# About the simple\_mac.py in bbn80211 **URL:** \ **Category:** GNU Radio\ **Created:** [October 16, 2009, 12:05am UTC](https://www.ruby-forum.com/t/about-the-simple-mac-py-in-bbn80211/177377 "2009-10-16T00:05:28Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![chenchen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c77e96/32.png) [@chenchen](https://www.ruby-forum.com/u/chenchen)\ **Post date:** [October 16, 2009, 12:05am UTC](https://www.ruby-forum.com/t/about-the-simple-mac-py-in-bbn80211/177377/1 "2009-10-16T00:05:28Z")
Hi, I download the bbn80211, and want to use the simple\_mac.py to do some experiment. But this code is not compile with the new version of GNU Radio, thus cause many errors. Does anyone do the modification of this script so that it can work with the new GNU Radio version? Thank you very much. Best, Chen C. ---
**Author:** ![chenchen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c77e96/32.png) [@chenchen](https://www.ruby-forum.com/u/chenchen)\ **Post date:** [October 16, 2009, 2:56am UTC](https://www.ruby-forum.com/t/about-the-simple-mac-py-in-bbn80211/177377/2 "2009-10-16T02:56:24Z")
Can you describe what errors you are getting? - Miklos ---
**Author:** ![chenchen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c77e96/32.png) [@chenchen](https://www.ruby-forum.com/u/chenchen)\ **Post date:** [October 16, 2009, 3:26pm UTC](https://www.ruby-forum.com/t/about-the-simple-mac-py-in-bbn80211/177377/3 "2009-10-16T15:26:15Z")
I believe this code was never updated to the blks2/hier\_block2 API. At least in the usrp2\_branch and my branch on CGRAN it hasn’t been. It may just take the same work that was done for the transmit and receive code to port it over (e.g. changing blks → blks2, hier\_block → hier\_block2, and the **init** call to specify the io signature). On Thu, Oct 15, 2009 at 8:52 PM, Miklos Christine [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > experiment. But this code is not compile with the new version of GNU Radio, > > [Discuss-gnuradio Info Page](http://lists.gnu.org/mailman/listinfo/discuss-gnuradio) – Doug G. removed\_email\_address@domain.invalid ---
**Author:** ![chenchen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c77e96/32.png) [@chenchen](https://www.ruby-forum.com/u/chenchen)\ **Post date:** [October 16, 2009, 5:12pm UTC](https://www.ruby-forum.com/t/about-the-simple-mac-py-in-bbn80211/177377/4 "2009-10-16T17:12:47Z")
Since I have made changed in the bbn\_80211b\_rx.py and bbn\_80211b\_tx.py (also some related script such as bbn\_80211b.py and bbn\_80211b\_pkts.py) as you mention: blks-blks2, hier-block-\>hier\_block2, and the **init** call. (modifiy the original version since it is for usrp1). It can run but the receiver can not show anything. receiver side: ./bbn\_80211b\_rx.py -f 2412M -d 24 -S 8 -g 35 transmitter side: ./bbn\_80211b\_tx.py -f 2412M -i 24 -S 8 So I am wondering if I modified the simple\_mac.py, it will cause the same problem? Does anyone make the bbn\_80211b\_rx.py and bbn\_80211b\_tx.py work on the usrp1? and also for simple\_mac.py? Thanks Chen On Fri, Oct 16, 2009 at 9:15 AM, Douglas G. \< ---
**Author:** ![chenchen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c77e96/32.png) [@chenchen](https://www.ruby-forum.com/u/chenchen)\ **Post date:** [October 16, 2009, 10:58pm UTC](https://www.ruby-forum.com/t/about-the-simple-mac-py-in-bbn80211/177377/5 "2009-10-16T22:58:11Z")
One thing to be aware of: the USRP1 does _not_ have sufficient bandwidth to the host PC to do real DSSS 802.11b. On the receive side they were able to get it ‘sort of’ working by simply accepting the aliasing that results from under-sampling. For transmitting/receiving between two USRP1’s - I believe the original BBN code simply took the DPSK-modulated sequence, and ran it through a RRC filter, without any spreading taking place - so the bandwidth of the USB link is no longer an issue. This mode allows the USRP1 to do 802.11-like networking - but it won’t inter-operate with regular 802.11 gear. I will also note that the original BBN code had a bug in the matched filter design (in bbn\_firdes\_barker.cc), it did not reverse the barker sequence (which makes the FIR filter/convolution operation the same as multiplying by the [forward] sequence). I have not checked in the fix to my branch, but the usrp2\_version branch achieves the sample thing, with the addition of a resampling block to make the FIR operation work on a lower data rate. Since it worked, I assume the error simply made the effective SNR worse - as it was with the USRP1 it could only receive very high SNR 1 and 2Mbps packets from commerical 802.11 gear. On Fri, Oct 16, 2009 at 10:30 AM, Chen C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > ./bbn\_80211b\_tx.py -f 2412M -i 24 -S 8 – Doug G. removed\_email\_address@domain.invalid ---
**Author:** ![chenchen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c77e96/32.png) [@chenchen](https://www.ruby-forum.com/u/chenchen)\ **Post date:** [October 30, 2009, 5:45am UTC](https://www.ruby-forum.com/t/about-the-simple-mac-py-in-bbn80211/177377/6 "2009-10-30T05:45:36Z")
Chen C. wrote: > Hi, > > I download the bbn80211, and want to use the simple\_mac.py to do some > experiment. But this code is not compile with the new version of GNU > Radio, > thus cause many errors. Does anyone do the modification of this script > so > that it can work with the new GNU Radio version? > > Thank you very much. > > Best, > > Chen C. hi,Chen C. would you send bbn80211 code to me,my poor net has problem when connected to the server.My mail address removed\_email\_address@domain.invalid. Thank you very much. ---
**Author:** ![chenchen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/c77e96/32.png) [@chenchen](https://www.ruby-forum.com/u/chenchen)\ **Post date:** [October 17, 2009, 10:19am UTC](https://www.ruby-forum.com/t/about-the-simple-mac-py-in-bbn80211/177377/7 "2009-10-17T10:19:28Z")
Hi, In your simple\_mac.py, do you change these things: flow\_graph-\>top\_block blks-\>blks2, hier\_block-\>hier\_block2? I think these are some differences between new and old version of GNU Radio. And the bbn code is for the old version of GNU Radio Thanks, Chen