GNU Radio/USRP on the WINLAB ORBIT Nodes

29 April 2009

James Sugrim

Rob Miller

The Story

• Software Defined Radio (SDR) progress

• Theory Simulation Experimentation

The GoalFamiliarity with WINLAB SDR resources.

(GNU Radio / USRP)

The Show So Far.

• Getting Started– Where the USRPs are located– Building your own image

• GNU Radio/USRP Overview

• Code Development

• Demonstration

Where the radios are…In the “big” grid the following

nodes have USRPs:

[1,2],[1,19],[20,19],[10,11],[20,2],[5,5],[5,15],[15,5],[15,15]

and USRP2s:

[18,3],[3,18]

In the Sandboxes, SB5 has USRPs on nodes:

[1,1],[1,2]

Not to scale

Imaging SB5(or the grid for that matter)

• There are reference images that are coupled with GNU Radio software, the most recent is named

gnuradio-3.1.ndz• Utilizing the omf (or orbit) facility we can bring up nodes

that have the software ready to be run.Command Syntax:

> omf load NodeList ImageName Where ImageName is the Image of interest, and NodeList is specified as a bracketed, comma delimited list (e.g. [1,1],[1,2],…). Keywords like all can be substituted for a list.

Example: To load the GNU Radio image onto Orbit nodes [1,2] and [20,19], use: > omf load [[1,2],[20,19]] gnuradio-3.1.ndz

www.orbit-lab.org/wiki/Documentation/SupportedImages

Grow your own.(Not recommended)

• If the stock versions are not what you’re looking for you can build your own image.

• There is an apt package name gnuradio, don’t use it.

• These additional sources were needed in the apt-list:

• These additional package may be necessary:

• It should be noted that the baseline image is based on debian (and not ubuntu)

• If you check out sources from SVN there is an additional step that precedes running ./configure; ./bootstrap preconfigures configure?

sdccboost-buildwx-commonlibqt3-mt-devlibgsl0-devGuilelibcomedi-0.7.22

deb http://gnuradio.org/ubuntu stable main contrib deb-src http://gnuradio.org/ubuntu stable main deb http://ftp.at.debian.org/debian/ etch main non-free contrib

ssh2 – X11 exportslocales Pythonbuild-essentialsauto-makesubversion

So Happy Together…• GNU Radio

Software “blocks” that run on the GPP

• Universal Software Radio Peripheral (USRP)Channelizer, DUCs/DDCs, Interpolator/Decimator

• RF DaughterboardsRF Interface

Enter the USRP• Universal Software Radio Peripheral (USRP)

– ADC 64 Msps (4)– DAC 128 Msps (4)– USB 2.0 Interface*– Small FPGA†

* Bottleneck: 8 MHz, 16-bit complex samples† Loads bitfile from the GPP

USRP2

• Uses same RF Daughterboards as USRP

• Gigabit Ethernet

• 100 Msps ADC (2)

• 400 Msps DAC (2)

• Larger FPGA

• SD card reader

RF Daughterboards• Basic RX

Receiver for use with external RF hardware

• Basic TXTransmitter for use with external RF hardware

• RFX24002.3-2.9 GHz Transceiver, 50+mW output

• RFX900800-1000MHz Transceiver, 200+mW output

• RFX400400 MHz - 500 MHz Transceiver, 100+mW output

• XCVR24502.4-2.5 GHz and 4.9 to 5.85 GHz Dual-band Transceiver,

100+mW output on 2.4 GHz, 50+mW output on 5GHz

Daughterboard DeploymentNode USRP USRPCoordinate Side A Side B

(1,2) FLEX-400 FLEX-2400(1,19) FLEX-400 FLEX-2400(20,19) FLEX-400 FLEX-2400(10,11) FLEX-400 FLEX-2400(20,2) FLEX-400 RFX-2400(15,5) FLEX-900 RFX-2400(15,15) XCVR-2450 RFX-2400(5,15) FLEX-900 FLEX-2400(5,5) XCVR-2450 RFX-2400

(18,3)* XCVR-2450 -(3,18)* XCVR-2450 -

SB5(1,1) Basic TX/RX -SB5(1,2) Basic TX/RX -

*USRP2

• Signal processing ‘blocks’– Implemented in C++ but callable from python

• Program development– ‘Glue’ together existing blocks in python

https://radioware.nd.edu/documentation/a-dictionary-of-the-gnu-radio-blocks

– Build your ownhttps://radioware.nd.edu/documentation/advanced-gnuradio

Simple Python Example

Reference: www.joshknows.com

src0

src1

dst

#!/usr/bin/env python

from gnuradio import grfrom gnuradio import usrpfrom optparse import OptionParserfrom usrpm import usrp_dbid

u_source = usrp.source_c()u_sink = usrp.sink_c()

subdev_Ar = usrp.selected_subdev(u_source, (0,0))subdev_Br = usrp.selected_subdev(u_source, (1,0))subdev_At = usrp.selected_subdev(u_sink, (0,0))subdev_Bt = usrp.selected_subdev(u_sink, (1,0))

print "RX d'board %s" % (subdev_Ar.side_and_name(),)print "RX d'board %s" % (subdev_Br.side_and_name(),)print "TX d'board %s" % (subdev_At.side_and_name(),)print "TX d'board %s" % (subdev_Bt.side_and_name(),)

