Mission-Aware QoS for Multi-UAV-Aided Wireless Powered Sensor Networks

Multi-UAV-aided wireless powered sensor networks (WPSNs) offer an autonomous and scalable solution for large-scale IoT sensing applications, such as precision agriculture. In these systems, UAVs function as airborne charging stations, mobile data sinks and control data sources. In this paper, we advance the robustness of multi-UAV-aided WPSNs by proposing a QoS framework, called mission-aware QoS. This framework imposes two new requirements: (1) a minimum throughput guarantee for every sensor node, thereby ensuring complete delivery of all sensor readings – unlike prior approaches that rely on aggregate performance metrics and may leave individual nodes underserved; and (2) a guaranteed operational time for the system, explicitly accounting for the finite on-board energy of UAVs while ensuring successful completion of the sensing session. We formulate a new problem that incorporates these two new requirements for multi-UAV-aided WPSNs. The objective is to minimize the number of UAVs by jointly optimizing their locations, power levels, and UAV-to-node associations. We prove that this problem is NP-hard and propose a novel two-stage heuristic algorithm to solve it. Simulation results demonstrate that the proposed algorithm provides robust and efficient performance for multi-UAV-aided WPSNs.