Robust Trajectory and Power Control for Cognitive UAV Secrecy Communication

Ying Gao,Xiaobing Yuan,Hongying Tang,Baoqing Li

doi:10.1109/access.2020.2979193

Abstract

This paper investigates the physical layer security issue in an unmanned aerial vehicle (UAV) aided cognitive radio network. Specially, a UAV operates as an aerial secondary transmitter to serve a ground secondary receiver (SR) by sharing the licensed wireless spectrum assigned to primary terrestrial communication networks, and in the meantime multiple eavesdroppers (Eves) try to wiretap the legitimate UAV-to-SR link. Under the assumption that the location formation of the Eves is imperfect, we jointly optimize the robust trajectory and transmit power of the UAV over a finite flight period to maximize the SR's average worst-case secrecy rate, while controlling the co-channel interference imposed on the primary receivers (PRs) below a tolerable level. The design is formulated as a non-convex semi-infinite optimization problem that is challenging to be optimally solved. To deal with it, we first prove that the considered problem can be simplified as a more tractable one, which resolves the location uncertainties of the Eves without the aid of $\mathcal S$ -Procedure adopted in conventional methods. After that, an efficient iterative algorithm based on successive convex approximation (SCA) is developed to obtain a locally optimal solution. Numerical simulations are provided to demonstrate the effectiveness of our proposed algorithm and offer important system design insights.

Highlights

For the past few years, unmanned aerial vehicles (UAVs) have found widespread promising applications in the field of wireless communications due to their several advantages, such as highly controllable mobility, the ability of on-demand deployment, and line-of-sight (LoS) air-to-ground links [1]
Our target is to maximize the secondary receiver (SR)’s average worst-case secrecy rate through jointly designing the UAV’s transmit power and trajectory over a finite flight duration with predetermined initial and final locations, subject to the mobility and transmit power constraints of the UAV, and the interference temperature (IT) constraints at the primary receivers (PRs)
4 In Algorithm 1 proposed in Section III-C, we show that Zr is the solution obtained from the (r − 1)-th iteration, and Z 0 stands for the initial point

Summary

Introduction

For the past few years, unmanned aerial vehicles (UAVs) have found widespread promising applications in the field of wireless communications due to their several advantages, such as highly controllable mobility, the ability of on-demand deployment, and line-of-sight (LoS) air-to-ground links [1]. UAVs can be employed as aerial base stations (BSs) [2] to provide wireless service for a set of ground users, mobile relays [3] to deliver the source data to a remote destination node, or mobile data collectors [4] for wireless sensor networks. To fully exploit the high mobility of UAVs, the other type considers the application scenarios where UAVs are employed as mobile BSs/relays/access points/energy transmitters, whose locations over time (i.e., trajectories) can be properly designed to improve the communication performance. A trajectory optimization problem is studied in [11] for completion time minimization in UAV-enabled multicasting. For a rotary-wing UAV-enabled wireless communication system, the work [13] studies the joint optimization of UAV trajectory, communication scheduling and mission completion time to minimize the UAV energy

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Results

Conclusion