Re: [Discuss-gnuradio] [Douglas Geiger BBN 802.11b] Porting code on USRP2 problems

[Valerio, Danilo]

Hi Colby!

We have also tried without success.
We have used the TX path from Tiago and a modified version of the RX path (firmware and FPGA at their latest update).
I also felt confident that the the TX path works, and consequently that the RX path had some problem.

So we have tried to transmit with the USRP2 and receive with a real IEEE802.11 chipset (Ralink chipset RT2500).
This chipset has no firmware and we modified the linux driver so as to:
- avoid mac CRC (Everything received on the MAC layer is passed to the higher layers);
- set fixed modulation schemes (i.e. DBPSK 1Mbps);
- set PLCP long preamble.
- set complete monitor/passive mode.

The chipset detects some transmitted frames. This could be an indication that the PLCP preamble/header is correct (?).
However the PLCP payload is just rubbish.
We have also tried to submit stupid payloads (like ffffffff) and I have the impression that what we receive is just random. :-(

If we obtain some successful result in the next few days, I'll let you know!

Best Regards,
Danilo

On Friday 17 April 2009 09:17:38 Colby Boyer wrote:
> Hi All,
>
> I've been trying to run some hardware tests between two USRP2s, but I have
> had no success in receiving packets. I am using the modified TX from Tiago.
> I feel sorta confident that the TX code works, because when I run the
> usrp2_fft.py, I see a wave form being transmitted over the channel.
>
> Has anyone have any success on receiving packets between two USRP2s? When
> RX/TX there is a usrp2::ctor reset db failed error. Could this cause
> problems for the RX/TX? I am using the firmware that was shipped with the
> USRP2.
>
> Thanks,
> Colby Boyer
>
> On Wed, Apr 15, 2009 at 10:40 AM, Ben Yahmed <
> address@hidden> wrote:
>
> > Hi all,
> >
> > Since I have tested the tx code (bbn_80211b_tx_port2.py), I wanted to run
> > the bbn_80211b_rx.py inorder to capture the packets sent but I encountred
> > this error:
> >
> >
> > # ./bbn_80211b_rx.py Traceback (most recent call last):
> > File "./bbn_80211b_rx.py", line 179, in <module>
> > main ()
> > File "./bbn_80211b_rx.py", line 174, in main
> > app = app_flow_graph()
> >
> > File "./bbn_80211b_rx.py", line 159, in __init__
> > self.u = usrp_rx(0, options.decim, options.rx_subdev_spec,
> > options.width_16, options.verbose, options.gain, options.freq)
> > File "./bbn_80211b_rx.py", line 97, in __init__
> >
> > self.u.set_decim(decim_rate=(decim * 1.5))
> > File "/usr/local/lib/python2.5/site-packages/gnuradio/usrp2.py", line 499,
> > in set_decim
> > return _usrp2.usrp2_source_32fc_sptr_set_decim(self, *args, **kwargs)
> >
> > TypeError: usrp2_source_32fc_sptr_set_decim() takes exactly 2 arguments (1
> > given)
> >
> > do you have any idea about the origin of this problem? Thank you in
> > advance.
> >
> >
> >
> >
> >
> >
> > On Mon, Apr 06, 2009 at 04:29:20PM -0300, Tiago Rogério Mück wrote:
> >
> >> / Updated from the trunk and I'm not getting that msg anymore./
> >> / /
> >> / Everything seems to be ok now./
> >>
> >
> > Glad to hear it! Thanks for letting us know.
> >
> > Eric
> >
> >
>