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OAI Build Procedures

[[TOC]]

This page is valid on tags starting from 2019.w09.

Overview

The OAI EPC and OAI 5GC are developed in distinct projects with their own documentation and are not further described here.

OAI softmodem sources, which aim to implement 3GPP compliant UEs, eNodeB and gNodeB can be downloaded from the Eurecom gitlab repository.

Sources come with a build script build_oai located at the root of the openairinterface5g/cmake_targets directory. This script is developed to build the oai binaries (executables,shared libraries) for different hardware platforms, and use cases.

The main oai binaries, which are tested by the Continuous Integration process are:

  • The LTE UE: lte-uesoftmodem
  • The 5G UE: nr-uesoftmodem
  • The LTE eNodeB: lte-softmodem
  • The 5G gNodeB: nr-softmodem
  • The 5G CU-UP: nr-cuup
  • The LTE PHY simulators: dlsim and ulsim
  • The 5G PHY simulators: nr_dlschsim, nr_dlsim, nr_pbchsim, nr_pucchsim, nr_ulschsim, nr_ulsim, polartest, smallblocktest, nr _ulsim, ldpctest, nr_srssim

Running the build_oai script also generates some utilities required to build and/or run the oai softmodem binaries:

  • conf2uedata: a binary used to build the (4G) UE data from a configuration file. The created file emulates the sim card of a 3GPP compliant phone.
  • nvram: a binary used to build (4G) UE (IMEI…) and EMM (IMSI, registered PLMN) non volatile data.
  • genids T Tracer utility, used at build time to generate T_IDs.h include file. This binary is located in the T Tracer source file directory .

The build system for OAI uses cmake which is a tool to generate makefiles. The build_oai script is a wrapper using cmake and make/ninja to ease the oai build and use. It logs the cmake and ninja/make commands it executes. The file describing how to build the executables from source files is the CMakeLists.txt, it is used as input by cmake to generate the makefiles.

cmake is further extended by using CPM. CPM is a cmake script that handles external code dependencies. It is setup to cache downloaded code in ~/.cache/cpm. While most external dependencies should be handled by system package managers, CPM has the advantage of using any code that is available in a public git repository.

The oai softmodem supports many use cases, and new ones are regularly added. Most of them are accessible using the configuration file or the command line options and continuous effort is done to avoid introducing build options as it makes tests and usage more complicated than run-time options. The following functionalities, originally requiring a specific build are now accessible by configuration or command line options:

  • s1, noS1
  • all simulators as the rfsimulator, the L2 simulator, with exception of PHY simulators, which are distinct executables.

Running build_oai

List of options

Calling the build_oai script with the -h option gives the list of all available options. A number of important ones:

  • The -I option is to install pre-requisites, you only need it the first time you build the softmodem or when some oai dependencies have changed.
  • The -w option is to select the radio head support you want to include in your build. Radio head support is provided via a shared library, which is called the “oai device” The build script creates a soft link from liboai_device.so to the true device which will be used at run-time (here the USRP one, liboai_usrpdevif.so). The RF simulatorRF simulator is implemented as a specific device replacing RF hardware, it can be specifically built using -w SIMU option, but is also built during any softmodem build.
  • --eNB is to build the lte-softmodem executable and all required shared libraries
  • --gNB is to build the nr-softmodem and nr-cuup executables and all required shared libraries
  • --UE is to build the lte-uesoftmodem executable and all required shared libraries
  • --nrUE is to build the nr-uesoftmodem executable and all required shared libraries
  • --ninja is to use the ninja build tool, which speeds up compilation.
  • -c is to clean the workspace and force a complete rebuild.

build_oai also provides various options to enable runtime error checkers, i.e. sanitizers in order to find various types of bugs in the codebase and eventually enhance the stability of the OAI softmodems. Refer to sanitizers.md for more details.

Installing dependencies

Install all dependencies by issuing the -I option. To install furthermore libraries for optional libraries, use the --install-optional-packages option. The -I option will also install dependencies for an SDR when paired with -w. For instance, in order to install all dependencies and the ones for USRP, run:

cd openairinterface5g/cmake_targets/
./build_oai -I --install-optional-packages -w USRP

Note the section on installing UHD further down for more information.

Installing (new) asn1c from source

With tag 2023.w22, we switch from our own asn1c to a community-maintained asn1c. This new version has many bugfixes, but is incompatible with the previous version. To ease the transition, both versions can be installed in parallel. Assuming you installed asn1c using build_oai, tags before 2023.w22 will use the version under /usr/local/; tag 2023.w22 and newer will use the version under /opt/asn1c/ (if present) or any system directory (e.g., also /usr/local/), and additionally check that all command line options of the new asn1c are supported.

