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I have seen several projects now which derive novel spatial information from radio data collected from a typical wireless router:

http://wisee.cs.washington.edu/

http://www.extremetech.com/extreme/133936-using-wifi-to-see-through-walls

The idea of using a wireless router as a sort of passive radar is fantastic.

I am very interested in experimenting with data collected from a wireless router myself, but there is little information on how to go about actually interfacing with a wireless router and getting a raw stream of information collected by the device. Similar questions have been asked on here before, but I am yet to see a satisfactory answer.

I don't have the rep points necessary to link to the other questions but see:

'Capture Raw Signal from WiFi card as You Would a Sound Card'

'raw wifi “signal data” access'

I am looking for a solution that would let me use a low-cost device such as the oh so common WRT54G wireless router. If your answer involves custom radio hardware, you needn't bother posting.

metaColin
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  • In general you need to set your wifi card to the monitor mode than you can simple dump the data e.g. with wireshark or aircrack. – rekire Jun 23 '13 at 19:01
  • From the reading I've done so far, a wireless card would not be sufficient on it's own. The research I've seen uses devices with at least 2 antennas. Additional wireless devices might be incorporated to augment a system, but a single point of measurement would likely be insufficient. – metaColin Jun 23 '13 at 19:06

2 Answers2

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If you read the wisee research paper you will find the platform they use for the system, it is USRP N210 from Ettus plus GNU radio software. So it is not your usual WiFi AP they are using but the SDR solution this question also hints about.

WiFi devices are build to handle physical layer in silicon and the monitor mode is the best thing you can get without going the SDR path. You can get quite a lot of information from it - the radiotap header contains for example received signal strength and receiving antenna information. But if you really want to explore physical layer of WiFi then commodity hardware is not going to cut it.

Community
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Raber
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  • I went and looked at the paper, and you are correct about the hardware they used. Alas I don't have 1700$ to spend on a special radio. In their video & faq they do imply that their capture methods could be used with standard wifi devices. From the FAQ: "So WiSee is a stand-alone device? Not necessarily. It could be potentially implemented in today's wireless devices in the near future." – metaColin Jun 26 '13 at 23:41
  • I am disappointed no one else had comments to offer, so I accepted this answer. Although I do suspect someone, somewhere knows how to achieve some rudimentary radar functionality via a typical wi-fi router... – metaColin Jul 02 '13 at 04:47
  • Hi Colin, Have you since been able to find a solution? I have a very similar need where I'd like to use a combination of a few simple wifi routers to approximate the location or trajectory of any smartphone by capturing its wi-fi pings. – Arun Jose May 05 '14 at 07:39
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As far as I know, the only option using a commodity hardware is to use Intel 5300 Wifi card. You can get the complex CSI (amplitude and phase info therein) from the three antenna on it from a sample of subcarriers (OFDM). You can take a look at this site:

http://dhalperi.github.io/linux-80211n-csitool/

Shagru
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