Joint Secure Communication and Radar Beamforming: A Secrecy-Estimation Rate-Based Design

TL;DR

This paper develops a beamforming design for dual-function radar-communication systems that maximizes secrecy rate while ensuring radar estimation performance, incorporating artificial noise and robustness to imperfect channel information.

Contribution

It introduces closed-form solutions for secrecy rate maximization in DFRC systems, including robust designs under imperfect CSI and artificial noise strategies.

Findings

Closed-form beamforming solutions for secrecy rate maximization.

Artificial noise improves security and robustness.

Robust design effectively handles channel uncertainties.

Abstract

This paper considers transmit beamforming in dual-function radar-communication (DFRC) system, where a DFRC transmitter simultaneously communicates with a communication user and detects a malicious target with the same waveform. Since the waveform is embedded with information, the information is risked to be intercepted by the target. To address this problem, physical-layer security technique is exploited. By using secrecy rate and estimation rate as performance measure for communication and radar, respectively, three secrecy rate maximization (SRM) problems are formulated, including the SRM with and without artificial noise (AN), and robust SRM. For the SRM beamforming, we prove that the optimal beamformer can be computed in closed form. For the AN-aided SRM, by leveraging alternating optimization similar closed-form solution is obtained for the beamformer and the AN covariance matrix. Finally, the imperfect CSI of the target is also considered under the premise of a moment-based random phase-error model on the direction of arrival at the target. Simulation results demonstrate the efficacy and robustness of the proposed designs.