Beamforming Optimization for Integrated Sensing and Communication Systems Against Eavesdropping and Malicious Jamming

Abstract

This paper investigates secure beamforming designs for integrated sensing and communication (ISAC) systems, where a base station (BS) provides downlink and uplink communication services while performing target sensing, under both passive eavesdropping and active malicious jamming. To address these threats, a comprehensive secure design is developed for the full transceiver link. First, we formulate an optimization problem to maximize the system secrecy rate (SR) with the integrated sidelobe-to-mainlobe ratio (ISMR) constraint for sensing performance, via the joint design of transmit beamforming and artificial noise (AN) injection for downlink ISAC systems. The non-convex problem is efficiently solved using successive convex approximation (SCA) and semidefinite relaxation (SDR) techniques. Then, we develop a robust receive beamforming scheme based on the multi-output linearly constrained minimum variance (MO-LCMV) criterion and derive its closed-form optimal solution to achieve reliable reception of communication and sensing signals as well as effective jamming suppression for uplink ISAC systems. Finally, numerical results verify that the proposed designs outperform conventional benchmark schemes by achieving superior secrecy rate for downlink ISAC systems while ensuring sensing performance, and effective jamming suppression for uplink ISAC systems.