[Paper Review] IRS-based Wireless Jamming Attacks: When Jammers can Attack without Power

Bin Lyu, Dinh Thai Hoang+3 more|arXiv (Cornell University)|Jan 7, 2020

Advanced Wireless Communication Technologies9 references4 citations

TL;DR

This paper proposes a novel IRS-based jamming attack that uses intelligent reflecting surfaces to destructively interfere with legitimate wireless communications without consuming internal power. By jointly optimizing reflection coefficients and phase shifts, the IRS redirects the legitimate transmitter's signal to minimize received power at the legitimate receiver, achieving up to 99% reduction in signal power and outperforming conventional active jamming in certain scenarios.

ABSTRACT

This paper proposes to use Intelligent Reflecting Surface (IRS) as a green jammer to attack a legitimate communication without using any internal energy to generate jamming signals. In particular, the IRS is used to intelligently reflect the signals from the legitimate transmitter to the legitimate receiver (LR) to guarantee that the received signals from direct and reflecting links can be added destructively, which thus diminishes the Signal-to-Interference-plus-Noise Ratio (SINR) at the LR. To minimize the received signal power at the LR, we consider the joint optimization of magnitudes of reflection coefficients and discrete phase shifts at the IRS. Based on the block coordinate descent, semidefinite relaxation, and Gaussian randomization techniques, the solution can be obtained efficiently. Through simulation results, we show that by using the IRS-based jammer, we can reduce the signal power received at the LR by up to 99\%. Interestingly, the performance of the proposed IRS-based jammer is even better than that of the conventional active jamming attacks in some scenarios.

Motivation & Objective

• To investigate the feasibility of using Intelligent Reflecting Surfaces (IRS) as a passive, energy-free jammer in wireless networks.
• To address the lack of research on IRS as a malicious interference source, despite its growing use in enhancing network performance.
• To design a jamming strategy that leverages existing legitimate signals rather than generating new jamming signals.
• To optimize reflection coefficients and phase shifts to minimize the received signal power at the legitimate receiver.
• To evaluate performance against conventional active jamming attacks and demonstrate scenarios where passive IRS jamming outperforms active methods.

Proposed method

• The IRS is used to reflect signals from the legitimate transmitter (LT) to the legitimate receiver (LR), with controlled reflection coefficients and phase shifts.
• A joint optimization problem is formulated to minimize the total received signal power at the LR by adjusting both amplitude and phase of the reflected signals.
• The block coordinate descent (BCD) method is applied to alternately optimize the magnitudes of reflection coefficients and discrete phase shifts.
• For the continuous relaxation of phase shifts, semidefinite relaxation (SDR) and Gaussian randomization are used to obtain near-optimal solutions.
• The discrete phase shifts are obtained by quantizing the continuous solution, ensuring practical implementation.
• The optimization is solved iteratively, with the CVX tool used for efficient numerical computation of sub-problems.

Experimental results

Research questions

• RQ1 Can an IRS be used as a passive, energy-free jammer to degrade legitimate wireless communication without generating its own jamming signals?
• RQ2 How does the performance of IRS-based jamming compare to conventional active jamming attacks in terms of SINR degradation?
• RQ3 What is the impact of IRS size (number of reflecting elements) on the effectiveness of the jamming attack?
• RQ4 How do the distances between the LT, IRS, and LR affect the jamming performance?
• RQ5 Under what conditions can passive IRS jamming outperform active jamming despite the absence of internal transmit power?

Key findings

• The proposed IRS-based jammer reduces the received signal power at the legitimate receiver by up to 99% through destructive interference from direct and reflected links.
• In scenarios with low active jamming power (e.g., 15 dBm), the IRS-based jammer achieves better performance than active jamming due to precise phase and amplitude control.
• When the number of IRS reflecting elements reaches 200, the jamming performance surpasses that of active jamming with 35 dBm transmit power.
• The attack performance degrades when the distance between the LT and IRS exceeds 7 meters, due to reduced signal strength at the IRS.
• When the LR is within 8 meters of the IRS, the proposed scheme achieves SINR degradation comparable to active jamming with 35 dBm power.