IRS Facilitating Security Zone Formation of Zero Trust in the MU-MISO-ME Wireless Network

Zero trust is envisioned as a promising network paradigm for verifying the legitimacy of users before accessing the network at all times. However, most existing related works focused on the network layer instead of the physical layer. In this letter, we propose a secure physical layer transmission scheme powered by the intelligent reflecting surface (IRS) to reinforce the security zone (SZ) boundary of a zero trust network. Specifically, we consider a practical multi-user multiple-input single-output multi-eavesdropper (MU-MISO-ME) wireless network. A max-min fairness (MMF) problem of secrecy rate (SR) is formulated to jointly design the confidential message (CM) beamforming, artificial noise (AN) vector, and the reflection coefficient (RC) of IRS. We propose a generalized power iteration along with minorization maximization (GPI-MM) algorithm with low complexity to solve the non-convex problem. Simulation results demonstrate the superiority of the proposed scheme in enhancing security boundary, verifying the effectiveness in promoting SZ formation for the zero trust network.