Handover-Aware Trajectory Optimization for Cellular-Connected UAV

TL;DR

This paper proposes a trajectory optimization method for cellular-connected UAVs to minimize handovers while ensuring communication quality and mission time constraints, using graph theory and Lagrangian relaxation.

Contribution

It introduces a novel optimization framework for UAV trajectory planning that reduces handovers, addressing practical communication issues in cellular-connected UAV missions.

Findings

The proposed algorithm effectively reduces the number of handovers.

Numerical results demonstrate improved communication stability.

The method achieves near-optimal solutions in polynomial time.

Abstract

In this letter, we study a cellular-connected unmanned aerial vehicle (UAV) which aims to complete a mission of flying between two pre-determined locations while maintaining satisfactory communication quality with the ground base stations (GBSs). Due to the potentially long distance of the UAV's flight, frequent handovers may be incurred among different GBSs, which leads to various practical issues such as large delay and synchronization overhead. To address this problem, we investigate the trajectory optimization of the UAV to minimize the number of GBS handovers during the flight, subject to a communication quality constraint and a maximum mission completion time constraint. Although this problem is non-convex and difficult to solve, we derive useful structures of the optimal solution, based on which we propose an efficient algorithm based on graph theory and Lagrangian relaxation for finding a high-quality suboptimal solution in polynomial time. Numerical results validate the effectiveness of our proposed trajectory design.