To install the new asn1c, either run build_oai -I. To not re-install all packages, you can also just install asn1c like this: 

cd openairinterface5g
sudo ls                               # open sudo session, required by install_asn1c_from_source
. oaienv                              # read of default variables
. cmake_targets/tools/build_helper    # read in function
install_asn1c_from_source             # install under `/opt/asn1c`

Additionally, you can also point to a specific asn1c to use if you chose to install elsewhere, using one of these two methods: 

./build_oai --ninja <other-options> --cmake-opt -DASN1C_EXEC=/opt/asn1c/bin/asn1c
cmake .. -GNinja -DASN1C_EXEC=/opt/asn1c/bin/asn1c

Installing UHD from source

Previously for Ubuntu distributions, when installing the pre-requisites, most of the packages are installed from PPA.

Especially the UHD driver, but you could not easily manage the version of libuhd that will be installed.

Now, when installing the pre-requisites, especially the UHD driver, you can now specify if you want to install from source or not.

  • For fedora-based OS, it was already the case all the time. But now you can specify which version to install.
  • For ubuntu OS, you can still install from the Ettus PPA or select a version to install from source.
  • In case of PPA installation, you do nothing special, the script will install the latest version available on the PPA.
    • ./build_oai -I -w USRP
  • In case of a installation from source, you do as followed:
export BUILD_UHD_FROM_SOURCE=True
export UHD_VERSION=3.15.0.0
./build_oai -I -w USRP

The UHD_VERSION env variable SHALL be a valid tag (minus v) from the https://github.com/EttusResearch/uhd.git repository.

CAUTION: Note that if you are using the OAI eNB in TDD mode with B2xx boards, a patch is mandatory.

Starting this commit, the patch is applied automatically in our automated builds.

See:

  • cmake_targets/tools/uhd-3.15-tdd-patch.diff
  • cmake_targets/tools/uhd-4.x-tdd-patch.diff
  • cmake_targets/tools/build_helper –> function install_usrp_uhd_driver_from_source

Building PHY Simulators

The PHY layer simulators (LTE and NR) can be built as follows:

cd openairinterface5g/cmake_targets/
./build_oai --phy_simulators

After completing the build, the binaries are available in the cmake_targets/ran_build/build directory.

Detailed information about these simulators can be found in the dedicated page

Building UEs, eNodeB and gNodeB Executables

After downloading the source files, a single build command can be used to get the binaries supporting all the oai softmodem use cases (UE and [eg]NodeB):

cd openairinterface5g/cmake_targets/
./build_oai -w USRP --eNB --UE --nrUE --gNB

You can build any oai softmodem executable separately, you may not need all of them depending on your oai usage.

After completing the build, the binaries are available in the cmake_targets/ran_build/build directory.

Building Optional Binaries

There are a number of optional libraries that can be built in support of the RAN, such as telnetsrv, scopes, offloading libraries, etc.

Using the help option of the build script you can get the list of available optional libraries.

./build_oai --build-lib all # build all
./build_oai --build-lib telnetsrv  # build only telnetsrv
./build_oai --build-lib "telnetsrv enbscope uescope nrscope"

The following libraries are build in CI and should always work: telnetsrv, enbscope, uescope, nrscope.

Some libraries have further dependencies and might not build on every system: - enbscope, uescope, nrscope: libforms/X - ldpc_cuda: CUDA - websrv: npm and others - ldpc_aal: DPDK with patch

Running cmake directly

build_oai is a wrapper on top of cmake. It is therefore possible to run cmake directly. An example using ninja: to build all “main targets” for 5G, excluding additional libraries: 

cd openairinterface5g
mkdir build && cd build
cmake .. -GNinja && ninja nr-softmodem nr-uesoftmodem nr-cuup params_libconfig coding rfsimulator ldpc

To build additional libraries, e.g., telnetsrv, do the following: 

cmake .. -GNinja -DENABLE_TELNETSRV=ON && ninja telnetsrv

A list of all libraries can be seen using ccmake .. or cmake-gui ...

It is currently not possible to build all targets in the form of cmake .. -GNinja && ninja: currently, SDRs are always exposed, even if you don’t have the dependencies, and some targets are simply broken. Again, build_oai list all targets that it builds, and you can use them with ninja

The default target directory of build_oai is the following, for historical reasons: 

cd openairinterface5g/cmake_targets/ran_build/build
cmake ../../.. -GNinja
ccmake ../../..
cmake-gui ../../..
You can of course use all standard cmake/ninja/make commands in this directory.

cmake presets

CMake presets are common project configure options. See https://cmake.org/cmake/help/latest/manual/cmake-presets.7.html

Configure presets:

  • default: Configure compilation with default options
  • tests: Same as above but ENABLE_TESTS and SANITIZE_ADDRESS is ON

Build presets:

  • 5gdefault: Build the software for NR rfsimulator test
  • default: same as 5gdefault
  • 4gdefault: Build the software for LTE rfsimulator test
  • tests: build all unit tests

To configure using configuration preset:

cmake --preset <preset_name>

To build using a build preset:

cmake --build --preset <preset_name>

Cross Compile

If you want to use cross-compiler on x86 platform for aarch64 version, please refer the cross-compile.md for more information.