Wi-Fi signal to LabVIEW

[Sparkette]

Is there any way I can acquire the RF signal from my Wi-Fi card and put it in LabVIEW? It should be possible, as all the hardware is right there.

[Justin Reina]

Hello flarn,

(1) What wifi card do you have?

(2) What is your ultimate objective? (i.e. WLAN hacking, etc..)

-Justin

[Norm Kirchner]

One thing that you might not realize is that the signal goes right into a WLAN processing chip and the code on the chip was never made able to export signals. Instead it does it's function by taking the RF on the Analog Front End (AFE) and getting it into the bits that really need to be processed as efficiently and quickly as possible.

So although there is a downconverter (RF -> IF :: GHz -> MHz) and a A/D converter (Analog -> I-Qbits) you do not have access to those raw bits of data before they get put into the WLAN processing stack

A great place to learn more about RF is at

http://decibel.ni.com/content/groups/rf-developers-network

[jdunham]

QUOTE (flarn2006 @ Mar 29 2009, 05:40 PM)

Is there any way I can acquire the RF signal from my Wi-Fi card and put it in LabVIEW? It should be possible, as all the hardware is right there.

Ah, but the difficulty lies in the software. All hardware in a computer is controlled by hardware drivers, and just like any program, LabVIEW needs to invoke the drivers to get the juice from whatever hardware is connected. Usually the hardware manufacturer creates the driver. The driver will expose an API for other programs to access its features. If the author doesn't think anyone needs the feature, he or she (it's probably a team) won't waste money adding the API function to access it. If the authors think that exposing the feature would leak the company's engineering secrets, then they definitely won't add it to the API.

So without knowing too much about what hardware you have or what you're trying to do, it seems really unlikely. The RF signal itself is unlikely to be digitized into a stream of bits like the other analog signals LabVIEW users typically digitize. Usually the hardware demodulates the RF signal into something which can be represented by a digital stream at a lower rate. In other words, the radio-frequency voltage waveform goes through lots of non-digital (not computer accessible) hardware processing before it is reduced to the WiFi bitstream.

You can read more about http://en.wikipedia.org/wiki/Software-defined_radio' rel='nofollow' target="_blank">software-defined radio if you are interested in the possibilities, but it's pretty unlikely that one of these is hiding inside your WiFi card.

[Justin Reina]

Hello Norm,

Correct me if I am wrong, but if the manufacturer provided access to the WLAN chipset, and if some lucky soul obtained this information,

then could it be possible to achieve this objective?

What I was trying to get at is the basic layout of a commercial wifi card (my guess as to flarn2006's weapon of choice):

Step One:

-A wifi card has a crap-ton of way cool hardware on it. But the deal is, your wifi-card manufacturer didn't design all of it.

-One of these components is the WLAN (i.e. wifi) chipset. This is the HW that 'listens' and 'talks' into the RF domain (i.e. 'air').

Pretty proprietrary stuff here, these guys are greedy and don't share info on their chip unless you pay, like your wifi card guys did.

Step Two:

-Your wifi-card guys used their own hardware to control the WLAN chipset using that proprietary IO info that they bought.

But chances are they didn't provide this 'access' at the outermost layer (the layer you have access to).

-In fact almost assuredly they didn't because the stuff is proprietrary, and again they are greedy (Broadcom?? )

Step Three:

-There may be some gem out there, but maybe steer towards some other ideas

-A Packet sniffer: http://www.cacetech.com/products/airpcap_family.htm

*Coolest stuff ever. Take a look into 'Wireshark' http://en.wikipedia.org/wiki/Wireshark

-Software Defined Radios (SDR): http://en.wikipedia.org/wiki/Software-defined_radio

*Cool FPGA implementation: http://instruct1.cit.cornell.edu/courses/e...ftwareRadio.pdf

Last Note:

-Would you guess most guys building wireless devices hate paying for the proprietary, shrouded WLAN chipsets?

SDR is becoming quite a prospect and is definetly worth checking out.

Best of Luck,

Justin

*flarn2006: From the look of your posts you seem pretty young and pretty curious. What point of school are you at? Keep up

the curiosity.

*all: Please correct any mistakes I may have made in this post. I didn't confirm all facts, but am pretty confident

in their validity.

[Jason H]

QUOTE (flarn2006 @ Mar 29 2009, 05:40 PM)

Is there any way I can acquire the RF signal from my Wi-Fi card and put it in LabVIEW? It should be possible, as all the hardware is right there.

It really depends on what you are trying to do.

• If you want to access your wireless card in LabVIEW from your PC, Then you need to go through the driver in windows. The driver itself is proprietary, so you cannot, for example, transmit your own raw CCK or OFDM signals. You can only send 802.11 packets, at best.
  

• If you are interested in taking your wifi card and making a separate embedded system out of it, then you run into the issues just mentioned. You would essentially have to build your own driver. Even then you may not be able to send your own raw modulated signals because the MAC may be embedded onto the chip. So you could still be stuck with the 802.11 protocol. Even if the MAC wasn't on the chip, I doubt it would be feasible to make a driver for it.
  

• I think, however, you are talking about just sending 2.4 GHz RF, for example, a 2.4 GHz continuous sine wave. And you most likely want to do this from your PC. There are a couple of problems with this. First of all, you have very limited control over your RF from windows. This is because all radios must comply to regulatory FCC and ETSI restrictions which strictly limit the power output, modulation type and quality, and a number of other things. So basically, it is impossible for you to send anything other than perfect wi-fi packets. Second, assuming you could hack every aspect of the chip, the chip can only physically output OFDM and CCK modulations. Software defined radios, as has already been mentioned, are designed for this type of arbitrary RF control. I think that is probably what you are interested in.
  

[Phillip Brooks]

A bit of research turned up a product called AirMedic that takes advantage of the newer Intel 5100 and 5300 series wireless adapters. No additional external receiver or other hardware. Unfortunately, there is no mention of an API, and the software appears to cost ~ $1000 US. :thumbdown:

I suppose with enough effort and proper documentation for the Intel hardware/drivers it might be possible to recreate it, but considering the cost of AirMedic, I'm guessing this wouldn't be a weekend project...

I remember seeing something called the Wi-Spy 2.4 GHz receiver on ThinkGeek some time ago. The original version is available for $199 US. I poked around on the manufacturer's web site ( www.metageek.net ) and couldn't find any info about an API for the Wi-Spy products; but there is something that you could look at called inSSIDer. It appears to use .NET API functions ( XP sp2 and Vista) to report WiFi statistics.

The inSSIDer code is open source. :thumbup:

[metageektrent]

QUOTE (Phillip Brooks @ Mar 30 2009, 11:34 AM)

I remember seeing something called the Wi-Spy 2.4 GHz receiver on ThinkGeek some time ago. The original version is available for $199 US. I poked around on the manufacturer's web site ( www.metageek.net ) and couldn't find any info about an API for the Wi-Spy products; but there is something that you could look at called inSSIDer. It appears to use .NET API functions ( XP sp2 and Vista) to report WiFi statistics.

The inSSIDer code is open source. :thumbup:

Hi, I hope you don't mind me jumping in. We do release an API for the Wi-Spy 2.4x, it currently isn't published, but we'll send the documentation to anyone who emails us. If you are a developer and own a Wi-Spy, send us an email! There is an open source version called SpecTools, and that was created by the author of Kismet.

We have a perl script that will convert the live data into a CSV, which a lot of people find useful too.

The Wi-Spy will show all radio activity in the 2.4GHz band like Wi-Fi, microwaves, cordless phones, bluetooth, and many others.

Thanks for the link, Phillip.