Securing UAV Communications via Joint Trajectory and Power Control (1801.06682v2)

Abstract: Unmanned aerial vehicle (UAV) communication is anticipated to be widely applied in the forthcoming fifth-generation (5G) wireless networks, due to its many advantages such as low cost, high mobility, and on-demand deployment. However, the broadcast and line-of-sight (LoS) nature of air-to-ground wireless channels gives rise to a new challenge on how to realize secure UAV communications with the destined nodes on the ground. This paper aims to tackle this challenge by applying the physical layer security technique. We consider both the downlink and uplink UAV communications with a ground node, namely UAV-to-ground (U2G) and ground-to-UAV (G2U) communications, respectively, subject to a potential eavesdropper on the ground. In contrast to the existing literature on wireless physical layer security only with ground nodes at fixed or quasi-static locations, we exploit the high mobility of the UAV to proactively establish favorable and degraded channels for the legitimate and eavesdropping links, respectively, via its trajectory design. We formulate new problems to maximize the average secrecy rates of the U2G and G2U transmissions, respectively, by jointly optimizing the UAV's trajectory and the transmit power of the legitimate transmitter over a given flight period of the UAV. Although the formulated problems are non-convex, we propose iterative algorithms to solve them efficiently by applying the block coordinate descent and successive convex optimization methods. Specifically, the transmit power and UAV trajectory are each optimized with the other being fixed in an alternating manner, until the algorithms converge. Simulation results show that the proposed algorithms can improve the secrecy rates for both U2G and G2U communications, as compared to other benchmark schemes without power control and/or trajectory optimization.

• The paper introduces a joint optimization framework for UAV trajectory and power control to enhance secrecy rates against eavesdropping.
• It employs iterative algorithms using block coordinate descent and successive convex optimization to tackle non-convex secrecy rate maximization challenges.
• Simulation results demonstrate significant improvements in secrecy rates for both UAV-to-ground and ground-to-UAV links compared to conventional methods.

Securing UAV Communications via Joint Trajectory and Power Control

The paper "Securing UAV Communications via Joint Trajectory and Power Control" by Guangchi Zhang et al. addresses the challenge of securing UAV communications in air-to-ground networks. With the impending integration of UAVs into 5G infrastructures, securing these communications has become vital due to the inherent vulnerabilities in broadcast and LoS channels between UAVs and terrestrial nodes, which can be susceptible to eavesdropping.

Problem Overview

The paper focuses on enhancing physical layer security through simultaneous trajectory and power control optimization of UAVs. Unlike traditional static node models, the authors leverage UAV mobility to optimize communication channels favorably for legitimate users while degrading channels for potential eavesdroppers. This joint optimization approach is applied to both UAV-to-ground (U2G) and ground-to-UAV (G2U) communications, which are subject to non-convex secrecy rate maximization challenges.

Methodology

The authors develop mathematical models to jointly maximize the average secrecy rates of U2G and G2U links. This involves optimizing the UAV’s trajectory and transmit power over a designated flight duration. The problem formulation accounts for non-convex constraints, which are addressed using iterative algorithms based on block coordinate descent and successive convex optimization. The trajectory optimization and power control are performed in an alternating manner until convergence.

Numerical Results

Simulation results illustrate that the proposed algorithms significantly enhance secrecy rates for both U2G and G2U communications compared to benchmark schemes that do not employ trajectory optimization and/or power control. Notably, for the U2G scenario, the importance of joint optimization becomes evident as mobility allows modification of the relative channels, solely attainable for the U2G case. In contrast, T-OPT-Without-PC displayed diminished efficacy in some scenarios, highlighting the pivotal role of combining trajectory design with power adaptation.

Implications and Future Directions

The findings underscore the necessity of adaptive UAV trajectory and power control to tackle the unique security challenges posed by UAV-enable networks. The flexible establishment of UAVs in optimum positions mitigates eavesdropping risks while maintaining communication integrity, making this approach viable for future wireless networks with UAV components. Moreover, the paper lays a theoretical foundation for subsequent developments in secure UAV communication protocols, suggesting further exploration in adaptive real-time algorithms and multi-UAV scenarios for diverse deployment frameworks.

In advancing UAV communications in the 5G era, this research offers practical insights into leveraging UAV mobility for secure communications, providing a blueprint for future studies in optimizing and securing next-generation aerial communication networks.