Intelligent Reflecting Surfaces Assisted Secure Transmission Without Eavesdropper's CSI

TL;DR

This paper proposes a joint beamforming and jamming strategy for IRS-assisted MISO systems to enhance security without requiring eavesdropper's CSI, using novel algorithms to optimize power and artificial noise.

Contribution

It introduces a practical approach for secure IRS-assisted transmission without eavesdropper's CSI, employing oblique manifold and MM algorithms for optimization.

Findings

Algorithms effectively optimize power and artificial noise.

Proposed methods improve security performance.

Simulation validates convergence and effectiveness.

Abstract

In this letter, improving the security of an intelligent reflecting surface (IRS) assisted multiple-input single-output (MISO) communication system is studied. Different from the ideal assumption in existing literatures that full eavesdropper's (Eve's) channel state information (CSI) is available, we consider a more practical scenario without Eve's CSI. To enhance the security of this system given a total transmit power at transmitter (Alice), we propose a joint beamforming and jamming approach, in which a minimum transmit power is firstly optimized at Alice so as to meet the quality of service (QoS) at legitimate user (Bob), and then artificial noise (AN) is emitted to jam the eavesdropper by using the residual power at Alice. Two efficient algorithms exploiting oblique manifold (OM) and minorizationmaximization (MM) algorithms, respectively, are developed for solving the resulting non-convex optimization problem. Simulation results have been provided to validate the performance and convergence of the proposed algorithms.