BBN 802.11 bbn_80211b_rx.py

I’m having the same problem as here
http://www.ruby-forum.com/topic/87459

I got the code: cvs -d [email protected]:/cvs/adroitgrdevel co
adroitgrdevel
Then build it using bootstrap/configure/make/make install to the same
prefix
as gnuradio(/usr/local)

I ran the python script in
/adroitgrdevel/gr-bbn/src/examples/bbn_80211b_rx.py just like this:

./bbn_80211b_rx.py -f 2.437G -v -b
Bits Per Encoded Sample = 8
adc frequency = 64000000
decimation frequency = 16
input_rate = 4000000
gain = 45.0
desired freq = 2437000000.0
baseband frequency 2432000000.0
dxc frequency -5000000.0
Samples per data bit = 8

gr_fir_ccf: using SSE

2.432G is used instead of 2.437G. Also the dxc frequency is negative.
And
no packets get printed out.

BTW, what does that guy mean “Not sure when you updated, but we have
changed
the checked in code to default to 2437, and run it like this (as a
NetBSD
rc.d start script)”, following the above link?

Thanks, waiting for help

View this message in context:
http://www.nabble.com/BBN-802.11-bbn_80211b_rx.py-tp18642793p18642793.html
Sent from the GnuRadio mailing list archive at Nabble.com.

BTW, what does that guy mean “Not sure when you updated, but we have
changed
the checked in code to default to 2437, and run it like this (as a
NetBSD
rc.d start script)”, following the above link?

It means there is somewhere checked in a script that fits into the
NetBSD rc.d framework so that GNU Radio is started at boot time.

Our code expected to stuff received packets into a tap(4) device.

I would suggest digging into the code a bit and adding some debug print
statements. (If you aren’t comfortable doing that, this code isn’t for
you!)

BTW, what does that guy mean “Not sure when you updated, but we have
changed
the checked in code to default to 2437, and run it like this (as a
NetBSD
rc.d start script)”, following the above link?

details if you care, but surely they have little to do with your issues.

http://www.netbsd.org/docs/guide/en/chap-rc.html

about your output:

./bbn_80211b_rx.py -f 2.437G -v -b
Bits Per Encoded Sample = 8
adc frequency = 64000000
decimation frequency = 16
input_rate = 4000000
gain = 45.0
desired freq = 2437000000.0
baseband frequency 2432000000.0
dxc frequency -5000000.0
Samples per data bit = 8

gr_fir_ccf: using SSE

2.432G is used instead of 2.437G. Also the dxc frequency is negative.
And
no packets get printed out.

I am unclear on dxc.

Are you sure there are strong signals at the 1 Mb/s rate on 2437 MHz?

/adroitgrdevel/gr-bbn/src/examples/bbn_80211b_rx.py just like this:

What operating system are you running on? That script may be expecting
the NetBSD tap device, and your system’s might be different.

I’m not sure of the frequency so I tried

./bbn_80211b_rx.py -f 2.462G -d 8 -b -v
Bits Per Encoded Sample = 8
adc frequency = 64000000
decimation frequency = 8
input_rate = 8000000
gain = 45.0
desired freq = 2462000000.0
baseband frequency 2460000000.0
dxc frequency -2000000.0
Samples per data bit = 8

gr_fir_ccf: using SSE
PKT: len=77, rssi=-22, src=00:13:46:16:28:AA, time=557560, rate=1 Mbps
PKT: len=77, rssi=-29, src=00:13:46:16:28:AA, time=1786312, rate=1 Mbps
PKT: len=77, rssi=-26, src=00:13:46:16:28:AA, time=1991192, rate=1 Mbps
PKT: len=77, rssi=-27, src=00:13:46:16:28:AA, time=2195928, rate=1 Mbps
PKT: len=77, rssi=-19, src=00:13:46:16:28:AA, time=2912744, rate=1 Mbps
PKT: len=77, rssi=-28, src=00:13:46:16:28:AA, time=3527168, rate=1 Mbps
PKT: len=77, rssi=-25, src=00:13:46:16:28:AA, time=3936776, rate=1 Mbps
PKT: len=77, rssi=-26, src=00:13:46:16:28:AA, time=4141640, rate=1 Mbps
PKT: len=77, rssi=-24, src=00:13:46:16:28:AA, time=4858456, rate=1 Mbps
PKT: len=77, rssi=-26, src=00:13:46:16:28:AA, time=5063192, rate=1 Mbps
PKT: len=77, rssi=-21, src=00:13:46:16:28:AA, time=5268192, rate=1 Mbps

This time packets are received. It seems to me that (desired freq) +
(dxc
frequency) = (baseband frequency)

BTW, I’m in Ubuntu 8.04

Greg T. wrote:

dxc frequency -5000000.0

http://lists.gnu.org/mailman/listinfo/discuss-gnuradio


View this message in context:
http://www.nabble.com/BBN-802.11-bbn_80211b_rx.py-tp18642793p18654729.html
Sent from the GnuRadio mailing list archive at Nabble.com.

