Re: [Discuss-gnuradio] packet interarrival time

[Eric Blossom]

On Sat, Feb 20, 2010 at 01:43:24PM -0800, Veljko Pejovic wrote:
> I narrowed down the problem to this:
> 
> - In a standard benchmark_rx.py example from "digital" immediately
> after a packet is received the callback is triggered.
> 
> - In the ofdm case the the callback is triggered in groups separated
> by one second. So, if a sender sends a bunch of packets they will be
> buffered at the receiver (or perhaps at the sender?) and then the
> callback is issued sequentially for each of the packets in that group.
> Then, after a one second gap, another group of packets will be
> processed.
> 
> I checked the times of when "msg = self.rcvd_pktq.delete_head()" from
> ofdm.py is called and confirmed the above. Sometimes it waits for a
> second, and then it gets fired in a number of bursts corresponding to
> the number of pkts received.
> 
> Is there a way to force the receiver to wait for less then a second?
> Or is it the sender that buffers the packets? Although, it doesn't
> look like that from my measurements.
> 
> Thanks,
> Veljko

Are you sure that the transmitter is transmitting continuously, or is
it transmitting a group of packets once per second?

The simplest way to check this is to watch with a spectrum analyzer.

It's unlikely that there is any code in the receiver that is holding
back the processing of the packets.

Eric