Optimal Reconfigurable Intelligent Surface Placement in Millimeter-Wave Communications

In this work, we examine the use of reconfigurable intelligent surfaces (RISs) to create alternative paths from a transmitter to a receiver in millimeter-wave (mmWave) networks, when the direct link is blocked. In this direction, we evaluate the end-to-end signal-to-noise ratio (SNR) expression of the transmitter-RIS-receiver links that take into account the transmitter-RIS and RIS-receiver distances and enables us to acquire important insights regarding the RIS position that maximizes it. Finally, the insights are corroborated by numerical results.