
Researchers create super-efficient Wi-Fi - pavornyoh
http://arstechnica.com/information-technology/2016/02/researchers-create-super-low-power-wi-fi/
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avian
While this is interesting work, I would say it's going into the wrong
direction. It is simplifying the devices at the cost of less efficient use of
the already crowded radio spectrum (the plugged-in device must transmit the
carrier wave and the reflections from passive devices consume twice the
spectrum due to mirror frequencies) Everyone else is going the other way:
complicating devices to achieve higher spectrum efficiency. This approach
might be sustainable for spy agencies, but I don't see how it could scale to
mass deployment (especially with device densities predicted by IoT pundits
these days).

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ptha
Mentioned in the article is the passive bug the Soviets used for covert
listening in the US embassy in Moscow. Impressive technology for 1945:
[https://en.wikipedia.org/wiki/The_Thing_%28listening_device%...](https://en.wikipedia.org/wiki/The_Thing_%28listening_device%29)

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themadcreator
The NSA ANT catalog of spy devices (leaked by Snowden) also includes cheap
analog retro-reflectors:
[https://en.wikipedia.org/wiki/NSA_ANT_catalog](https://en.wikipedia.org/wiki/NSA_ANT_catalog)

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sengstrom
Wondering why the two passive devices have the same mac address...

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taterbase
Nice catch, I haven't read the paper yet but I wonder if it belongs to the
device generating the frequency.

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dogma1138
Shouldn't since the passive devices build the packets the MAC is probably the
same because it's they just copied the same exact fpga code on both devices.

What wasn't clear and should be mentioned is that the active device doesn't
have to transmit wifi at all it's just a source of random rf radiation at
compatible frequencies since you craft packets by selective reflecting the
signal.

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lucaspiller
The same researchers released a video demonstrating the basics of this (though
not with WiFi) a few years ago:

[https://www.youtube.com/watch?v=gX9cbxLSOkE](https://www.youtube.com/watch?v=gX9cbxLSOkE)

[https://homes.cs.washington.edu/~gshyam/Papers/amb.pdf](https://homes.cs.washington.edu/~gshyam/Papers/amb.pdf)

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stuaxo
Wonder why they chose the UK "health lottery" \- quite a small lottery, vs the
UK National Lottery ?

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themadcreator
This is pretty incredible, and congrats to the research team!

But, could you please not use phrasing like "Reduces Power 10,000x". I don't
think I'm the only that has an aversion to this:
[http://timesless.com/](http://timesless.com/)

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thaumasiotes
[http://www.xkcd.com/169/](http://www.xkcd.com/169/)

Get over yourself.

In particular, your page of drivel goes wrong here:

> "smaller than", "less than" etc. indicate subtraction, as in: _2 less than
> 10 is 8._

Believe it or not, "smaller than" and "less than" are also used to refer to
being smaller or lesser (go figure) in size or amount, as in "2 is less than
10".

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Angostura
That's pretty rude. The poster was only asking for something that would
improve clarity.

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thaumasiotes
> The poster was only asking for something that would improve clarity.

This is not true. There is no issue of clarity if I say "the effect of losing
a leg on quality-adjusted life years is four times smaller than the effect of
smoking", or at least, no ambiguity about how the two numbers I'm thinking of
relate to each other (numbers wholly invented). The poster was asking us to
conform to his personal peeves.

