Secure Wireless Communication for Correlated Legitimate User and Eavesdropper Channels via Movable-Antenna Enhanced...

Area of Science:

• Wireless Communications
• Information Security
• Signal Processing

Background:

• Physical-layer (PHY) security is crucial for secure wireless communications but is challenged by channel coupling when legitimate users (LU) and eavesdroppers (Eve) are close.
• Frequency Diverse Array (FDA) mitigates coupling using frequency offsets but lacks spatial control.
• Movable Antenna (MA) technology offers dynamic spatial adjustments to further decouple channels.

Purpose of the Study:

• To propose and evaluate a novel Movable Antenna-Frequency Diverse Array (MA-FDA) approach for enhancing PHY security.
• To maximize the achievable secrecy rate by jointly optimizing antenna positions, FDA frequency offsets, and beamformer.
• To address the non-convex optimization problem with coupled variables under practical constraints.

Main Methods:

• Joint optimization of antenna positions, FDA frequency offsets, and beamformer.
• Alternating Optimization (AO) method for parameter updates.
• Projected Gradient Ascent (PGA) and Block Successive Upper-Bound Minimization (BSUM) for subproblem solutions.

Main Results:

• The proposed MA-FDA approach demonstrates a higher achievable secrecy rate compared to conventional phased array (PA) and fixed-position antenna (FPA) schemes.
• The joint optimization effectively manages antenna positions, frequency offsets, and beamforming for improved security.
• Simulation results validate the effectiveness of the MA-FDA strategy in enhancing PHY security.

Conclusions:

• The MA-FDA approach provides a comprehensive solution for improving PHY security, especially in scenarios with close-proximity users and eavesdroppers.
• Dynamic adjustment of antenna positions and FDA frequency offsets are key to overcoming channel coupling limitations.
• This novel technique offers a significant advancement in securing wireless communications through advanced antenna and frequency management.