Two Birds With One Stone: Beamforming Design for Target Sensing and Proactive Eavesdropping

TL;DR

This paper proposes a beamforming design that enables a base station to simultaneously perform target sensing and proactive eavesdropping, optimizing waveform strategies to enhance eavesdropping and sensing performance.

Contribution

It introduces a joint beamforming optimization framework for simultaneous target sensing and proactive eavesdropping, using relaxation techniques to solve complex non-convex problems.

Findings

The proposed algorithm effectively achieves both PE and TS.

Joint design outperforms separate optimization approaches.

Scenario analysis shows robustness when eavesdropping channels are stronger.

Abstract

This work studies the beamforming design in the joint proactive eavesdropping (PE) and target sensing (TS) systems. The base station (BS) wiretaps the information transmitted by the illegal transmitter and sends the waveform for TS. The shared waveform also serves as artificial noise to interfere with the illegal receiver, thereby achieving successful PE.We firstly optimize the transmitting beampattern of the BS only to maximize the eavesdropping rate or only to minimize the Cram{\'{e}}r-Rao bound, respectively. Then, the joint design of PE and TS is investigated by formulating the PE-centric, the TS-centric, and the normalized weighted optimization problems. The formulated problems are solved by the semi-definite relaxation technique and the sequential rank-one constraint relaxation method to address the complexity of the original problem. Furthermore, the scenario in which the quality of the eavesdropping channel is stronger than that of the illegal channel is considered. Numerical results demonstrate that the proposed algorithm can effectively realize PE and TS simultaneously.