Design and Performance Analysis of UAV-Enabled Massive IoT Networks With Circular UAV Trajectory

Abstract

In this work we study massive Internet-of-Things (IoT) networks with single or multiple unmanned aerial vehicle (UAV) base stations (BSs) with circular trajectory to serve a large number of users independently and uniformly distributed in a disk region under the line-of-sight (LOS) channel. For single-UAV systems, a low-complexity angle-based user scheduling is proposed. For multi-UAV systems, a user scheduling scheme is developed where the users are assigned to UAVs based on their radii and then scheduled through the angle-based scheme. For both systems, we derive closed-form expressions of the upper bounds of the average achievable rate as the number of users grows to infinity. We further prove that the performance of the proposed user scheduling schemes are asymptotically optimal. The theoretical results facilitate efficient optimization of the UAV trajectory radii and reveal scaling laws of the system performance, and are validated through numerical simulations.