Energy-efficient Trajectory Design for UAV-enabled Wireless Communications with Latency Constraints

This paper studies a new energy-efficient unmanned
aerial vehicle (UAV)-enabled wireless communications, where the
UAV acts as a flying base station (BS) to serve the ground
users (GUs) within some predetermined latency limitations, e.g.,
requested timeout (RT). Our goal is to design the UAV trajectory
to minimize the total energy consumption while satisfying the
RT requirement from every GU, which is accomplished via two
consecutive subproblems: traveling time minimization and energy
minimization problems. Firstly, we propose two exhaustive search
and heuristic algorithms based on the traveling salesman problem
with time window (TSPTW) in order to minimize the UAV’s
traveling time without violating the GUs’ RT requirements. While
the exhaustive algorithm achieves the best performance at a high
computation cost, the heuristic algorithm achieves a trade-off
between the performance and complexity. Secondly, we minimize
the total energy consumption, for a given trajectory, via a joint
optimization of the UAV’s velocity along subsequent hops. Finally,
numerical results are presented to demonstrate the effectiveness
of our proposed algorithms. In particular, it is shown that the
proposed solutions outperform the reference in terms of both
energy consumption and outage performance.