Simple USRP Example #1

File location: gr‑utils\src\python\usrp_print_db.py

import necessary modules

setup usrp as source and sink

specify subdevices

print out names

Simple USRP Example #2

self.u = usrp.source_c(decim_rate=options.decim)

self.dst = gr.file_sink(gr.sizeof_gr_complex, filename)

self.head = gr.head(gr.sizeof_gr_complex, int(options.nsamples))

self.connect(self.u, self.head, self.dst)

options.rx_subdev_spec = usrp.pick_rx_subdevice(self.u)

self.u.set_mux(usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec))

self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec)

input_rate = self.u.adc_freq() / self.u.decim_rate()

self.subdev.set_gain(options.gain)

r = self.u.tune(0, self.subdev, options.freq)

usrp head file sinkcomplex complex

File location: gr‑utils\src\python\usrp_rx_cfile.py

key excerpts from usrp_rx_cfile.py

Simple USRP Example #2

>> ./usrp_rx_cfile.py –R B –f 2410M –d 128 –N 500e3 myfile.dat

usrp head file sinkcomplex complex

File location: gr‑utils\src\python\usrp_rx_cfile.py

Goal: Collect 1 second of data at 2.41 GHz with a sample rate of 500 KHz. Use Node (1,19) in the ORBIT grid and store the data in myfile.dat– Decimation: 64 MHz/500 KHz = 128– 500 KHz x 1 second = 500e3 samples

Node USRP Side A USRP Side B(1,19) FLEX-400 FLEX-2400

Building the house block by block

• How-to-build-a-block– Develop C++ signal processing– Make callable from python (SWIG)– Test the block– Install and use the block

from gnuradio import myblock

Good starting pointsradioware.nd.edu/documentation/advanced-gnuradio

www.gnu.org/software/gnuradio/doc/howto-write-a-block.html

Demo – Sandbox 5• (1) benchmark_tx.py to usrp_fft.py

• (2) benchmark_tx.py to benchmark_rx.py

File locations: gr‑utils\src\python\usrp_fft.py gnuradio-examples\python\digital\benchmark_tx.py gnuradio-examples\python\digital\benchmark_rx.py

USRP Debug Tidbit

• uUuUuUUSRP Underruns:

Not enough samples are ready to send to USRP sink.

• uOuOuOUSRP Overruns:

USRP samples have been dropped because they weren't read in time.

Suggestions

• Log into the sandbox and play!

Relevant References

• www.ettus.com• www.gnu.org/software/gnuradio/• www.gnuradio.org• www.joshknows.com• radioware.nd.edu/documentation

– Dawei Shen tutorials moved here– Dictionary of GNU Radio blocks

• www.orbit-lab.org• www.gnu.org/software/gnuradio/doc/howto-write-a-block.html

Questions?

Extra Slides Follow

usrp.source_c ( int which_board,unsigned int decim_rate,

  int nchan = 1, int mux = -1,

int mode = 0 )

USRP boot sequenceWhen the USRP is powered up, it puts the AD9862 is a low power state, and blinks the led 3 times per second. The host (computer) detects a USB device 04b4:8613, and therefore knows it is an unconfigured FX2 device. The driver will now load a firmware into the FX2, and when it boots up, the host will now detect a different USB device of fffe:0002. Using a capability of the newly loaded FX2 firmware, the driver will now initialize the FPGA. Once that is done, boot is complete, and the device is ready for tuning

Reference: en.wikipedia.org/wiki/Universal_Software_Radio_Peripheral

Abstract

• Recent advancements in the area of Software Defined Radio (SDR) haveopened the door for researchers to complement theoretical findings andsimulations with real world experimentation. A very popular SDR, used inboth academia and industry, is the Universal Software Radio Peripheral(USRP). Much experimentation has been done using this SDR in conjunction with GNU Radio signal processing blocks. The primary focus of this talk is to get new users involved with the GNU Radio/USRP resources available at WINLAB. In this talk, we will discuss how to access and develop on these platforms. We will also provide a high level description of theUSRP architecture, and an overview of the steps involved in implementingsignal processing routines. Additionally, we will comment on lessonslearned regarding the installation of GNU Radio onto the WINLAB nodes.Links and references to more detailed documentation will also beprovided.