Movable Frequency Diverse Array for Wireless Communication Security

TL;DR

This paper introduces a movable frequency diverse array (MFDA) that dynamically adjusts antenna positions to improve wireless communication security, especially under strict frequency constraints, outperforming traditional phased arrays and fixed FDA systems.

Contribution

The paper proposes a novel movable FDA technology with joint optimization of antenna parameters, enhancing physical layer security beyond existing FDA and phased array methods.

Findings

MFDA significantly improves secrecy capacity over traditional schemes.

Dynamic antenna positioning enhances security when frequency constraints are strict.

Simulation results confirm the effectiveness of the proposed optimization approach.

Abstract

Frequency diverse array (FDA) is a promising antenna technology to achieve physical layer security by varying the frequency of each antenna at the transmitter. However, when the channels of the legitimate user and eavesdropper are highly correlated, FDA is limited by the frequency constraint and cannot provide satisfactory security performance. In this paper, we propose a novel movable FDA (MFDA) antenna technology where the positions of antennas can be dynamically adjusted in a given finite region. Specifically, we aim to maximize the secrecy capacity by jointly optimizing the antenna beamforming vector, antenna frequency vector and antenna position vector. To solve this non-convex optimization problem with coupled variables, we develop a two-stage alternating optimization (AO) algorithm based on block successive upper-bound minimization (BSUM) method. Moreover, to evaluate the security performance provided by MFDA, we introduce two benchmark schemes, i.e., phased array (PA) and FDA. Simulation results demonstrate that MFDA can significantly enhance security performance compared to PA and FDA. In particular, when the frequency constraint is strict, MFDA can further increase the secrecy capacity by adjusting the positions of antennas instead of the frequencies.