Joint Optimization of Multiple UAV-mounted RISs Deployment and RIS Elements Allocation

This paper considers deploying multiple UAV- mounted reconfigurable intelligent surfaces (RISs) to reflect signals from the base station (BS) to users to provide line- of-sight (LoS) communications. We aim to jointly optimize the deployment of UAV-mounted RISs, the assignment of RIS elements to users, and the BS power allocation to minimize the number of required UAVs while satisfying the user signal-to- noise ratio (SNR). To achieve the above goal, we divide the area of interest (AOI) into grid cells and propose an integer linear programming (ILP) model. Numerical results show that the proposed ILP model outperforms the baseline scheme under the constraints of user SNR thresholds and successfully serving all users.