Backhaul-Aware Resource Allocation and Optimum Placement for UAV-Assisted Wireless Communication Network

Yishi Xue,Hongbo Zhu,Bo Xu,Wenchao Xia,Jun Zhang

doi:10.3390/electronics9091397

Yishi Xue, Hongbo Zhu + Show 3 more

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https://doi.org/10.3390/electronics9091397

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Abstract

Driven by its agile maneuverability and deployment, the unmanned aerial vehicle (UAV) becomes a potential enabler of the terrestrial networks. In this paper, we consider downlink communications in a UAV-assisted wireless communication network, where a multi-antenna UAV assists the ground base station (GBS) to forward signals to multiple user equipments (UEs). The UAV is associated with the GBS through in-band wireless backhaul, which shares the spectrum resource with the access links between UEs and the UAV. The optimization problem is formulated to maximize the downlink ergodic sum-rate by jointly optimizing UAV placement, spectrum resource allocation and transmit power matrix of the UAV. The deterministic equivalents of UE’s achievable rate and backhaul capacity are first derived by utilizing large-dimensional random matrix theory, in which, only the slowly varying large-scale channel state information is required. An approximation problem of the joint optimization problem is then introduced based on the deterministic equivalents. Finally, an algorithm is proposed to obtain the optimal solution of the approximate problem. Simulation results are provided to validate the accuracy of the deterministic equivalents, and the effectiveness of the proposed method.

Highlights

Unmanned aerial vehicles (UAVs) has been widely investigated and applied to provide seamless coverage and capacity enhancement in wireless communication systems [1,2,3]
unmanned aerial vehicle (UAV)-assisted wireless communication network where a ground base station (GBS) is located at the origin with N = 12 antennas
We considered a UAV-assisted wireless communication network where a multi-antenna UAV utilized as a remote relay, assisted the GBS to forward signals for user equipments (UEs) in remote areas outside the coverage of the GBS

Summary

Introduction

Unmanned aerial vehicles (UAVs) has been widely investigated and applied to provide seamless coverage and capacity enhancement in wireless communication systems [1,2,3]. Deployed as aerial base stations or mounted with access points, UAVs can provide flexible and on-demand services to ground users dynamically by leveraging its agile mobility and maneuverability. UAVs can be exploited to load traffic in temporary or unexpected circumstances when the ground base stations (GBSs) are congested or broken. UAVs can assist the GBSs to relay signals to remote users who are out of the coverage provided by terrestrial infrastructure [4]. Differing from the GBSs, the lack of fixed backhaul link for UAVs has emerged as a challenge in UAV-assisted wireless communication network, which needs to be further investigated [6]

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