On Fri, Jul 25, 2008 at 07:46:58AM -0400, Greg T. wrote:

./bbn_80211b_rx.py -f 2.437G -v -b

2.432G is used instead of 2.437G. Also the dxc frequency is negative. And
no packets get printed out.

I am unclear on dxc.

That part is fine. dxc = digital down converter (DDC) or DUC depending
on the context.
In this case he wanted 2.437G. The front end was tuned to 2.432G, thus
the DDC needed to be set to -5M to get the desired frequency translated
to 0 Hz in the complex baseband.

Eric

What does “combination of the LO in the front end and the digital
downconverter” mean please?

Eric B. wrote:

None of the above. I’m just decoding the details of how the usrp was

BTW, what does that guy mean "Not sure when you updated, but we have
about your output:
Samples per data bit = 8
In this case he wanted 2.437G. The front end was tuned to 2.432G, thus
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio


View this message in context:
http://www.nabble.com/BBN-802.11-bbn_80211b_rx.py-tp18642793p18693934.html
Sent from the GnuRadio mailing list archive at Nabble.com.

On Fri, Jul 25, 2008 at 10:11:34AM -0700, Y. Zhuang wrote:

http://en.wikipedia.org/wiki/List_of_WLAN_channels

Is it because the channel for 802.11 in 2.432G there, so the front end
was tuned to 2.432G? But there is 2.437G as well.
Or the font end is just picking the strongest channel it finds? Thanks

Y

None of the above. I’m just decoding the details of how the usrp was
tuned using a combination of the LO in the front end and the digital
downconverter. The command line shows -f 2.437G. See the excellent
USRP FAQ for additional info. http://gnuradio.org/trac/wiki/UsrpFAQ

Eric

On Mon, Jul 28, 2008 at 12:28 PM, yyzhuang [email protected] wrote:

What does “combination of the LO in the front end and the digital
downconverter” mean please?

For general radio architecture, please see:

http://en.wikipedia.org/wiki/Superheterodyne

Generally, the LO/synthesizer has some discrete step size (12.5kHz,
250kHz, etc). To get down to baseband, the resultant signal is then
shifted in frequency down using the digital downconverter:

http://en.wikipedia.org/wiki/Digital_Down_Converter

Brian

Thanks.

When I use "./bbn_80211b_rx.py -f 2.44G -v -b ", no packets get printed
out.
But the output of "./bbn_80211b_rx.py -f 2.462G -d 8 -b -v " is normal,
we
got a bunch of packets:

Bits Per Encoded Sample = 8
adc frequency = 64000000
decimation frequency = 8
input_rate = 8000000
gain = 45.0
desired freq = 2462000000.0
baseband frequency 2460000000.0
dxc frequency -2000000.0
Samples per data bit = 8

gr_fir_ccf: using SSE
PKT: len=77, rssi=-22, src=00:13:46:16:28:AA, time=557560, rate=1 Mbps
PKT: len=77, rssi=-29, src=00:13:46:16:28:AA, time=1786312, rate=1 Mbps
PKT: len=77, rssi=-26, src=00:13:46:16:28:AA, time=1991192, rate=1 Mbps

I checked the code:

parser.add_option("-d", “–decim”, type=“int”, default=16,
help=“set fgpa decimation rate to DECIM
[default=%default]”)
parser.add_option("-b", “–barker”, action=“store_true”,
default=False,
help=“Use Barker Spreading
[default=%default]”)

-d 8 is setting the fpga decimation rate to 8, and -b means Use Barker
Spreading. How should we know what decimation rate and spreading to use?
Thanks.

BTW, if one ursp for tx and one for rx, we dont have to specify these
options:
on the sending side: ./bbn_80211b_rx.py -f 2.44G -v -b
Using TX d’board A: Flex 2400 Tx MIMO B

gr_fir_ccf: using SSE
spb: 8
interp: 32
(spb = samples/baud, default 8; interp = fpga interpolation rate,
default 32
)

on the receiving side: ./bbn_80211b_tx.py -f 2.44G
Bits Per Encoded Sample = 8
adc frequency = 64000000
decimation frequency = 16
input_rate = 4000000
gain = 45.0
desired freq = 2440000000.0
baseband frequency 2436000000.0
dxc frequency -4000000.0
Samples per data bit = 8

gr_fir_ccf: using SSE
PKT: len=1477, rssi=-10, src=20:61:6e:64:20:73, time=16024824, rate=1
Mbps
PKT: len=1477, rssi=-12, src=20:61:6e:64:20:73, time=16036920, rate=1
Mbps
PKT: len=1477, rssi=-11, src=20:61:6e:64:20:73, time=16049016, rate=1
Mbps
PKT: len=1477, rssi=-13, src=20:61:6e:64:20:73, time=16061112, rate=1
Mbps

Thanks!

Brian P. wrote:

Generally, the LO/synthesizer has some discrete step size (12.5kHz,
[email protected]
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio


View this message in context:
http://www.nabble.com/BBN-802.11-bbn_80211b_rx.py-tp18642793p18700741.html
Sent from the GnuRadio mailing list archive at Nabble.com.

This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs