Jammers can reduce signal power by up to 99%

Wireless network researchers have proposed a way to interfere with wireless signals without power. In an article distributed via ArXiv, a set of coffins from universities in Australia, China, Singapore, and South Korea described a technology using IRS (Intelligent Reflective Surface) technology, which is an emerging wireless signal optimization solution , Used to replace the signal to make the signal distortion improve you

IRS refers to software-defined radio and uses software to control how materials redirect radio frequency (RF) signals. Just like using acoustics to improve sound reflections in movie theaters and concert halls, IRS aims to improve the behavior of RF signals in different environments through software-controlled interfaces rather than fixed architectural elements. IRS-enabled elements (such as walls) will include a controller that communicates with a tunable chip that can be programmed to change the signal scattering characteristics of the surface to a target signal. The difference between it and the gain and forward signal relay is that it relies on passive beam steering technology without power components and active circuits for processing retransmissions.

Turning a good thing into a bad thing, the researchers explained that the described attack can disrupt the wireless communication system by changing the reflection of the signal without leaving an energy footprint, which makes detection and prevention difficult. “The reason is that in our proposal, the reflection coefficient and phase shift of all passive reflective elements can be carefully designed so that the total signal received by the legal receiver from the direct and reflective connection can be destructively added, which can be significant Lower the radio b sub and say: “receive power, thereby reducing the SINR on the LR”.

In the simulation results, they showed that their proposed IRS-based jammer can reduce signal power by up to 99%, and in some cases is better than traditional active signal portable jammer. Don’t panic. In the email sent to The Register, Sergi Abadal, research director of N3Cat at VISORSURF and a postdoctoral researcher at the Political University of Catalonia (UPC), said: “IRS research has recently produced many suggestions, most of which are Based on theoretical and simulation recommendations, some of these experimental prototypes are notable exceptions.”

Abadal said: “Many jobs recommend using IRS to support wireless communication (increasing coverage, signal strength, reducing interference, etc.). “Generally speaking, the way to increase signal strength is to design all reflections to reach the receiver in a way that can be’coherently combined’ (their phases are aligned and their performance is added together).”

He said: “So, theoretically, nothing can stop you from using similar techniques to reflect the signal to the receiver in a “destructive combination” (they are opposite in phase and interfere with each other).” To do this in this way Interfering signals, Abadal needs to know the location of the transmitter and expected receiver, which can be obtained by interacting with the access point or base station (it may be difficult if not allowed), or it can be obtained by deriving the location from the surrounding area . Signal detected. If it develops to more than one theoretical attack, the technology should be applicable to current wireless systems. Abadar said: “If the conditions are right, the IRS already exists and can determine the location of the sender and receiver to be interfered. This is possible in the current wireless system.”