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OpenAirInterface

For our testing we used the 2.1 release of the project.

How to Build

Build with Flexric

In this setup we have used OpenAirInterface built with the --build-e2 flag.

0. Required dependencies

0.1 Building Swig

$ git clone https://github.com/swig/swig.git && cd swig
$ git checkout release-4.2
$ ./autogen.sh
$ ./configure --prefix=/usr/
$ make -j$(nproc)
$ sudo make install

0.2 Installing other dependencies

$ sudo apt install libsctp-dev python3 cmake-curses-gui libpcre2-dev

1. Building OpenAirInterface

$ git clone https://gitlab.eurecom.fr/oai/openairinterface5g oai
$ cd oai
$ git checkout v2.1.0
$ ./build_oai -w USRP --gNB --nrUE --build-e2

2. Building Flexric

$ cd oai/openair2/E2AP/flexric
$ mkdir build && cd build
$ cmake -DSWIG_DIR=/usr/share/swig/4.2.0/ -DSWIG_EXECUTABLE=/usr/bin/swig -DCMAKE_C_COMPILER=gcc-10 -DCMAKE_CXX_COMPILER=g++-10 ..
$ make -j$(nproc)
$ sudo make install

3. Launching gNB

3.1 gNB configuration

First some modifications on the configuration file are required to make the gNB work properly. Some of the configurations bellow are optional depending on your setup.

$ cd /path-to/openairinterface5g/targets/PROJECTS/GENERIC-NR-5GC/CONF
$ vi gnb.sa.band78.fr1.106PRB.usrpb210.conf #in this case we're using the usrp b210.

tracking_area_code  =  1;
plmn_list = ({ mcc = 001; mnc = 01; mnc_length = 2; snssaiList = ({ sst = 1; }) }); #in this case we are using the test plmn 00101
...
min_rxtxtime = 6;
...
amf_ip_address      = ( { ipv4       = "191.4.205.169"; #change this to our amf ip; default for oai cn: 192.168.70.132
                          ipv6       = "192:168:30::17";
                          active     = "yes";
                          preference = "ipv4";
                        }
                      );


NETWORK_INTERFACES :
    {
        GNB_INTERFACE_NAME_FOR_NG_AMF            = "br01"; #change to our host machine network interface of choice
        GNB_IPV4_ADDRESS_FOR_NG_AMF              = "191.4.204.211"; #change to the ip addr of the interface selected 
        GNB_INTERFACE_NAME_FOR_NGU               = "br01"; #change to our host machine network interface of choice
        GNB_IPV4_ADDRESS_FOR_NGU                 = "191.4.204.211"; #change to the ip addr of the interface selected 
        GNB_PORT_FOR_S1U                         = 2152;
    };
...

e2_agent = {
    near_ric_ip_addr = "191.4.204.161" #change to to the ip addr of the ric. If you are running flexric locally --> 127.0.0.1
    sm_dir = "/usr/local/lib/flexric/"
};

3.2 Running nr-softmodem

$ sudo ./nr-softmodem -O /path-to/gnb.conf --sa -E --continuous-tx | tee oai.logs

4.0 F1 / 2 Split

First step is to configure both the centralized unit and the distributed unit. The modified configuration that we used can be found here

4.1 Configuration changes for the CU

...
local_s_if_name = "enp3s0"; #set this to your network interface
local_s_address = "191.4.205.149"; #use 127.0.0.4 with lo interface if trying to run both units in the same computer.
remote_s_address = "191.4.204.52"; #if you are trying to run more than one DU set this to 0.0.0.0 (any).
...
amf_ip_address = ( {
    ipv4 = "192.168.70.132";
    ipv6 = "192:168:30::17";
    active = "yes";
    preference = "ipv4";
});

 NETWORK_INTERFACES :
    {
        GNB_INTERFACE_NAME_FOR_NG_AMF            = "enp3s0";
        GNB_IPV4_ADDRESS_FOR_NG_AMF              = "191.4.205.149/23";
        GNB_INTERFACE_NAME_FOR_NGU               = "enp3s0";
        GNB_IPV4_ADDRESS_FOR_NGU                 = "191.4.205.149/23";
        GNB_PORT_FOR_S1U                         = 2152; # Spec 2152
    };
  }

4.2 Configuration changes for the DU

...
gNB_ID = 0xe00; #should be the same as the one defined on CU config.
gNB_DU_ID = 0xe00; #change this if running more than one DU.
...
//////// Physical parameters:
min_rxtxtime = 6;
...
local_n_if_name = "enp3s0"; #change this to your interface of choice.
local_n_address = "191.4.204.149"; #if running more than one DU change this to something different from the other DUs. 
remote_n_address = "191.4.204.174"; #change this to your CU ip addr, if local 127.0.0.4.

4.3 Launching both CU and DU

$ sudo ./nr-softmodem -O ~/cu.conf --sa -E --continuous-tx
$ sudo ./nr-softmodem -O ~/du.conf --sa -E --continuous-tx