[Discuss-gnuradio] A Question on Packet Processing

[Tim Meehan]

Hello All,

I have been looking into using gnuradio for packet processing.  I am
having a hard time understanding exactly how to make this work.

What I would like to do is send out packets of around 200 symbols or
so.  I think I understand how to do this at the transmit end.

What I am stuck on is how to build a receive flowgraph that detects
packets and sends signals to processing blocks further down the line.
For example, I would want to detect the start of a packet and then
send a signal to a downstream viterbi decoder to "reset" back to an
initial state.   I might also want to select one of N different blocks
depending on what type of packet is detected.

I have been looking at the examples in gnuradio-examples/python/channel-coding/

In these examples the flowgraph is set up from scratch for each packet.
This method works fine but there seems to be a lot of overhead with
setting up the flowgraph (it takes a LONG time to run lots of
packets).  Perhaps the answer is to get away from python?

I have taken a look at the examples that use pkt.py but I am not sure
how to use things like gr-trellis with them.

Any hints would be much appreciated.

Tim