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IRS-Enhanced Anti-Jamming Precoding Against DISCO Physical Layer Jamming Attacks

Huan Huang, Hongliang Zhang, Yi Cai, Yunjing Zhang, A. Lee Swindlehurst, Zhu Han

TL;DR

This work tackles physical-layer security threats from DISCO DIRS-based fully-passive jammers in MU-MISO systems by introducing a legitimate IRS to dampen DIRS-ACA interference and by designing an IRS-enhanced anti-jamming precoder that relies solely on statistical CSI of the DIRS-jammed channels. The authors derive an explicit SJNR expression for large DIRS sizes, reduce the original MINLP to a tractable form, and solve for active beamforming via an eigenvector-based rule and passive beamforming via Riemannian conjugate gradient on a complex circle manifold, followed by discretization to practical phase sets. Key contributions include (i) a joint active–passive beamforming framework that does not require cooperation with the illegitimate DIRS and (ii) a practical solution using a 2-bit IRS phase-shift quantization that achieves substantial jam-suppression gains with manageable complexity. Simulation results demonstrate significant performance gains of the proposed method over prior approaches, particularly at higher transmit powers, and show effective jamming mitigation with a modestly sized IRS and low phase resolution.

Abstract

Illegitimate intelligent reflective surfaces (IRSs) can pose significant physical layer security risks on multi-user multiple-input single-output (MU-MISO) systems. Recently, a DISCO approach has been proposed an illegitimate IRS with random and time-varying reflection coefficients, referred to as a "disco" IRS (DIRS). Such DIRS can attack MU-MISO systems without relying on either jamming power or channel state information (CSI), and classical anti-jamming techniques are ineffective for the DIRS-based fully-passive jammers (DIRS-based FPJs). In this paper, we propose an IRS-enhanced anti-jamming precoder against DIRS-based FPJs that requires only statistical rather than instantaneous CSI of the DIRS-jammed channels. Specifically, a legitimate IRS is introduced to reduce the strength of the DIRS-based jamming relative to the transmit signals at a legitimate user (LU). In addition, the active beamforming at the legitimate access point (AP) is designed to maximize the signal-to-jamming-plus-noise ratios (SJNRs). Numerical results are presented to evaluate the effectiveness of the proposed IRS-enhanced anti-jamming precoder against DIRS-based FPJs.

IRS-Enhanced Anti-Jamming Precoding Against DISCO Physical Layer Jamming Attacks

TL;DR

This work tackles physical-layer security threats from DISCO DIRS-based fully-passive jammers in MU-MISO systems by introducing a legitimate IRS to dampen DIRS-ACA interference and by designing an IRS-enhanced anti-jamming precoder that relies solely on statistical CSI of the DIRS-jammed channels. The authors derive an explicit SJNR expression for large DIRS sizes, reduce the original MINLP to a tractable form, and solve for active beamforming via an eigenvector-based rule and passive beamforming via Riemannian conjugate gradient on a complex circle manifold, followed by discretization to practical phase sets. Key contributions include (i) a joint active–passive beamforming framework that does not require cooperation with the illegitimate DIRS and (ii) a practical solution using a 2-bit IRS phase-shift quantization that achieves substantial jam-suppression gains with manageable complexity. Simulation results demonstrate significant performance gains of the proposed method over prior approaches, particularly at higher transmit powers, and show effective jamming mitigation with a modestly sized IRS and low phase resolution.

Abstract

Illegitimate intelligent reflective surfaces (IRSs) can pose significant physical layer security risks on multi-user multiple-input single-output (MU-MISO) systems. Recently, a DISCO approach has been proposed an illegitimate IRS with random and time-varying reflection coefficients, referred to as a "disco" IRS (DIRS). Such DIRS can attack MU-MISO systems without relying on either jamming power or channel state information (CSI), and classical anti-jamming techniques are ineffective for the DIRS-based fully-passive jammers (DIRS-based FPJs). In this paper, we propose an IRS-enhanced anti-jamming precoder against DIRS-based FPJs that requires only statistical rather than instantaneous CSI of the DIRS-jammed channels. Specifically, a legitimate IRS is introduced to reduce the strength of the DIRS-based jamming relative to the transmit signals at a legitimate user (LU). In addition, the active beamforming at the legitimate access point (AP) is designed to maximize the signal-to-jamming-plus-noise ratios (SJNRs). Numerical results are presented to evaluate the effectiveness of the proposed IRS-enhanced anti-jamming precoder against DIRS-based FPJs.
Paper Structure (10 sections, 1 theorem, 25 equations, 4 figures, 1 algorithm)

This paper contains 10 sections, 1 theorem, 25 equations, 4 figures, 1 algorithm.

Table of Contents

  1. Introduction
  2. System Description
  3. Temporal DIRS-based Fully-Passive Jamming
  4. Channel Model and Problem Formulation
  5. IRS-Enhanced Anti-Jamming Precoding Against DIRS-Based FPJ
  6. Active Beamforming Design
  7. Passive Beamforming Design
  8. Simulation Results and Discussion
  9. Conclusions
  10. Proof of Proposition \ref{['Proposition1']}

Key Result

Proposition 1

Under the condition that ${\boldsymbol{h}}_{{\rm{\!I}},k}$, ${\boldsymbol{h}}_{{\rm{\!D}},k}\!(t)$, and ${\boldsymbol{h}}_{{\rm{\!d}},k}$ are independent and ${\boldsymbol{h}}_{{\rm{\!I}},k}$ and ${\boldsymbol{h}}_{{\rm{\!d}},k}$ are unchanged during channel coherence time, $\eta_k$ defined in eqSLN where ${\beta _k} = {{{\mathscr{L}}\!_{{\rm G}}}{{\mathscr{L}}\!_{{\rm I},k}}{N\!_{\rm D}} }$, and

Figures (4)

  • Figure 1: The downlink of an MU-MISO system jammed by a temporal DIRS-based FPJ, where a legitimate IRS is introduced to resist the fully passive attacks launched by the temporal DIRS-based FPJ.
  • Figure 2: Ergodic rate per LU vs transmit power per LU.
  • Figure 3: Relationship between the ergodic rate per LU and the number of IRS reflective elements for different benchmarks, where the transmit power per LU is (a) 0 dBm and (b) -7 dBm, respectively.
  • Figure 4: Relationship between the ergodic rate per LU and the number of IRS quantified bits for different benchmarks, where the transmit power per LU is (a) 0 dBm and (b) -7 dBm, respectively.

Theorems & Definitions (1)

  • Proposition 1