Multi Channel Sample Processing & Visualization

In this example we'll boxplot the received signal strength from several USRP channels on the MIMO rack.

Hardware / software resources utilized

1) upto 16 USRPs on the grid's MIMO rack
2) controller node (ie. node21-1) imaged with ubuntu-14-04-64bit-uhd-003.010.001-gnu-3.7.10.ndz
3) OML - Orbit Measurement Library to record measurements into database
4) rf_hw_intf - application to configure a set of USRPs for receiving samples at a specified frequency, samples rate, gain, etc…
5) sigproc_avg_bw_pwr - application for processing received samples and writing in OML database

Receive multi channel signal for processing and plotting

1) From the grid console, image the controller node then turn on all the USRPs (on the MIMO rack) and the controller node.

nilanjan@.grid:~$ omf load -i nilanjan@.grid:~$  -t node21-1
nilanjan@.grid:~$ omf tell -a on -t [[21,1],[23,1..8]]

2) Set up tunneling via ssh from your local port 5100 to the grid.orbit-lab.org:5100

my_laptop> ssh -L 5100:grid.orbit-lab.org:5100 username@grid.orbit-lab.org

3) Verify that Webproxy is running (this is required for remote web based streaming)

nilanjan@.grid:~$ run-websock 5100 localhost:5101 --daemon
WebSocket server settings:
  - Listen on :5100
  - Flash security policy server
  - No SSL/TLS support (no cert file)
  - Backgrounding (daemon)

4) Open a ssh session into the controller node and run the hardware interface application to start streaming the receiver.

root@node21-1:> ./rf_hw_intf --conf "mimo1.xml,/devices/mimo_rx" --rx-only --cmd-port 5111

5) Open another ssh session into the controller node and run the sample processing application. This application measures the average bandwidth power of the received samples and writes the measurements into the OML database.

root@node21-1> ./sigproc_avg_bw_pwr

6) Run the box plotting server on the console. This server will query measurements from the OML database and forward to webpage display.

nilanjan@.grid:~$ box-plot-server --port 5101 --file /var/lib/oml2/measured_avg_bw_pwr.sq3

7) Finally if everything is working correctly, the measured power across different channels can be view from a Chrome browser - ​click me :)