Secure Beamforming and Reflection Design for RIS-ISAC Systems Under Collusion of Passive and Active Eavesdroppers
For wireless communication systems vulnerable to colluding eavesdroppers, this work provides a security enhancement method, though it is an incremental extension of existing optimization techniques to a specific scenario.
The paper addresses physical-layer security in an RIS-aided ISAC system with cooperating passive and active eavesdroppers, proposing a joint beamforming and reflection design algorithm that maximizes secrecy rate while ensuring sensing performance. Numerical results show the algorithm's effectiveness and superiority over benchmarks.
In the paper, the physical-layer security for reconfigurable intelligent surface (RIS) aided integrated sensing and communication (ISAC) system is studied. There is an active eavesdropper (AE) as well as a passive eavesdropper (PE), and they cooperate each other. By joint base station beamforming and RIS reflection design, we aim to achieve the best secure data communications with guaranteed sensing performance. Mathematically, taking the constraints on sensing performance and transmission power in consideration, the system secrecy rate maximization problem is formulated with respect to transmit beamforming, RIS reflection, and receive beamforming. The formulated problem is non-convex and is decomposed to three subproblems by applying the alternating optimization (AO). For the decomposed subproblem, we utilize the quadratic penalty method and successive convex approximation (SCA) for the solution derivation. Thereafter, an iterative numerical algorithm, referred to as the joint beamforming and reflection design (JBRD) algorithm, is proposed. Finally, numerical results demonstrate the effectiveness and superiority of the proposed algorithm.