An Effective Equivalence Model of Analyzing PLS of Multiple Eavesdroppers Facing Low-altitude Communication Systems

2025-07-08

AI Summary

In low-altitude wireless communications, physical-layer security (PLS) modeling is challenging due to uncertainty in eavesdropper location, altitude, velocity, and environmental obstructions, leading to intractable secrecy rate analysis and absence of closed-form expressions. Method: This paper proposes an equivalent security modeling framework based on reconfigurable mobile antennas. It introduces a novel single virtual eavesdropper model that maps multiple static eavesdroppers onto an equivalent physical entity equipped with a mobile antenna array, enabling derivation of a closed-form secrecy rate expression. Joint optimization of transmit beamforming and the virtual eavesdropper’s equivalent distance and antenna configuration is performed to maximize secrecy rate. Results: Simulation results validate the model’s accuracy and effectiveness, uncovering the impact mechanisms of key system parameters on PLS performance. The framework provides an analytically tractable and optimization-friendly theoretical foundation for secure low-altitude communication design.

Technology Category

• Computer Vision: Low Level & Physics-based Vision
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• Security and Privacy: Large-scale security measurements
• User Modeling, Personalization and Recommendation: User privacy protection in personalized systems
• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures

Abstract

In low-altitude wireless communications, the increased complexity of wireless channels and the uncertainty of eavesdroppers (Eves)--caused by diverse altitudes, speeds, and obstacles--pose significant challenges to physical layer security (PLS) technologies based on fixed-position antennas (FPAs), particularly in terms of beamforming capabilities and spatial efficiency. In contrast, movable antennas (MAs) offer a flexible solution by enabling channel reconstruction through antenna movement, effectively compensating for the limitations of FPAs. In this paper, we aim to derive a closed-form expression for the secrecy rate, a key metric in PLS, which is often unattainable in current studies due to the uncertainty of Eves. We construct an equivalent model that leverages the reconfigurable nature of MAs, equating the secrecy rates obtained by multiple Eves with single FPAs to those achieved by a single virtual Eve equipped with an MA array. To minimize the gap between these two types of secrecy rates, we formulate and solve an optimization problem by jointly designing the equivalent distance between the transmitter and the virtual Eve} and the antenna positions of MAs at the virtual Eve. Numerical simulations validate the effectiveness of the proposed equivalent model, offering a new perspective for PLS strategies. This work provides significant insights for network designers on how system parameters affect PLS performance.

Problem

• Analyzing PLS challenges in low-altitude wireless communications with multiple eavesdroppers
• Deriving closed-form secrecy rate expression using movable antennas
• Optimizing equivalent model to minimize secrecy rate gap

Innovation

• Equivalent model using movable antennas for security
• Optimization of virtual Eve distance and MA positions
• Closed-form secrecy rate expression for PLS