How to Connect OAI UE (USRP B210) with CMW

This tutorial is intended to explain how to attach OAI UE to CMW. Note that OAI1B-UE was tested only on FDD mode. Both CMW and OAI-UE should use the same clock (ref clock).

The procedures includes the following:

Build the UE in Ubuntu machine.
Run the UE.

1. Installing, Building and Running the OAI UE

Checklist prior to OAI installation:

Ubuntu 14.04 LTS (64-bit)
Kernel setup
- Disable C-states from BIOS (or from GRUB)
- Disable CPU freq. scaling
- Install low-latency kernel
Install git with the command:
- sudo apt-get install git for GIT version.
Run Autobuild for installing missing packages: the instructions are at AutoBuild

1.1 Installation UE on 1st Ubuntu Machine

Step 1: Check out the GIT trunk version of OAI1B

Note: OAI-UE development is done on OAI1B repository. First merge to OAI repository will be done soon.
Download the source codes using gitlab :

mkdir -p ~/openairinterface5g
git clone https://gitlab.eurecom.fr/oai1B/openairinterface5g.git
cd openairinterface5g
source oaienv

Step 2: Run Automated Build Script for UE

First, you need to modify the following files (see also git diff on the figure bellow):

set the PLMN (R&S)
- openair3/NAS/TOOLS/network.h
- modify the line #define SELECTED_PLMN TEST1 //OAI_LTEBOX
configure usrp with external clock
- target/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp
- in function device_init: comment the line s->usrp->set_clock_source("internal"); set s->usrp->set_clock_source("external");

connect via cable REF OUT (CMW) -> REF IN (USRP) (see figure bellow)

Build the UE in S1 mode supporting B210:

cd ~/openairinterface5g/
source oaienv
cd cmake_targets
./build_oai -w USRP --eNB --UE -x

This should starts the building process in ~/openairinterface5g/cmake_targets/lte_build_oai.

2. Running CMW and OAI UE

CMW should be started first before running the OAI UE. Both CMW and OAI UE are running on LTE FDD Band 7 (DL: 2655MHz, UL: 2535MHz).

2.1 Run UE on 2nd Ubuntu Machine

Step 1: Running the CMW

In case of callbox, you need to set up the cell in the appropriate configuration (band, mode, bandwidth etc) and make sure that the cell is running. In case of protocol tester, you need to: 1- configure the pics file with the appropriate configuration (band, mode, bandwidth etc [see attached file that we use on our setup]) 2- make sure that selected scenario is compatible UE capabilities (SISO) 3- run the test scenario

Step 2: Running the UE

Cell bandwidth: 5MHz Band 7 EARFCN: 3100 The command of running the UE should be as follow:

cd cmake_targets
sudo ./lte_build_oai/build/lte-softmodem -U -C2655000000 --ue-scan-carrier  -r25 --ue-txgain 90 --ue-rxgain 110 -d --usim-test | tee UE.log

-r25: 25 RBs i.e 5MHz bandwidth

--ue-txgain : should be determined via calibration (on our setup we set it to 90)

--ue-rxgain : should be determined via calibration (on our setup we set it to 110)

--usim-test : this is execution flag that configures the UE on USIM test mode (mandatory for R&S tests)

By running UE with pipes tee UE.log, allow you to record the UE logging to be used for further investigation.