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Working with USRP - Universal Software Radio Peripheral

Description

In this tutorial we'll use the 2 USRPs on Sandbox 3 to transmit and receive a single frequency over the air to demonstrate the use of Universal software Radio peripheral Hardware Drivers (UHD) which is used standalone to configure and enable the USRPs.

Hardware / Software Resources utilized

1. Sandbox 3 - consists of two nodes (node1-1 & node1-2). Each node has a USRP2 connect via Ethernet.
2. ubuntu-11-10-gnuradio.ndz: disk image loaded onto nodes. This image has all the precompiled - software required to configure the USRPs and analyze recorded data. The USRP2's interface with the node is already configured.
3. omf-5.2 / omf-5.3: used to image to nodes
4. octave: GNU version of MATLAB

Set up

• To get started first make a reservation on the ​Orbit Scheduler for using Sandbox 3

• After logging into sandbox 3 console, make sure both nodes are turned off

  nilanjan@console.sb3:~$ omf-5.2 tell offh all
  

• Verify state of node before continuing. Make sure all nodes are in the POWEROFF state.

  nilanjan@console.sb3:~$ omf-5.2 stat
  

• Image both nodes

  nilanjan@console.sb3:~$ omf-5.3 load -i ubuntu-11-10-gnuradio.ndz -t node1-1.sb3.orbit-lab.org,node1-2.sb3.orbit-lab.org
  

• After nodes are imaged, verify that nodes are in POWEROFF state. Otherwise issue the following to turn them off for a reboot

  nilanjan@console.sb3:~$ nilanjan@console.sb3:~$ omf-5.2 tell offh all
  

• Turn nodes back on and verify they are in POWERON state before proceeding

  nilanjan@console.sb3:~$ nilanjan@console.sb3:~$ omf-5.2 tell on all
  

Usage

• Once nodes are imaged, ssh into each node. Use the USRP2 on node1-1 as the transmitter and USRP2 on node1-2 as receiver.
  ssh into node1-1

  nilanjan@console.sb3:~$ ssh root@node1-1
  root@node1-1:~# cd uhd/host/build/examples/
  

ssh into node1-2

nilanjan@console.sb3:~$ ssh root@node1-2
root@node1-1:~# cd uhd/host/build/examples/

• The directory content should look like the following in both nodes

  root@node1-1:~/uhd/host/build/examples# ls
  benchmark_rate       latency_test      rx_samples_to_file  test_pps_input        tx_waveforms
  CMakeFiles           Makefile          rx_samples_to_udp   tx_bursts
  cmake_install.cmake  network_relay     rx_timed_samples    tx_samples_from_file
  CTestTestfile.cmake  rx_multi_samples  test_messages       tx_timed_samples
  

• Once inside the node verify that the node can talk to the USRP

  root@node1-1:~/uhd/host/build/examples# uhd_find_devices
  

• It should return something like the following:

  root@node1-1:~/uhd/host/build/examples# uhd_find_devices
  linux; GNU C++ version 4.6.1; Boost_104601; UHD_003.004.003-0-unknown
  
  --------------------------------------------------
  -- UHD Device 0
  --------------------------------------------------
  Device Address:
      type: usrp2
      addr: 192.168.10.2
      name:
      serial: 1232
  

• Probe the device

  root@node1-1:~/uhd/host/build/examples# uhd_usrp_probe
  linux; GNU C++ version 4.6.1; Boost_104601; UHD_003.004.003-0-unknown
  
  -- Opening a USRP2/N-Series device...
  -- Current recv frame size: 1472 bytes
  -- Current send frame size: 1472 bytes
    _____________________________________________________
   /
  |       Device: USRP2 / N-Series Device
  |     _____________________________________________________
  |    /
  |   |       Mboard: USRP2-REV4
  |   |   hardware: 1024
  |   |   mac-addr: 00:50:c2:85:34:d0
  |   |   ip-addr: 192.168.10.2
  |   |   gpsdo: none
  |   |   serial: 1232
  |   |
  |   |   Time sources: none, external, _external_, mimo
  |   |   Clock sources: internal, external, mimo
  |   |   Sensors: mimo_locked, ref_locked
  |   |     _____________________________________________________
  |   |    /
  |   |   |       RX DSP: 0
  |   |   |   Freq range: -50.000 to 50.000 Mhz
  |   |     _____________________________________________________
  |   |    /
  |   |   |       RX DSP: 1
  |   |   |   Freq range: -50.000 to 50.000 Mhz
  |   |     _____________________________________________________
  |   |    /
  |   |   |       RX Dboard: A
  |   |   |   ID: XCVR2450 (0x0061)
  |   |   |     _____________________________________________________
  |   |   |    /
  |   |   |   |       RX Subdev: 0
  |   |   |   |   Name: XCVR2450 (0x0061)
  |   |   |   |   Antennas: J1, J2
  |   |   |   |   Sensors: lo_locked, rssi
  |   |   |   |   Freq range: 2400.000 to 6000.000 Mhz
  |   |   |   |   Gain range LNA: 0.0 to 30.5 step 15.0 dB
  |   |   |   |   Gain range VGA: 0.0 to 62.0 step 2.0 dB
  |   |   |   |   Connection Type: IQ
  |   |   |   |   Uses LO offset: No
  |   |   |     _____________________________________________________
  |   |   |    /
  |   |   |   |       RX Codec: A
  |   |   |   |   Name: ltc2284
  |   |   |   |   Gain Elements: None
  |   |     _____________________________________________________
  |   |    /
  |   |   |       TX DSP: 0
  |   |   |   Freq range: -250.000 to 250.000 Mhz
  |   |     _____________________________________________________
  |   |    /
  |   |   |       TX Dboard: A
  |   |   |   ID: XCVR2450 (0x0060)
  |   |   |     _____________________________________________________
  |   |   |    /
  |   |   |   |       TX Subdev: 0
  |   |   |   |   Name: XCVR2450 (0x0060)
  |   |   |   |   Antennas: J1, J2
  |   |   |   |   Sensors: lo_locked
  |   |   |   |   Freq range: 2400.000 to 6000.000 Mhz
  |   |   |   |   Gain range VGA: 0.0 to 30.0 step 0.5 dB
  |   |   |   |   Gain range BB: 0.0 to 5.0 step 1.5 dB
  |   |   |   |   Connection Type: QI
  |   |   |   |   Uses LO offset: No
  |   |   |     _____________________________________________________
  |   |   |    /
  |   |   |   |       TX Codec: A
  |   |   |   |   Name: ad9777
  |   |   |   |   Gain Elements: None
  

If the commands uhd_find_devices & uhd_usrp_probe return No UHD Devices Found, please refer to the trouble shooting section.

• Set up node1-1 to transmit a single frequency sine wave with a frequency of 100k Hz sampled at a rate of 8 Msamples / second and modulated upto 5000MHz

  ./tx_waveforms --wave-freq 100e3 --wave-type SINE --freq 5000e6 --rate 8e6
  

Troubleshooting

• uhd_find_devices & uhd_usrp_probe return No UHD Devices Found