Joint Maneuver and Beamwidth Optimization for UAV-Enabled Multicasting

Na Tang,Xiaobing Yuan,Baoqing Li,Hongying Tang

doi:10.1109/access.2019.2947031

Abstract

Unmanned aerial vehicles (UAVs)-assisted communications have been an essential complement of conventional wireless networks. In this paper, we consider a UAV-enabled multicasting system, where a UAV with a directional antenna of adjustable beamwidth is employed to disseminate a common file to a group of ground users. By minimizing the mission completion time, we investigate how beamwidth control would affect the UAV's three-dimensional (3D) location/trajectory. First, we consider the quasi-stationary UAV scenario, where the UAV is deployed at a static location. In this case, we jointly optimize the 3D UAV location and antenna beamwidth under the practical constraints on the UAV's altitude and beamwidth, while ensuring that all users are covered by the main lobe of the UAV antenna. Although this problem is nonconvex, its global optimality can be obtained by using a two-step algorithm, where semi-closed solutions of the 3D location and beamwidth are derived. Next, in the mobile UAV scenario, a joint 3D UAV trajectory and beamwidth design is proposed, additionally constrained by the horizontal and vertical speed. To tackle this nonconvex problem, we develop an iterative optimization algorithm based on successive convex approximation techniques, which updates the 3D trajectory and beamwidth simultaneously in each iteration. Numerical results demonstrate the effectiveness of the proposed design as compared to benchmark schemes.

Highlights

Wireless communications enabled by unmanned aerial vehicles (UAVs) have been envisioned as a promising technology in military, civilian and commercial applications [1], [2]
JOINT 3D LOCATION AND ANTENNA BEAMWIDTH OPTIMIZATION FOR QUASI-STATIONARY UAV SCENARIO we propose an efficient algorithm for solving problem (14), in which the optimal solution can be obtained in two steps
It can be seen that when τ ∗ < τ1 m, i.e., case 1, the UAV can fly at hmin with min

Summary

Introduction

Wireless communications enabled by unmanned aerial vehicles (UAVs) have been envisioned as a promising technology in military, civilian and commercial applications [1], [2]. Compared to traditional terrestrial communications, UAV systems provide several key advantages including the ability of on-demand deployment, line-of-sight (LoS) dominant UAV-ground channels, and additional degree-offreedom (DoF) in three-dimensional (3D) space. The associate editor coordinating the review of this manuscript and approving it for publication was Juan Liu. aerial base stations (BSs) to provide ubiquitous wireless coverage for ground users. Aerial base stations (BSs) to provide ubiquitous wireless coverage for ground users Along this line, the UAV location in two-dimensional (2D) or 3D space is optimized for various objectives, including outage probability [3], coverage area [4], [5], the number of served users [6], [7], and the number of required UAVs [8], as well as communication throughput/power [7], [9]. Based on a LoS map approach, Chen and Gesbert [9] optimize the UAV position to maximize the end-to-end throughput for a relay system

Objectives

Results

Conclusion