Physical Layer Security in UAV Systems: Challenges and Opportunities (1909.06785v1)

Abstract: Unmanned aerial vehicle (UAV) wireless communications have experienced an upsurge of interest in both military and civilian applications, due to its high mobility, low cost, on-demand deployment, and inherent line-of-sight (LoS) air-to-ground channels. However, these benefits also make UAV wireless communication systems vulnerable to malicious eavesdropping attacks. In this article, we aim to examine the physical layer security issues in UAV systems. In particular, passive and active eavesdroppings are two primary attacks in UAV systems. We provide an overview on emerging techniques, such as trajectory design, resource allocation, and cooperative UAVs, to fight against both types of eavesdroppings in UAV wireless communication systems. Moreover, the applications of non-orthogonal multiple access, multiple-input and multiple-output, and millimeter wave in UAV systems are also proposed to improve the system spectral efficiency and to guarantee security simultaneously. Finally, we discuss some potential research directions and challenges in terms of physical layer security in UAV systems.

• The paper examines physical layer security challenges and opportunities in UAV systems, highlighting eavesdropping threats and the need for novel security measures.
• It discusses UAV-centric PLS techniques, such as optimizing trajectory and resource allocation and employing multi-UAV cooperative strategies.
• Advanced techniques like NOMA, 3D beamforming, and mmWave communications can further enhance physical layer security by exploiting spatial and channel properties.
• meta_description
• Explore challenges and opportunities for physical layer security in UAV communication systems, examining eavesdropping threats and discussing advanced PLS techniques.
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• Physical Layer Security in UAV Systems

Overview of Physical Layer Security in UAV Systems

The paper presents a thorough examination of physical layer security (PLS) challenges and opportunities within unmanned aerial vehicle (UAV) communication systems. Given the increasing application of UAVs in diverse military and civilian sectors, due to advantages like high maneuverability, low operational cost, and on-demand deployment, understanding and addressing security vulnerabilities in UAV networks is of substantial interest. UAV communication systems are particularly susceptible to eavesdropping due to their inherent line-of-sight (LoS) channels, which mandate novel security measures to protect sensitive information.

Security Challenges and Eavesdropping in UAV Networks

The paper categorizes eavesdropping threats into passive and active scenarios. Passive eavesdroppers silently intercept transmissions, a threat exacerbated by limited positional intelligence about the eavesdroppers. Comparatively, active eavesdroppers engage more aggressively by jamming transmissions to weaken legitimate communication pathways. The paper explores varied levels of eavesdropper positional information: fully known, partially known, and unknown, each presenting unique challenges for PLS strategies.

PLS Techniques for UAV Systems

The authors discuss the integration of UAV-centric resources like tactical trajectory adjustments and resource allocations to bolster communication security. By optimizing UAV paths, transmissions can strategically avoid the coverage regions of potential eavesdroppers.

• Joint Design Approaches: The integration of trajectory and resource allocation design emerges as a robust approach to maximizing spectral efficiency while ensuring secure transmission, leveraging the spatio-temporal flexibility of UAVs.
• Robust Design for Partial Information: When only partial location data of eavesdroppers is available, robust design measures account for worst-case scenarios. Such techniques ensure that the UAV-based systems remain resilient to uncertainties in eavesdropper positions.
• Multi-UAV Cooperative Strategies: The deployment of multiple UAVs in coordinated efforts is highlighted as a promising strategy to enhance PLS. This encompasses CoMP techniques, where multiple UAVs utilize combined resources for secure signal transmission while potentially jamming eavesdroppers.

Advanced Techniques for Improved PLS

The paper further explores advanced communication techniques, including non-orthogonal multiple access (NOMA), 3D beamforming, and millimeter-wave (mmWave) communications, to enhance the PLS in UAV systems.

• NOMA: Demonstrated through simulation, NOMA can outperform traditional orthogonal multiple access in providing dual-layer communications with a higher tolerance to eavesdropping.
• 3D Beamforming: Exploitating the 3D spatial properties of UAV-to-ground communications, this method enhances the directivity of signals towards legitimate receivers, reducing eavesdropping opportunities.
• mmWave Technology: By utilizing the high-frequency bands, mmWave communications capitalize on LoS channel properties for enhanced directionality and bandwidth, thus reducing interception risks.

Implications and Future Directions

The implications of this paper are multifaceted, affecting both theoretical and practical applications of UAVs in secure communications. The paper delineates several open issues and research directions, such as the need for realistic channel modeling, advanced pilot contamination countermeasures, and the management of limited onboard resources. These areas are critical for the deployment of robust, secure UAV communication networks under varied environmental and operational conditions.

Overall, the paper lays a vital groundwork for future exploration into securing UAV networks, advising on the potential of integrating advanced communication technologies with strategic resource allocation and trajectory planning to overcome the inherent vulnerabilities of air-to-ground communication channels. The exploration of PLS in UAV systems as presented is crucial for advancing secure communications in increasingly autonomous aerial systems.