= Spectrum sensing with USRP2 =

== Description ==
In this tutorial we'll use the USRPs on the grid for FFT-based spectrum sensing. Each USRP (centered on a frequency with specified bandwidth) will collect data into an OML server for post processing. For details on available USRP2s on the grid, please see [http://www.orbit-lab.org/wiki/Documentation/USRP2_hw_map available USRP2 HW].

== Hardware / Software Resources utilized ==
 1. Grid nodes with 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. spectrum: application on node to set up & collect data from USRP2 and send to OML server / local file for recording in database file.
 4. spectrum_console: application on console to configure & initiate spectrum sense application on node.
 5. Octave / sqlite3: for post processing data measured spectrum sense data.

== Set up ==
 * To get started first make a reservation on the [https://www.orbit-lab.org/schedule/ Orbit Scheduler] for using the Grid.

 * After logging into grid console, make sure all nodes are turned off
{{{
nilanjan@console.grid:~$ omf-5.3 tell -a offh -t system:topo:n210
}}}

 * Verify state of node before continuing. Make sure all nodes are in the POWEROFF state.
{{{
nilanjan@console.grid:~$ omf-5.3 stat
}}}

 * Image nodes
{{{
nilanjan@console.grid:~$ omf-5.3 load -i ubuntu-11-10-gnuradio.ndz -t system:topo:n210
}}}

 * After nodes are imaged, verify that nodes are in POWEROFF state. Otherwise issue the following to turn them off for a reboot
{{{
nilanjan@console.grid:~$ omf-5.3 tell -a offh -t system:topo:n210
}}}

 * Turn nodes back on and verify they are in POWERON state
{{{
nilanjan@console.grid:~$ omf-5.3 tell -a on -t system:topo:n210
}}}

  * Before proceeding, download the [http://www.orbit-lab.org/attachment/wiki/Documentation/GNURadio/Tutorials/FFTSpectrum/spectrum_console.cpp spectrum console application code] to your local directory. This is the application that will invoke the application to configure the USRP on the nodes.
{{{
nilanjan@console.grid:~/UHD/SPECTRUM/w$ wget http://www.orbit-lab.org/raw-attachment/wiki/Documentation/GNURadio/Tutorials/FFTSpectrum/spectrum_console.cpp
}}}

 * Compile the application code.
{{{
nilanjan@console.grid:~/UHD/SPECTRUM/w$ g++ spectrum_console.cpp -lboost_program_options-mt -loml2 -o spectrum_console
}}}
== Usage ==