Beamforming for Secure RSMA-Aided ISAC Systems

TL;DR

This paper explores physical layer security in RSMA-aided ISAC systems, optimizing beamforming strategies to enhance secrecy and sensing performance under different CSI scenarios, using iterative algorithms.

Contribution

It introduces novel beamforming optimization methods for secure RSMA-based ISAC systems considering both known and unknown eavesdropper CSI.

Findings

Optimized beamforming improves secrecy capacity.

Artificial noise effectively hinders eavesdroppers.

Proposed algorithms converge efficiently in simulations.

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.