Flying Intelligent Surfaces: Joint Adjustment of Position and Configuration for UAV-Mounted RIS

Reconfigurable intelligent surfaces (RIS) are a technology expected to meet the demanding objectives of future wireless networks by manipulating and reflecting electromagnetic waves using real-time adjustable elements to improve communication performance. However, due to multiplicative path loss, RIS are most effective when used in line-of-sight and proximity to the transmitter or receiver. Moreover, as mobility is a common feature in wireless communication networks, guaranteeing these requirements can be challenging — unless the RIS has the ability to reposition itself.To investigate the efficacy of RIS for improving communication quality in such networks, we mounted a RIS prototype on an unmanned aerial vehicle (UAV). By conducting experimental measurements and recording the UAV-mounted RIS trajectory during its flights, the measured data was reconstructed through numerical simulations to extract the key factors. To further bridge simulations and measurements, we extract the gain characterizing the improvement in communication performance resulting from real-time adjustments of the RIS configuration, compared to a fixed configuration. Numerical evaluations indicate that a real-time adjusted RIS may result in a gain of up to 20dB.