Re: [Discuss-gnuradio] Talking about DSP and SDR [Was: On tunnel.py]

[Tom Rondeau]

On Sat, Mar 30, 2013 at 11:35 AM, Brian Padalino <address@hidden> wrote:
> On Sat, Mar 30, 2013 at 9:54 AM, Tom Rondeau <address@hidden> wrote:
>>
>> To move on in this topic, Alex brings up an interesting point. One of
>> the reasons for this mailing list is to discuss signal processing,
>> SDR, algorithms, etc. Hopefully in a way that helps us improve either
>> GNU Radio itself of our use of GNU Radio tools and blocks. I would
>> really like to see more of this.
>>
>> The problem is that in the past, every now and then, someone tries to
>> do this. But it never seems to work or end very satisfactorily. The
>> mailing list structure seems like it doesn't lend itself to properly
>> discuss signal processing in a useful way.
>>
>> To start with, we need to start passing around flowgraphs (preferably
>> GRC) so that we can all see what's being discussed. There is also the
>> gnuradio.org wiki that people could use to build pages that better
>> describe the problem, idea, or suggestion. That format can handle
>> images, better embedding of formulas, and file attachments (include
>> data sets that are too big to mail out).
>>
>> I would love to see someone take this on as a challenge to try to spur
>> on more discussion about communications. Over the past few years,
>> we've also gotten much better about using Git and tools like github to
>> submit patches and fixes. So I would encourage everyone to use the
>> available tools to help us all better communicate with each other.
>
>
> As I am here mainly for the algorithm talk, this sounds like a great idea.
> Are you envisioning a new Signal Processing and SDR section to the main
> page?  Some of the topics I think that would be a good start are:
>
>   0. Understanding the (insert commercial standard here) MAC and PHY
>   1. Frequency calibration using your local GSM station
>   2. The near-far problem and how hardware still matters with software
> defined radios
>   3. Synchronization and frequency offset
>   4. Modulations and channel filtering
>   5. Forward Error Correction
>   6. Simulation within GNU Radio
>   7. OFDM Demystified
>   8. Diversity in Space, Time, and Frequency
>   9. Wireless Channels and how to mitigate their effects
>
> I am pretty sure most, if not all, of the topics are covered somewhere in
> the GNU Radio code base or can be easily explained by some people on the
> mailing list.
>
> Also, I am sure most everyone has seen it, but Charan Langton's website:
>
>   http://complextoreal.com/tutorials/
>
> has some excellent, freely available tutorials that explain the theory and
> math of a slew of communication related topics.  It would be great to link
> those tutorials with a real implementation in GNU Radio.
>
> I think some good candidates for the first topics might be all the new OFDM
> work as well as the simulation aspect of GNU Radio so more of the user base
> feels empowered by the software without feeling like they need hardware to
> be able to use GNU Radio.
>
> So what do you think should be first?  What would you like to see?  I know
> you've blogged about GNU Radio updates.  Should those be topics discussing
> algorithms and pragmatic GNU Radio?
>
> I think you said it best:
>
>   "It's not easy, but communications is not easy. In fact, it's very, very
> hard."
>
> Seems to apply to every aspect of communication and is not limited to
> wireless.
>
> Brian

Hi Brian,

Yes, having a wiki space to describe and discuss these issues was
exactly my thinking. I use my personal blog (www.trondeau.com/blog) to
discuss some things that I've done with GNU Radio, but having a space
on gnuradio.org where people can pose questions, answers, tutorials,
etc. should be a real boon to the community.

I love the idea of taking those tutorials you pointed to and making
GNU Radio applications that showcase them. I suggested a similar
concept of using the "DSP Tips and Tricks" section of IEEE Sig. Proc.
Magazine a while ago:
http://www.trondeau.com/blog/2011/5/16/dsp-tips-and-tricks.html. They
are small, 2-page papers that show off some small DSP tip or trick (as
the name would imply) that is simple to express and therefore work up
in GNU Radio.

Students learning comms theory and DSP could benefit a lot from either
developing these or having them available for study.

Now the question is: who wants to start working on this concept?

I'd suggest that Brian start formatting the page based on the list he
put above, but I think we might be better served by having someone
come up with a full page for something, like the OFDM model you
mentioned, so we can get a feel for how this will go and how the pages
will eventually look.

Tom