Energy efficiency maximization via UAV-mounted intelligent reflection surface

Abstract

Different from conventional amplify-and-forward relays, which have two-steps that receive the transmission signal from the base station (BS) and beamforming to the receiver, the intelligent surface (IRS) changes the phase of the incoming signal and reflects it in one step. The IRS, which increases the receiver's data rate by adjusting only the phase, does not need to change the existing system environment. Therefore, it has significant advantages over existing relays in terms of ease of installation, cost, and additional energy consumption required to operate. We are working to increase the energy efficiency of UAV-aided wireless communication system by installing IRS in UAV, which making up for the drawbacks of high energy consumption during flying. The study first sets the channel environment considering the probability of line of sight (LoS) according to the elevation and 2D position of the UAV, and then optimizes the 3D position of the UAV accordingly. In the following process, "study to find suitable phase to increase energy efficiency for each channel environment", "research on iterative algorithm which jointly optimizes positioning and phase matrix of UAV" is progressed. In addition, we also proceed to "develop algorithms to find phase shift values that can achieve suboptimal results without exhaustive search".