Re: [Discuss-gnuradio] complex examples

[Jim Lindstrom]

On 9/20/05, Eric Blossom <address@hidden> wrote:

> Any thoughts?

Long ago, in a galaxy far far away, I built a state-chart
compiler and runtime system that was used as part of the real-time
control in a line of secure phones.  Besides the state-chart
abstraction, it also included hierarchical blocks with unidirectional
typed message ports.  This was based on the "Real Time Object-Oriented
Modeling" (ROOM) ideas described in a book of the same title by Selic,
Gullekson and Ward.   Sometimes it seemed like more structure that I
wanted.  Being able to send a message to anybody you can see is
sometimes very helpful.

Eric, I think I'm interested in a more structured system than perhaps
you are.  What I'm interested in is a control framework where each
block has either (A) one or more control ports or (B) a single message
queue.  In the case of the control ports, I am envisioning
directed connections between control ports.  In the case of a
single message queue, you could go either publish/subscribe (broadcast)
or directed msgs (with some sort of recipient ID).  I don't really
like the more ad-hoc solution of having a heterogenous collection
blocks built from different abstractions.  The more abstractions,
the more code required to support them.

Before spending any work on the idea, I am very interested in seeing
how people are already trying to solve problems of control messaging
with GNU Radio or other SDR frameworks.  There's the case of
block-to-block control (maybe a downstream block knows that the
waveform is doing frequency hopping and publishes the new frequency to
an upstream demodulator, for instance).  There's also the case of
external application-to-block control if you try to do something fancy
like combining a COTS stack with a GNU Radio PHY layer.

So, again... Before embarking on building such a framework, I think it
would be wise to try to find some folks with experience with this sort
of thing, either in the form of code available, or just in the form of
lessons learned the hard way..  Anybody??

To jump ahead, I guess I was suggesting that perhaps this solution
sounds like a good candidate for state machines as the underlying model
since there are already FSM frameworks available and they give you an
event/message passing/queuing/handling framework for free essentially.

jbl