Joint UAV Hovering Altitude and Power Control for Space-Air-Ground IoT Networks

Unmanned aerial vehicles (UAVs) have been widely used in both military and civilian applications. Equipped with diverse communication payloads, UAVs cooperating with satellites and base stations constitute a space-air-ground three-tier heterogeneous network, which are beneficial in terms of both providing the seamless coverage as well as of improving the capacity for increasingly prosperous Internet of Things networks. However, cross-tier interference may be inevitable among these tightly embraced heterogeneous networks when sharing the same spectrum. The power association problem in satellite, UAV and macrocell three-tier networks becomes a critical issue. In this paper, we propose a two-stage joint hovering altitude and power control solution for the resource allocation problem in UAV networks considering the inevitable cross-tier interference from space-air-ground heterogeneous networks. Furthermore, Lagrange dual decomposition and concave-convex procedure method are used to solve this problem, followed by a low-complexity greedy search algorithm. Finally, simulation results show the effectiveness of our proposed two-stage joint optimization algorithm in terms of UAV network's total throughput.

I. Introduction

Given the substantial success of unmanned aerial vehicles (UAVs) in surveillance and monitoring tasks, it has become vitally important to bring drones into wireless communications considering their low cost, fast deployment, fully controllable mobility as well as the line of sight (LOS) communication links. These drones are usually equipped with diverse payloads for receiving, processing and transiting signals, which can be viewed as the aerial mobile base station constituting UAV communication networks [1], [2].