Re: [Discuss-gnuradio] MAC layer questions

[Andre Puschmann]

On 07/01/2011 03:16 AM, Morgan Redfield wrote:
> Hi,
> 
> I've been working on building a CSMA/CA MAC for the past couple of
> weeks. I built it in Python, and used ofdm/tunnel.py as a guide. It's
> working now, but I don't think it's very efficient. I ended up having
> to relax a lot of timing parameters to get it working, so my
> throughput is pretty bad. I also get a lot of dropped packets. I think
> this is also because my timing isn't very accurate, and I end up with
> more collisions than I would expect.
> 
> I was wondering if anyone else had had any luck building a CSMA/CA
> MAC. I saw a few posts on the mailing list from several years ago
> about people who were working on it, but I don't see any example code
> anywhere. I also checked out CMUmacs on CGRAN, but that relies on a
> deprecated version of GNURadio.
> 
> Is my best bet to rewrite the MAC as a block in C++? Can anyone tell
> me what kind of speedup that's likely to get me?
> 
> Thanks,
> Morgan Redfield

Hi Morgan,

we are also working on a CSMA/CA MAC here using a SDR software called
Iris (I know that's the GNU radio list but problems are pretty much the
same in terms of timing). The implementation is still not perfect but we
got some nice results already.

May I ask you about the throughput of your system? I would really like
to compare them with our setup.

There is also another paper titled "An IEEE 802.11 MAC Software Defined
Radio Implementation for Experimental Wireless Communications and
Networking Research" which might be of interest for you.


Regards,
Andre


-- 
André Puschmann
Ilmenau University of Technology, Integrated Communication Systems Group
Phone: +49 3677 69-4132, Fax: +49 3677 69-1614
Email: address@hidden, Web: http://www.tu-ilmenau.de/ics
Office: Zuse Building, room 1071