On Deployment Position of RIS in Wireless Communication Systems: Analysis and Experimental Results

A reconfigurable intelligent surface (RIS) is capable of altering the wireless channel and thus can assist wireless transmission where the direct path is blocked. The deployment position of RIS between the base station (BS) and the user equipment (UE) can greatly affect the system performance. In this letter, a RIS deployment strategy for RIS-assisted wireless communication systems is proposed. This strategy unveils that the optimal RIS location to maximize the received signal power is not always close to the BS or the UE, but in fact depends on the relationship between the distance from BS to UE and the distance from RIS to BS-UE line. In addition, a fabricated RIS operating at 35 GHz is used in a deployment measurement campaign carried out in indoor office room, outdoor high-building, and narrow corridor scenarios. Numerical simulations and experimental results in each scenario validate the effectiveness of the proposed deployment strategy, which may help RIS deployment in future wireless networks.