[Discuss-gnuradio] BBN 802.11b updated: Barker spreading works
From:
Colby Boyer
Subject:
[Discuss-gnuradio] BBN 802.11b updated: Barker spreading works
Date:
Sun, 14 Jun 2009 19:45:32 -0700
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.