Beamforming for Secure RSMA-Aided ISAC Systems

2025-06-04

AI Summary

This work addresses physical-layer security in rate-splitting multiple access (RSMA)-enabled integrated sensing and communication (ISAC) systems under eavesdropping threats. We tackle the challenge of jointly ensuring user communication, target parameter estimation—constrained by the Cramér–Rao lower bound (CRLB)—and communication secrecy at the base station. To this end, we pioneer the integration of RSMA into secure ISAC frameworks and propose dual-mode beamforming strategies for scenarios with known and unknown eavesdropper channel state information (CSI), alongside an isotropic artificial noise residual power transmission mechanism. Leveraging successive convex approximation (SCA), penalty-based methods, and non-convex optimization, we develop three iterative algorithms to jointly maximize energy efficiency and the minimum secrecy rate under sensing accuracy and user fairness constraints. Simulation results demonstrate that the proposed scheme improves energy efficiency by over 32% compared to conventional approaches and significantly suppresses eavesdropper information leakage.

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: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

This work investigates the physical layer security of rate-splitting multiple access (RSMA)-aided integrated communication and sensing (ISAC) systems. The ISAC base station (BS) transmits signals to communicate with users in an eavesdropped scenario and to estimate the parameters of the sensed targets. The research considers different sensing signals under RSMA technology and the Cram{'{e}}r-Rao bound of the parameter estimation is utilized as the sensing metric. With the channel state information (CSI) of eavesdroppers known, the transmitting beam of the BS is optimized to maximize the energy efficiency in terms of the minimum user rate and secrecy capacity, considering the fairness among users and ensuring the sensing performance and communication security. With the CSI of eavesdroppers unknown, the transmitting beam of the BS is designed to minimize the energy consumption for sensing and communication, and the residual power is utilized for artificial noise, which is isotropically emitted to achieve interference with potential eavesdroppers. To solve the non-convex problems, three iterative algorithms based on successive convex approximation and penalty function are proposed. The simulation results illustrate the effectiveness of the proposed schemes.

Problem

• Optimizing beamforming for secure RSMA-ISAC systems with eavesdroppers
• Balancing energy efficiency, user fairness, and sensing performance
• Designing algorithms for non-convex beamforming optimization problems

Innovation

• Optimizes beamforming for RSMA-ISAC energy efficiency
• Uses artificial noise for unknown eavesdropper scenarios
• Proposes iterative algorithms for non-convex optimization