Movable Antenna Empowered Covert Dual-Functional Radar-Communication

TL;DR

This paper introduces a movable antenna-enabled dual-functional radar-communication system that optimizes security and performance by jointly designing beamforming, antenna placement, and detection strategies, using advanced optimization algorithms.

Contribution

It proposes a novel framework leveraging movable antennas for secure dual-functional radar-communication, with new algorithms for both non-colluding and colluding eavesdropper scenarios.

Findings

Significant increase in covert sum rate achieved.

Enhanced security and balanced radar-communication performance.

Efficient optimization algorithms outperform benchmarks.

Abstract

Movable antenna (MA) has emerged as a promising technology to flexibly reconfigure wireless channels by adjusting antenna placement. In this paper, we study a secured dual-functional radar-communication (DFRC) system aided by movable antennas. To enhance the communication security, we aim to maximize the achievable sum rate by jointly optimizing the transmitter beamforming vectors, receiving filter, and antenna placement, subject to radar signal-to-noise ratio (SINR) and transmission covertness constraints. We consider multiple Willies operating in both non-colluding and colluding modes. For noncolluding Willies, we first employ a Lagrangian dual transformation procedure to reformulate the challenging optimization problem into a more tractable form. Subsequently, we develop an efficient block coordinate descent (BCD) algorithm that integrates semidefinite relaxation (SDR), projected gradient descent (PGD), Dinkelbach transformation, and successive convex approximation (SCA) techniques to tackle the resulting problem. For colluding Willies, we first derive the minimum detection error probability (DEP) by characterizing the optimal detection statistic, which is proven to follow the generalized Erlang distribution. Then, we develop a minimum mean square error (MMSE)-based algorithm to address the colluding detection problem. We further provide a comprehensive complexity analysis on the unified design framework. Simulation results demonstrate that the proposed method can significantly improve the covert sum rate, and achieve a superior balance between communication and radar performance compared with existing benchmark schemes.