= 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 for recording in database file.
 4. spectrum_measurement: 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
}}}