Joint Trajectory and Velocity-Time Optimization for Throughput Maximization in Energy-Constrained UAV

In this article, we aim to study an unmanned aerial vehicle (UAV)-assisted Internet of Things (IoT) communication system where a rotary-wing UAV travels from the initial to the final location to communicate with multiple IoT ground devices. The limited onboard energy of the UAV poses a constraint to the overall system’s performance. UAV’s energy consumption is majorly based on its kinematics, i.e., UAV’s velocity and acceleration. Therefore, in this work, we maximize the sum user throughput by jointly optimizing the 3-D UAV trajectory, and velocity-time profile in the presence of onboard energy, velocity, acceleration, and completion time constraints. Noting the nonconvexity of the optimization problem, the original problem is decoupled into two subproblems. First, the trajectory is optimized considering the velocity constraint, while in the second subproblem, the velocity and time optimization in each time slot is carried out. Simulation results show insights on the UAV trajectory and velocity-time profile with the variation in the onboard energy availability. In addition, we demonstrate the superior performance of the proposed approach in comparison to the benchmark schemes.