Towed Movable Antenna (ToMA) Array for Ultra Secure Airborne Communications

2025-08-02

AI Summary

To address the physical-layer security bottleneck in airborne communication systems under eavesdropping threats, this paper proposes a novel architecture based on a towed, reconfigurable antenna array: multiple UAVs cooperatively drag distributed sub-arrays mounted on flexible tethers, enabling three-dimensional dynamic reconfiguration around a central platform. This design overcomes the aperture limitation of conventional fixed arrays by optimizing antenna position vectors to reduce channel correlation between legitimate users and eavesdroppers, thereby enhancing spatial resolution. Furthermore, zero-forcing beamforming is integrated with a low-complexity alternating optimization algorithm operating on the Riemannian manifold to jointly optimize antenna placement and beamforming weights. Simulation results demonstrate that, under line-of-sight-dominant conditions with eavesdroppers located in proximity to legitimate users, the proposed scheme significantly improves the ergodic achievable rate of the legitimate user and substantially increases the secrecy capacity.

Technology Category

• Search and Optimization: Algorithm Configuration
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Machine Learning: Hardware-aware ML

Application Category

• Security and Privacy: Large-scale security measurements
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

This paper proposes a novel towed movable antenna (ToMA) array architecture to enhance the physical layer security of airborne communication systems. Unlike conventional onboard arrays with fixed-position antennas (FPAs), the ToMA array employs multiple subarrays mounted on flexible cables and towed by distributed drones, enabling agile deployment in three-dimensional (3D) space surrounding the central aircraft. This design significantly enlarges the effective array aperture and allows dynamic geometry reconfiguration, offering superior spatial resolution and beamforming flexibility. We consider a secure transmission scenario where an airborne transmitter communicates with multiple legitimate users in the presence of potential eavesdroppers. To ensure security, zero-forcing beamforming is employed to nullify signal leakage toward eavesdroppers. Based on the statistical distributions of locations of users and eavesdroppers, the antenna position vector (APV) of the ToMA array is optimized to maximize the users' ergodic achievable rate. Analytical results for the case of a single user and a single eavesdropper reveal the optimal APV structure that minimizes their channel correlation. For the general multiuser scenario, we develop a low-complexity alternating optimization algorithm by leveraging Riemannian manifold optimization. Simulation results confirm that the proposed ToMA array achieves significant performance gains over conventional onboard FPA arrays, especially in scenarios where eavesdroppers are closely located to users under line-of-sight (LoS)-dominant channels.

Problem

• Enhance airborne communication security via movable antenna arrays
• Optimize antenna positions to maximize legitimate users' data rates
• Reduce signal leakage to eavesdroppers using dynamic beamforming techniques

Innovation

• Towed movable antenna array for 3D deployment
• Zero-forcing beamforming to prevent eavesdropping
• Optimized antenna position vector for secure communication