Re: [Discuss-gnuradio] BBN 802.11b updated: Barker spreading works

[Eric Blossom]

On Sun, Jun 14, 2009 at 07:45:32PM -0700, Colby Boyer wrote:
> Hey All,
> 
> I fixed the code in the pkt.py file so that DSSS with the barker code now
> works.  The main issue was the length of the barker interpolation filter was
> way too short (like 8).  I changed it so that it is now sample per baud *
> 11.  Additionally the barker sequence needs to be time reversed on the
> receive side so that the correct match filter is formed. Otherwise the nice
> autocorrelation properties of barker will go away.
> 
> I am only able to test it using the test script with a channel filter and
> gaussian noise and so far it has been a success there with both 1 and 2 Mbps
> modulation rates.  Can someone test with USRP2?  Also the BER seems to be
> much better as compared to just the RRC filter.  Hopefully this will make
> TX/RX much more robust.
> 
> The code is uploaded to the CGRAN svn under the branch/usrp2_version in the
> bbn project directory.
> 
> Cheers,
> Colby Boyer


Thanks, Colby!