Draft-AN-445

Application Note Number

AN-445

Abstract

This Application Note provides a comprehensive guide for building and installing the open-source toolchain for the USRP (UHD and GNU Radio) from source code on a Linux platform. UHD is fully supported on Linux using the GCC compiler, and should work on most major Linux distributions. In this document, the Ubuntu 22.04 and Ubuntu 20.04 distributions specifically are discussed.

Devices

This document applies only to the USRP X300, X310, B200, B210, B200mini, N200, and N210 devices. The E310 and E312 devices are embedded devices which are fundamentally different from the other non-embedded devices. They are not addressed in this document.

Update and Install dependencies

Before building UHD and GNU Radio, you need to make sure that all the dependencies are installed.

The following commands will install all the required dependencies. Before running them, you should ensure that the "Main" and "Universe" repositories are enabled in "Software Sources".

Next, on a terminal screen, run:

   sudo apt-get update

Once the system has been updated, then install the required dependencies below.

Focal Fossa (20.04) through Lunar Lobster (23.04)

GNU Radio version 3.8.x with Python 3 support:

sudo apt install git cmake g++ libboost-all-dev libgmp-dev swig python3-numpy \
python3-mako python3-sphinx python3-lxml doxygen libfftw3-dev \
libsdl1.2-dev libgsl-dev libqwt-qt5-dev libqt5opengl5-dev python3-pyqt5 \
liblog4cpp5-dev libzmq3-dev python3-yaml python3-click python3-click-plugins \
python3-zmq python3-scipy python3-gi python3-gi-cairo gir1.2-gtk-3.0 \
libcodec2-dev libgsm1-dev libusb-1.0-0 libusb-1.0-0-dev libudev-dev

GNU Radio version 3.9.x in addition to above requires:

sudo apt install pybind11-dev python3-matplotlib libsndfile1-dev \
libsoapysdr-dev soapysdr-tools python3-pygccxml python3-pyqtgraph

GNU Radio version 3.10.x and the 'main' branch in addition to above require:

sudo apt install libiio-dev libad9361-dev libspdlog-dev python3-packaging python3-jsonschema

If the installation of the dependencies completes without any errors, then you can proceed to build and install UHD and GNU Radio.

Building and installing UHD from source code

UHD is open-source, and is hosted on GitHub. You can browse the code online at the link below.

• UHD repository on GitHub

If you want to use GNU Radio with a USRP, install the UHD package from source using the following instructions. UHD sits at the same level as GNU Radio as an independent driver, which gr-uhd references. So if you want gr-uhd enabled, you FIRST must clone and install UHD.

For this example, we will start in the home directory to parallel the steps for installing GNU Radio from source.

cd $HOME/

Clone the code into your home directory:

git clone https://github.com/EttusResearch/uhd.git
cd $HOME/uhd

Note: In the following command, change v4.6.0.0 to some other branch or tag if you want to build a different version.

git checkout v4.6.0.0

Note: Unlike most GNU Radio build processes, UHD builds under the host directory.

cd host
mkdir build
cd build

Note: In the following command, we will use -DCMAKE_INSTALL_PREFIX=/usr/local to install UHD into the same prefix as GNU Radio.

   cmake -DCMAKE_INSTALL_PREFIX=/usr/local ../

Note: In the following command, if your computer's CPU has multiple cores, you can use the argument -j# to speed compilation;
e.g., make -j3 will use 3 threads in the build. Specify at most one less than the number of CPU cores so the system does not appear to 'freeze' during the build. If not specified, then a single thread is used for the build.

make -j3
make test
sudo make install
sudo ldconfig

Finally, make sure that the LD_LIBRARY_PATH environment variable is defined and includes the folder under which UHD was installed. Most commonly, you can add the line below to the end of your $HOME/.bashrc file:

   export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

For this change to take effect, you will need to close the current terminal window, and open a new terminal.

At this point, UHD should be installed and ready to use. You can quickly test this, with no USRP device attached, by running uhd_find_devices. You should see something similar to the following.

[INFO] [UHD] linux; GNU C++ version 11.4.0; Boost_107400; UHD_4.6.0.HEAD-0-g50fa3baa
No UHD Devices Found

You can now download the UHD FPGA Images for this installation.

sudo uhd_images_downloader

Configuring USB

On Linux, udev handles USB plug and unplug events. The following commands install a udev rule so that non-root users may access the device.

cd $HOME/uhd/host/utils
sudo cp uhd-usrp.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules
sudo udevadm trigger

Configuring Ethernet

For USRP devices that use Ethernet to connect to the host computer, such as the N200, N210, X300, X310, set a static IP address for your system of 192.168.10.1, with a netmask of 255.255.255.0. The default IP address of the USRP is 192.168.10.2, with a netmask of 255.255.255.0. You should probably set the IP address using the graphical Network Manager. If you set the IP address from the command line with ifconfig, Network Manager will probably overwrite these settings.

Connect the USRP

The installation of UHD should now be complete. At this point, connect the USRP to the host computer.

If the interface is Ethernet, then open a terminal window, and try to ping the USRP with "ping 192.168.10.2". The USRP should respond to the ping requests.

If the interface is USB, then open a terminal window, and run "lsusb".
You should see the USRP listed on the USB bus with a VID of 2500. The PID should be:

• 0020 for B200
• 0021 for B200mini
• 0022 for B205mini

Also try running "uhd_find_devices" and "uhd_usrp_probe".

Thread priority scheduling

When UHD spawns a new thread, it may try to boost the thread's scheduling priority. If setting the new priority fails, the UHD software prints a warning to the console, as shown below. This warning is harmless; it simply means that the thread will retain a normal or default scheduling priority.

UHD Warning:
    Unable to set the thread priority. Performance may be negatively affected.
    Please see the general application notes in the manual for instructions.
    EnvironmentError: OSError: error in pthread_setschedparam

To address this issue, non-privileged (non-root) users need to be given special permission to change the scheduling priority. This can be enabled by creating a group usrp, adding your user to it, and then appending the line @usrp - rtprio 99 to the file /etc/security/limits.conf.

   sudo groupadd usrp
   sudo usermod -aG usrp $USER

Then add the line below to end of the file /etc/security/limits.conf:

   @usrp - rtprio  99

You must log out and log back into the account for the settings to take effect. In most Linux distributions, a list of groups and group members can be found in the /etc/group file.

There is further documentation about this in the User Manual at the link below.

• Threading Notes section of the User Manual

Building and installing GNU Radio from source code

GNU Radio is open-source, and is hosted on GitHub. You can browse the code online at the link below.

• GNU Radio repository on GitHub

The development of GNU Radio is very fast-paced, but the GNU Radio Wiki is kept up to date with all changes.

• For GNU Radio 3.9, 3.10, and the Main branch, click here.
• For GNU Radio 3.8, click here.