UDADT : An Energy‐ and Delay‐Aware Trajectory Planning for UAV ‐Assisted Wireless Sensor Networks

This paper deals with delay and energy efficiency in unmanned aerial vehicle (UAV)‐assisted wireless sensor networks, where a UAV follows a tour to aggregate buffered data from cluster heads via direct communication. We first propose a heuristic scheme, called “UAV‐assisted Data Aggregation with Arched and Diagonal Trajectories (UDADT),” to design the UAV trajectory. Toward this goal, the network area is partitioned with virtual concentric circles and virtual lines to identify candidate UAV hovering points. Two types of UAV trajectories are considered, including the arched trajectory and diagonal trajectory. Subsequently, the UDADT algorithm is extended to the “Modified UDADT (M‐UDADT)” scheme to facilitate its implementation while further improving network performance. In addition, the minimum transmission power required by nodes is analytically derived for the proposed schemes. Finally, a comprehensive performance evaluation is conducted to investigate the proposed heuristic algorithms in comparison with an optimal scheme as a benchmark. Numerical results confirm the efficiency of the proposed approach in terms of delay and energy, especially since the trajectory delay generated by M‐UDADT is close to the optimal bound.