Service Duration Maximization for Continuous Coverage in UAV-Assisted Communication System

This letter studies a UAV-assisted communication design where a rotary-wing UAV is launched to provide continuous coverage to mobile nodes. We aim to maximize the service time duration of the UAV by optimizing its three-dimensional (3D) trajectory while simultaneously ensuring adequate coverage to mobile nodes. Considering the limited energy available with the UAV, we frame an equivalent energy consumption minimization problem. Though the formulated problem is non-convex, it is shown that it is pseudoconvex under horizontal and vertical UAV coordinates. Based on this observation, we use alternating optimization to solve the problem. Numerical results provide trajectory insight and compare the service duration to the mobile nodes with different schemes.