Energy Minimization for UAV Enabled Video Relay System Under QoE Constraints

With the explosive growth of mobile video services, unmanned aerial vehicle (UAV) is flexibly deployed as a relay node to offload cellular traffic or provide video services for emergency scenario without infrastructures. This paper proposes a novel design framework for UAV enabled video relay system with the aim of minimizing energy consumption of the UAV, subjecting to the QoE requirement of each GU. A dynamic resource allocation strategy is employed to model the UAV’s power and bandwidth allocation and the optimization problem is formulated as a non-convex problem, via optimizing the transmit power and bandwidth allocation of the UAV jointly with the UAV trajectory. To tackle this non-convex problem, the original problem is decoupled into two sub-problems: bandwidth and transmit power allocation optimization, as well as UAV trajectory optimization. We propose an efficient iterative algorithm to obtain a Karush-Kuhn-Tucker (KKT) solution via solving the two sub-problems with successive convex approximation and alternating optimization techniques. Extensive simulations are conducted to evaluate the performance and the results demonstrate that with the proposed joint design, the UAV’s energy consumption is significantly reduced, by up to 30%, and the QoE requirement for GUs can be well satisfied simultaneously.