[Discuss-gnuradio] Data transmission in bursts using uhd

[Tobias Schmid]

Hello,

I implemented a selective repeat ARQ-protocol using the USRP2.
Up til now I used the USRP2 driver.
Now I want to upgrade my system to use UHD.
I upgrade the to hosts, the FPGA image and the firmware of my USRP2s.
Now the continous data transmission works fine.
But the bursty protocol communication doesn't work.

I used this code form the ursp sink in the downstream part of the transmitter:

if not self.usrp:
  self.usrp2_sink = uhd.single_usrp_sink(
  device_addr="addr=192.168.10.2",
  io_type=uhd.io_type_t.COMPLEX_FLOAT32,
  num_channels=1,
  )
  self.usrp2_sink.set_samp_rate(self.output_samp_rate)
  self.usrp2_sink.set_center_freq(self.center_frequency, 0)
  self.usrp2_sink.set_gain(self.tx_gain, 0)        
 else:
  self.usrp2_sink = usrp2.sink_32fc('eth1','')
  self.usrp2_sink.set_interp(self.usrp_interp_rate)
  self.usrp2_sink.set_center_freq(self.center_frequency)
             self.usrp2_sink.set_gain(self.tx_gain)

And this one for the usrp source for the resceiving part of the feedback 
channel in the transmitter of the overall system.

if not self.usrp:
   self.usrp_source = uhd.single_usrp_source(
   device_addr="addr=192.168.10.2",
   io_type=uhd.io_type_t.COMPLEX_FLOAT32,
   num_channels=1,
   )
   self.usrp_source.set_samp_rate(self.input_samp_rate)
   self.usrp_source.set_center_freq(self.center_frequency, 0)
   self.usrp_source.set_gain(self.rx_gain, 0)
   self.usrp_rate = self.input_samp_rate
 else:
   self.usrp_source = usrp2.source_32fc('eth1','')
   self.usrp_source.set_decim(self.usrp_decim_rate)
   self.usrp_source.set_center_freq(self.center_frequency)
   self.usrp_source.set_gain(self.rx_gain)
              self.usrp_rate = int(self.usrp_source.adc_rate() / 
self.usrp_decim_rate)     # sample rate from USRP

Do I have to do something in addition to make it work for bursty transmissions.

Furthermore I get an 'U' in terminal of the transmitter after each burst. Is 
this the same problem?

Thanks for your help.

Regards,

Tobias
 
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