= 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. The UHD (UniversalSoftwareRadioPeripheral Hardware Driver) is used to communicate with the USRPs. This driver is used standalone to configure and enable the USRP for communication.

== 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.
 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 [https://www.orbit-lab.org/schedule/ 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.[[BR]]
 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 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
}}}