Integrated sensing and covert communications with RIS adaptive and non-adaptive modes
Abstract
In this work, we consider an integrated sensing and covert communication (ISACC) system with a finite blocklength L aided by a reconfigurable intelligent surface (RIS) with N elements. Specifically, with the aid of RIS, a transmitter Alice is to sense the potential existence of a target, and she is also probabilistically trying to send information to a receiver Bob covertly (i.e., trying to hide her transmissions from a warden Willie). Meanwhile, Willie is to detect whether Alice is sensing the target only or conducting ISACC. We consider two RIS operation modes, i.e., a non-adaptive mode, where RIS employs a common beamforming vector regardless of whether Alice performs sensing-only or ISACC transmissions, and an adaptive mode, where RIS dynamically switches between two beamforming vectors tailored to the transmission type. For each mode, we formulate and solve an optimization problem that jointly determines Alice’s power allocation fraction ρ for covert information signals and RIS beamforming vectors to maximize the effective covert communication throughput, while satisfying sensing and covertness constraints. Our examination shows that in the non-adaptive mode, the optimal ρ decreases with the blocklength L, the number of RIS elements N, or Alice’s transmit power Pa, reflecting a stronger trade-off between covert throughput and sensing reliability. In contrast, in the adaptive mode, the optimal solution is ρ∗ = 1, indicating that Alice can fully rely on RIS adaptivity to conceal covert transmissions by switching its beamforming vectors. Numerical results further demonstrate a significant covert communication throughput gain of the adaptive mode over the non-adaptive mode, which increases with both N and Pa, highlighting the importance of RIS adaptivity in the ISACC systems.
Document Type
Journal Article
Date of Publication
1-1-2025
Publication Title
IEEE Journal on Selected Areas in Communications
Publisher
IEEE
School
School of Science
Funders
Taishan Young Scholar Project of Shandong (tsqn202306158) / Natural Science Foundation of Shandong (2024HWYQ-054) / National Key R&D Program of China (2023YFE0208800)
Copyright
subscription content
Comments
Zhang, J., Zhang, D., Liu, K., Sun, J., Li, M., & Yan, S. (2025). Integrated sensing and covert communications with RIS adaptive and non-adaptive modes. IEEE Journal on Selected Areas in Communications. Advance online publication. https://doi.org/10.1109/JSAC.2025.3639024