OpenAirInterface LTE Tutorials

Prerequisites

This tutorial series assumes you have an ​ORBIT account, have ​scheduled a session on the ORBIT testbed, are familiar with ​SSH'ing into the testbed itself, and are familiar with the ​basics of running ORBIT experiments. If you have not done these things yet, you may wish to do so before taking a look at this slightly more advanced experiment. If you are unfamiliar with or are entirely new to ORBIT, you may wish to start ​here.

This set of tutorials also assumes basic familiarity with ​LTE standard. They are using ​OpenAirInterface open source software implementation of LTE basestation (eNodeB or eNB) and modem (user equipment or UE) developed at ​Eurecom.

The images used for these experiment are based on Ubunutu 14.04 and have low-latency 3.19 kernel (that was created based on ​OpenAir instructions) from ubutbu-14-04-64bit.ndz (baseline.ndz). In addition to installation steps in OpenAir documentation, once low latency kernel was installed, drivers for Broadcom and Netgear devices had to be manually re-installed.

Two images were created based on ​git cloning instructions and ​compiling instructions:

• oai-master.ndz - master branch clone from git in /root
• oai-develop.ndz - develop branch clone from git in /root

The openair-cn (EPC) was installed with default passwords of oai and default choice of "N" for optional packages (freeDiameter, asn1c pach and xtables_addons_oai). xtables_addons_oai was pulled out of git but not installed.

Update for oai-develop.ndz: The openair-cn (EPC) was installed with default passwords of oai and default choice of "Y" for optional packages (freeDiameter, asn1c pach and xtables_addons_oai). xtables_addons_oai was pulled out of git and installed.

Build and Execution Scripts

In the image oai-rrh.ndz, scripts are available to compile and execute components. They are divided into three categories

• Build: pulls from master, then compiles component
• Quickbuild: compiles component without pull
• Run: Runs component
• Available components are split eNB, Remote Radio Head(RRH), and combined eNB
• Sample config files are available in the ~/conf directory

Each of the build scripts is a simple wrapper around the OAI autobuild script, specifying common options. The run scripts execute the compiled component with common options.

Configuration Files

The run scripts reference the config files in ~/conf. These config files MUST be updated with the latest versions after any operation involving a git pull, as the configuration syntax is not stable across git versions.

Our COTS devices support only bands 25 and 41, and so the new configuration files must be modified to these frequencies. For band25, the band7 file is used as a template. For band41, the band38 file is used as a template. This is functional, but not entirely correct, as calibration must still be done for the new frequencies.

OAI Tutorials

The following basic tutorials based of the OAI source code are available. Note, a git pull was run before saving the images used in the below tutorials. To execute them, run the supplied scripts without pulling changes from openairinterface, as the necessary instructions or config files may change.:

• Basis OAI Tutorial
• OAI Remote Radio Head (RRH)
• OAI RRH in ORBIT with eNB Baseband in GENI