Secrecy Transmission in Large-Scale UAV-Enabled Wireless Networks

TL;DR

This paper analyzes the secrecy transmission performance of large-scale UAV-enabled wireless networks with ground eavesdroppers, optimizing system parameters and employing guard zones to enhance security and capacity.

Contribution

It provides a mathematical framework for secrecy performance analysis and introduces a guard zone technique to improve secrecy capacity in UAV networks.

Findings

Secrecy guard zones significantly improve secrecy transmission capacity.

Optimal guard zone radius decreases as UAV and eavesdropper densities increase.

Mathematically tractable expressions for secrecy metrics are derived.

Abstract

This paper considers the secrecy transmission in a large-scale unmanned aerial vehicle (UAV)-enabled wireless network, in which a set of UAVs in the sky transmit confidential information to their respective legitimate receivers on the ground, in the presence of another set of randomly distributed suspicious ground eavesdroppers. We assume that the horizontal locations of legitimate receivers and eavesdroppers are distributed as two independent homogeneous Possion point processes (PPPs), and each of the UAVs is positioned exactly above its corresponding legitimate receiver for efficient secrecy communication. Furthermore, we consider an elevation-angle-dependent line-of-sight (LoS)/non-LoS (NLoS) path-loss model for air-to-ground (A2G) wireless channels and employ the wiretap code for secrecy transmission. Under such setups, we first characterize the secrecy communication performance (in terms of the connection probability, secrecy outage probability, and secrecy transmission capacity) in mathematically tractable forms, and accordingly optimize the system configurations (i.e., the wiretap code rates and UAV positioning altitude) to maximize the secrecy transmission capacity, subject to a maximum secrecy outage probability constraint. Next, we propose to use the secrecy guard zone technique for further secrecy protection, and analyze the correspondingly achieved secrecy communication performance. Finally, we present numerical results to validate the theoretical analysis. It is shown that the employment of secrecy guard zone significantly improves the secrecy transmission capacity of this network, and the desirable guard zone radius generally decreases monotonically as the UAVs' and/or the eavesdroppers' densities increase.