On Fri, Feb 12, 2010 at 12:52:00PM -0800, Veljko Pejovic wrote: > Hi, > > I'm using two USRP2 with XCVR2450s, gnuradio 3.2.2 and Ubuntu 9.10. > > I ran the benchmark_tx/rx example from gnuradio-examples/ofdm and > measured packet inter-arrival times at the receiver. I also modified > the sender to wait for some time (like 200ms) between individual > packets. I also set the msg queue size to one. In python code I'm > printing a bunch of time.time() values to keep the timeline of the > events. > > What I observe is the following: > - inter-departure times are constant, the packet size and the bit rate > would of course influence the time spent sending, but that would still > be a relatively small value. > - at the receiver, most packets are received with the inter-arrival > time comparable to the inter-departure time at the sender, however, > occasionally I would see a huge lag between two consecutive packets > (almost a second). > > I read the NSDI'09 paper > (http://portal.acm.org/citation.cfm?id=1558984) that talks about USRP1 > performance, however, what I observe is way higher delay and it's > USRP2. Thus, I'm sure that there's something I can do to fix this > delay. Any hints?
Are packets getting dropped? Is the USRP2 on a dedicated ethernet port? Is there a switch between the host and the USRP2? Eric _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
