigurable intelligent surface (RIS) can be used to control the propagation of electromagnetic waves (EM). Deployment of RIS units in radio environment allows to steer the transmitted EM waves to areas that are otherwise shadowed by buildings or geographic formations such as hills. Since the RIS is a passive unit in the sense that it does not amplify the impinging wave, its beam pattern must be accurately pointed to the correct direction. The RIS configuration as a solution to an optimization problem for spectral or energy efficiency requires the estimation of the channels between the transmitter and the RIS and between the RIS and the receiver. The channel estimation requires the transmission of training sequences and the receiver must receive and store the received samples during the training before the optimization problem can be solved. The approach proposed in this paper simplifies and speeds up the RIS configuration process by relaxing the demand to find the optimal solution but instead aims to reach a predetermined channel quality measured with the signal-to-noise ratio (SNR).