Joint Placement and Beamforming Design in Multi-UAV-IRS Assisted Multiuser Communication
Linghui Ge, Hua Zhang, Jun-Bo Wang
Abstract
Intelligent reflecting surface (IRS) is a revolutionizing technology for improving the spectrum and energy efficiency in wireless communications. In this paper, a new communication framework enabled by multiple unmanned aerial vehicle (UAV)-carried intelligent reflecting surfaces (IRSs) is proposed to enhance multiuser downlink transmissions. To take full advantage of multi-UAV-IRS assisted system, we formulate the problem as maximizing the downlink sum rate by jointly optimizing the placement of UAVs, active beamforming and power allocation at the BS, and passive beamforming at the IRSs. An efficient algorithm is proposed by invoking successive convex approximation technique to decompose the joint optimization problem into several subproblems, which can be solved in an iterative manner. Simulation results show that the proposed scheme achieves considerable sum rate gain, which outperforms other benchmark schemes.