back to article Blight the power: Jamming attack cripples wireless signals using clever reflective technology

Wireless networking researchers have proposed a way to jam wireless signals without power. In a paper distributed through ArXiv, a group of boffins from universities in Australia, China, Singapore, and South Korea describe a technique that uses intelligent reflecting surface (IRS) technology, an emerging wireless signal …

  1. Chris G Silver badge

    Unless I am missing something, this is not passive as it depends on software interacting with surfaces that can react to relevant instructions from the software.

    That also means the idea can't just jam any old signal as the reflective surfaces will need to have locations 'between' the source and end point as well as the necessary properties to respond to the software.

    1. This post has been deleted by its author

    2. Version 1.0 Silver badge
      Happy

      I think is "passive" in the same way that a tick works, simply absorbing specific RF without radiating in a way that can be detected - sure a tick leaves a little hole but mostly you don't notice it at the instant that it bites, you just suffer afterwards. So you could have a situation where one manufacturers phone works but everyone else nearby has crappy reception.

      But maybe this is an opportunity to make an "RF eliminator" to sell to people who think that they are RF sensitive.

      1. Chris G Silver badge

        There is definitely a market there for 5G/Covid19/mind control free wallpaper and curtains, the RF sensitive would love a chance to get the tin foil off their heads.

        By the way, is that where half baked ideas come from?

        1. Mike 16 Silver badge

          Half-baked ideas

          That would be https://www.halfbakery.com/

    3. Pat Att

      It's passive in the sense that it's not generating any RF power of its own, and so is not detectable as a source of such power. A bit like how RFID tags in bank cards etc are passive - they modulate the impedance of the pickup coil, which is detectable by the transmit coil in the card reader, and so transmit energy without generating it. The term "semi-passive" is often used for such things.

      1. Dagg

        RFID tags are not passive. They actually emit RF and can be detected doing so.

  2. Kevin McMurtrie Silver badge

    But passive is more infuriating

    Anyone tried using an antenna next to a cluster of tall offices? Got it! Wait, it's fading.. just need a little adjustment.. no, yes, no, gah!

  3. JassMan

    Maybe something has been lost in translation.

    I think the use of passive and even the word power are taken as some sort of shorthand. I haven't read the original paper so I'm guessing that the IRS is an analog of a LED or paperInk at RF. It consumes minimal power the control reflection/transmission . Even if it remains in a given state once confgured it will still take power (possibly down in milliwatts) to change. Statefullness may also explain the use of 'passive'.

    It sounds like a useful material but they need to sort out their terminology.

  4. Pete 2

    An immobile solution

    > An IRS-enabled element like a wall ...

    I think the idea of hauling a wall around, just to jam someone's mobile phone, would be a bit of a giveaway.

    Although all this seems to be doing is reflecting the cellphone radio frequencies back, out of phase with the incoming one. The wavelength of an 1800MHz mobile signal is only 16cm. So you would only have to move the mobile phone a small amount to be away from the nulled out point. What would this wall do, if there were two cell towers that a phone could connect to?

    Even if the wall has the ability to track the position of a phone down to 1cm or so and can do that in real-time, there must be easier ways to futz with someone's signal.

    1. Anonymous Coward
      Anonymous Coward

      Re: An immobile solution

      Easier - sure dismantle the screening from a microwave oven and turn it on.

      Most things that use radio signals nearby are totally jammed.

      Don't stand too close though.... don't try this at home kids.

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