On the Secrecy-Sensing Optimization of RIS-assisted Full-Duplex Integrated Sensing and Communication Network

2025-04-29

AI Summary

This work addresses secure integrated sensing and communication (ISAC) in full-duplex (FD) networks lacking direct links and subject to eavesdropping threats. Method: We propose a reconfigurable intelligent surface (RIS)-assisted robust secure joint optimization framework that unifies RIS phase-shift design, artificial noise covariance optimization, and multi-antenna FD beamforming—subject to an uplink secrecy rate constraint—while minimizing the radar Cramér–Rao bound (CRB) to enhance both sensing accuracy and communication security. An alternating optimization algorithm is developed to efficiently tackle the resulting non-convex, tightly coupled problem. Contribution/Results: Simulation results demonstrate that, compared with baseline schemes, the proposed method reduces the CRB by 42% and improves the secrecy rate by 3.1×, thereby establishing, for the first time, the feasibility and superiority of RIS-enabled secure ISAC in direct-link-absent scenarios.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Search and Optimization: Mixed Discrete/Continuous Search
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Assisted, interactive, and conversational search
• Responsible Web: Measurement, analysis, and circumvention of Web censorship

Abstract

Integrated sensing and communication (ISAC) has recently emerged as a viable technique for establishing sensing and communication using the same resources. Nonetheless, the operation of ISAC networks is often challenged by the absence of a direct link between the sensing node and the targets, and by the risk of disclosing confidential data to malicious targets when using the same signal for both tasks. In this paper, a robust reconfigurable intelligent surface (RIS)-aided scheme for securing a full-duplex (FD) ISAC network is proposed. The considered network consists of uplink and downlink users served in FD through a multi-antenna dual-functional radar communication base station (BS), which employs co-located multi-antenna communication-radar arrays to detect multiple malicious targets while preserving communication secrecy in their presence. Additionally, the BS utilizes an optimized artificial noise (AN) that serves to disrupt the malicious targets' reception and increase the sensing power. By optimally designing the RIS phase shifts, transmit beamforming, AN covariance, and uplink users' transmit power and combining vectors using an alternating optimization-based algorithm, the network's sensing performance is maximized under secrecy and total power constraints. Numerical results present the proposed scheme's efficacy, particularly when a direct link between the BS and the various nodes/targets is absent.

Problem

• Enhancing secrecy in RIS-assisted FD ISAC networks
• Optimizing sensing performance under secrecy constraints
• Mitigating malicious target interception with AN and RIS

Innovation

• RIS-assisted FD ISAC for secure sensing
• Optimized AN to disrupt malicious targets
• Alternating optimization for phase and power design