Sum-Rate Analysis in Reconfigurable Intelligent Surface-Aided UAV Networks

Reconfigurable intelligent surfaces (RIS) have emerged as one of the promising systems for energy efficiency in wireless communications in recent years. In this study, the downlink scenario with an RIS-assisted unmanned aerial vehicle (UAV) networks is discussed. The effect of direct link on the capacity of RIS-assisted systems is examined, taking into account the situations whether there exists link between the users and the UAV. In addition, the optimum phase shift matrix of RIS is obtained by fixed point iteration method. In the simulation results, it has been observed that the direct link between the UAV and the user positively affects the achievable sum-rate when the optimum phase shift matrix is used. In addition, in the absence of a direct link, it is concluded that the user closest to RIS has the highest sum-rate.