Abstract
In this paper, we address a physical layer security (PLS) framework for the integrated sensing and semantic
communication (ISASC) system, where a multi-antenna dualfunction semantic base station serves multiple single-antenna
semantic communication users (SCUs) and monitors a malicious sensing target (MST), in the presence of a single-antenna
eavesdropper (EVE), with both the MST and EVE aiming to
wiretap information from the SCUs’ signals. To enhance PLS,
we employ joint artificial noise (AN) and dedicated sensing
signal (DSS) in addition to wiretap coding. To evaluate the
sensing accuracy, we derive the Cramer-Rao bound (CRB) as a ´
function of the communication, sensing, and AN beamforming
(BF) vectors. Subsequently, to assess the PLS level of the
ISASC system, we determine a closed-form expression for the
semantic secrecy rate (SSR). To achieve an optimal trade-off
region between these two competing objectives, we formulate
a multi-objective optimization problem for the joint design of
the BF vectors. We apply semi-definite programming, Gaussian
randomization method, and golden-section search techniques
to address this problem. Simulation results demonstrate that
the proposed scheme outperforms baseline sc