Joint 3D Placement and Power Optimization for UAV Communications under Rician Shadowed Channel

This paper proposes a comprehensive framework for optimizing the deployment of Unmanned Aerial Vehicles (UAVs) in a communication system, aiming to minimize the transmission power of UAVs while ensuring the required data rates for ground users. The proposed model accounts for both large- and small-scale fading effects. To accurately capture the characteristics of the wireless channel, the Rician Shadowed fading model is adopted, as it incorporates both line-of-sight (LoS) and nonline-of-sight (NLoS) components. A mathematical formulation of the problem is presented, and the impact of the Rician shadowed fading parameters, the severity of the fluctuations in the LoS component, and the ratio between the powers of the LoS and NLoS components is considered. The simulation results demonstrate that increasing the parameters improves channel conditions, thus reducing the transmission power required to meet the minimum data rate constraints. To address the UAV 3D placement problem, which results in a non-convex and analytically intractable optimization due to the nonlinearities introduced by the channel model. Therefore, we employ a heuristic algorithm, Particle Swarm Optimization Evolutionary (PSO-E).