Re: [Discuss-gnuradio] All software radio system

[Eric Blossom]

On Sun, Mar 05, 2006 at 05:20:48PM +1100, Jovan Mostanovski wrote:
> Hi group,
>       As part of my major uni project I'm using software radio to create a
> data communications network for long range HF transmission.

Sounds good.

> The problem is that to do make this system we only have 8 months, and it
> has become evident that there is too much work involved in this project
> when including all the real world testing.

> Not only that, but we need to start working right away, and waiting
> weeks to receive the USRP and other hardware required is no longer an
> option.

I suspect Matt can get you USRP's within a week.  
Money has a way of speeding up those global transportation problems ;)

> I've come up with the idea to implement the whole system in software
> initially, so that we can start working on it straight away, and this
> takes real world testing out of the equation, because it is impractical
> for us to test the system for transmissions between moving nodes
> situated hundreds of kilometers apart. Also, we are only undergrad
> students and just don't have the experience.
> 
> What I'm thinking of doing is something like this:
> 
> ----------    ---------------    --------------------    
> Protocol |--> |  Modulator  |--> | Freq conv to RF  |--> 
> ----------    ---------------    --------------------
> 
> -------------------------------     --------------------     ----------
> | Simulation of doppler shift  |--> |Freq conv to IF   |-->  | Demod  |
> | & multi path fading          |    |                  |     |        |
> --------------------------------    --------------------     ----------
> 
> etc etc.......
> 
> Each part would be designed as a GNU Radio block, hence reuseable for
> other application...

This sounds reasonable.  We currently don't have anything that
simulates fading channels and it would be great to add that to our
collection of blocks.

> What are your opinions on this approach?

How will you know if your simulation is correct and that your channel
simulator reflects some semblance of reality? [ The devil made me say it ;) ]

Eric