Received SNR Comparison of Hybrid RIS Phase Shift Methods Based on Channel and DOA Estimations

초록

A hybrid reconfigurable intelligent surface (HRIS) is an emerging technology that combines sensors with the reflecting element of a conventional reconfigurable intelligent surface. Because of the hybrid element's receiving (or sensing) capability, the HRIS can estimate the channel or the direction of arrival (DOA), thereby adjusting the optimal phase-shift values to maximize the downlink signal-to-noise ratio (SNR). This study compares the SNR performance of the HRIS phase-shift methods utilizing the estimated channel and the DOA. Numerical simulations verified that the superiority of the two HRIS phase-shift methods depends on the communication channel and system parameters. Specifically, the received SNR of the HRIS phase-shift method with DOA estimation is advantageous over channel estimation for the line-of-sight-dominant channel when the number of pilot symbols and the uplink transmit power are low.

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