My application works in a repeated on-off manner. The receiver USRP works in the following way:
1.The flowgraph starts. It runs for 5 second while collecting data and doing some online processing. Thereafter, the flowgraph stops.
2. I do some off-line processing with the stored data for the next 5 seconds 3. The flowgraph is restarted and step 1-2 are repeated.
The flowgraph looks like the following:
USRP Source --> Log power FFT --> Vector to stream --> File Sink.
However, the flow graph freezes from time to time. This freezing occurs once in every 5-10 trials. It is surprising since I hardly see any overrun in the receiver (I am running the USRP at 4 MS/s and performing 4096 point FFT). Besides, I have a python code that pings the USRP every time before starting the flowgraph.
I am using USRP N210, the latest GNUradio & UHD drivers, Ubuntu 12.04. Any suggestions on resolving this issue will be very appreciated.
-- Muhammad Nazmul Islam
Graduate Student Electrical & Computer Engineering Wireless Information & Networking Laboratory Rutgers, USA.