Jammers can reduce signal power by up to 99%

Wireless network researchers have proposed a way to destroy wireless signals without power. In an article published through ArXiv, a set of coffins from universities in Australia, China, Singapore, and South Korea described a technique that uses IRS (Intelligent Reflective Surface) technology (an emerging wireless signal optimization scheme) To replace the signal to interfere with the signal. 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, the goal of IRS is to improve the behavior of RF signals in different environments through software-controlled surfaces rather than fixed architectural elements.

Elements with IRS capabilities (such as walls) will contain a controller that communicates with a tunable chip that can be programmed to change the signal dispersion characteristics of the surface to the target signal. The difference between it and the gain and forward signal relay is that it relies on passive technology to control beam steering without the need for power components and active circuits to handle 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 way the signal is reflected, and doing so does not leave an energy footprint, which makes detection and prevention difficult.

“The reason is that in our proposed scheme, 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 links can be destructively added. Significant reduction in radio boffins said that the received power and therefore reduced the SINR at 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, its performance is better than traditional active signal cell phone jammer. Don’t panic. In an email to The Register, Sergi Abadal, research director of N3Cat at VISORSURF and a postdoctoral researcher at the Politecnico de Catalunya (UPC), said: “The recent explosive growth of IRS research includes many suggestions. , Most of which are based on theoretical and simulation suggestions, with some experimental prototypes as obvious exceptions.”

After reviewing the paper briefly, he emphasized that it is theoretical and the results must be treated with caution until experimental verification is obtained. But he allowed the described technology to look reasonable. Abadar said: “Many work has suggested the use of IRS to assist wireless communications (increase coverage, signal strength, reduce interference, etc.). “Usually, the way to increase signal strength is to make all the reflections so that they reach the receiver in a way that can be’coherently combined’ (their phases are aligned and their power is added together).”

He explained: “So, theoretically, nothing can prevent you from using similar techniques to reflect signals to the receiver in a “destructive combination” (they are opposite in phase and interfere with each other).” For this To block the signal in such a way, Abadal will need to know the location of the transmitter and the intended receiver, which can be obtained by interacting with the access point or base station (which may be difficult if the operation is improper), or these locations can be inferred from the area Detected signal.

If this technology develops more than just a theoretical attack, then it should be applicable to current wireless systems. Abadar said: “If the conditions are right-the IRS exists and the location of the sender and receiver it is trying to interfere with can be inferred-then it is possible in the current wireless system.”

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