BBN 802.11 bbn_80211b_rx.py commandline?

I’m hoping one of the BBN people is reading this list… I checked
out the CVS code from acert.ir.bbn.com:/cvs/adroitgrdevel, and try
running bbn_80211b_rx.py like so:

$ /opt/gnuradio/bin/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

The first thing I notice is that it seems to be giving me 2.432G
instead of 2.437G? Also the dxc frequency is negative. And of
course, no packets get printed out.

Otherwise my gnuradio setup is fine, tested with lots of other
gnuradio code, etc. Did I make a mistake in my command line
arguments?

gr_fir_ccf: using SSE

The first thing I notice is that it seems to be giving me 2.432G
instead of 2.437G? Also the dxc frequency is negative. And of
course, no packets get printed out.

From just looking at what is being printed out, you may want to adjust
+5MHz from your baseband frequency. It looks like it tunes to your
baseband frequency +5MHz which causes an image to be correlated
against a 5MHz local oscillator (dxc?).

Then again, I’ve never worked with this software before so it is just
a guess from what I can see.

Brian

I am indeed reading the list :slight_smile:

desired freq = 2437000000.0
baseband frequency 2432000000.0

This looks ok - I think it’s trying to grab from above and below

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):

#!/bin/sh

$Id: etc:rc.d:gnuradio_80211,v 1.4 2006/09/12 15:40:00 gdt Exp $

PROVIDE: gnuradio_80211

BEFORE: measure

REQUIRE: DAEMON

KEYWORD: shutdown

$_rc_subr_loaded . /etc/rc.subr

name=“gnuradio_80211”
rcvar=$name
#command_interpreter=“python2.4”
command="/usr/adroit/lib/python2.4/site-packages/bbn_80211b_tap.py"
start_cmd=“gnuradio_80211_start”
stop_cmd=“gnuradio_80211_stop”

export PYTHONPATH=$PYTHONPATH:/usr/adroit/lib/python2.4/site-packages
export PATH=/usr/pkg/bin:/usr/adroit/bin:$PATH

gnuradio_80211_start()
{
$command > /tmp/gnuradio.log 2>&1 &
# Should have to bring tap0 up, but it’s up already.
# XXX wait for tap0 to come ready
sleep 10
}

gnuradio_80211_stop()
{
# SIGTERM doesn’t work
pkill -9 -f bbn_80211b_tap.py
}

load_rc_config $name
run_rc_command “$1”

We had this working on Linux as well, but it’s possible that the Linux
tap code is not quite right, or sensitive to your linux kernel
version. Last time I ran this (9/23), it printed out beacons from an
AP just fine (NetBSD, with our tap(4) changes for 802.11). I’ll be
trying again soon, I expect.

It is on my todo list to merge this code into the main repository.
But, that raises a lot of issues, such as teasing apart 802.11 receive
and tap processing, which really should be completely separate.

Thanks for responding so quickly.

I cvs updated this afternoon just before trying it. Have you moved to
a different (svn) repository? I’m using
[email protected]:/cvs/adroitgrdevel.

I cvs updated this afternoon just before trying it. Have you moved to
a different (svn) repository? I’m using
[email protected]:/cvs/adroitgrdevel.

That’s still where the best code is, and what we’re building from.
That said, it may not be quite right – our team has been doing things
other than GNU Radio for the last 8 weeks.

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