Sensing-then-transmit: A two-phase secure ISAC framework
Author Identifier (ORCID)
Abstract
This paper develops a two-phase secure integrated sensing and communication (ISAC) framework, where a dual-function transmitter (Alice) detects the presence of a potential eavesdropper (Eve) as a sensing target in the first phase. In the second phase, Alice adapts her secure transmission strategy based on the sensing outcome of the first phase. A distinct aspect of our developed two-phase framework is the derivation of the overall effective secrecy rate across both phases. In our proposed framework, for system design, we aim to maximize the overall effective secrecy rate subject to Alice’s average transmit power over the two phases remaining below a predetermined threshold. To address the resulting nonconvex design problem, an algorithm based on the improved twin-delayed deep deterministic policy gradient (TD3) is proposed. In addition, two low-complexity solutions are developed to simplify the design of the transmit beamforming in the first phase. Our numerical results show that the proposed two-phase secure ISAC framework significantly enhances the secrecy rate compared to a conventional physical layer security (PLS) system if Eve is present with a low probability. This explicitly shows the effectiveness of exploiting sensing for enhancing the security of wireless communications.
Keywords
ISAC, physical layer security, secrecy rate, sensing-aided communication, two-phase framework
Document Type
Journal Article
Date of Publication
1-1-2026
E-ISSN
15582248
ISSN
15361276
Volume
25
Publication Title
IEEE Transactions on Wireless Communications
Publisher
IEEE
School
School of Science
Copyright
subscription content
First Page
22261
Last Page
22274
Recommended Citation
Zhang, Q., Yan, S., Zhou, X., Shu, F., Ng, D. W. K., & Schober, R. (2026). Sensing-then-transmit: A two-phase secure ISAC framework. IEEE Transactions on Wireless Communications, 25, 22261–22274. https://doi.org/10.1109/TWC.2026.3725734