4G: OpenAirInterface dari OpenCell

Sumber: https://open-cells.com/index.php/2019/09/22/all-in-one-openairinterface/

Yang digunakan

• Ubuntu 18.04 64bit
• Ettus B210 (kalau ada), kalau tidak ada kita coba simulasi physical.

Download Source OAI EPC

sudo apt install git
git config --global user.name "Onno"
git config --global user.email "onno@indo.net.id"

Sebagai user biasa, download config mods dari opencells

cd ~
wget https://open-cells.com/opencells-mods-20190923.tgz
tar xf opencells-mods-20190923.tgz

Download and patch EPC

cd ~
wget https://open-cells.com/d5138782a8739209ec5760865b1e53b0/openair-cn.tgz
tar xf openair-cn.tgz
cd openair-cn
git checkout develop

Apply the patch:

git apply ~/opencells-mods/EPC.patch

What is in the patch file:

• Add Ubuntu 18.04 for compilation and fix some bugs
• Remove link between Linux host name and LTE diameter protocol configuration
• Add usage of the input address for the SGW input socket

modify the freediameter S6a interface to fix a wrong OAI parameter

• No kernel module patch is required: generic Ubuntu kernel 18.04 works fine with OAI
• separate ASN.1 compiler installation to be compatible with other OpenAir components on the same machine (ans1c version is different for eNB and gNB)

Install third party SW for EPC

cd ~/openair-cn
source oaienv
cd scripts
./build_hss -i

Answer yes to install: freeDiameter 1.2.0

For ubuntu 18.04, we set back the legacy mysql security level

sudo mysql -u root << END
USE mysql;
UPDATE user SET plugin='mysql_native_password' WHERE User='root';
FLUSH PRIVILEGES;
END

sudo systemctl restart mysql.service

Install 3PP SW for mme and spgw

./build_mme -i
Do you want to install freeDiameter 1.2.0: no
Do you want to install asn1c rev 1516 patched? <y/N>: yes
Do you want to install libgtpnl ? <y/N>: yes
wireshark permissions: as you prefer
./build_spgw -i
Do you want to install libgtpnl ? <y/N>: no

Compile the EPC nodes No difficulty found in this phase.

cd openair-cn; source oaienv; cd scripts
./build_hss
./build_mme
./build_spgw

If you face compilation issues, the log files are in

openair-cn/build/log

In there files, look for “error:” string.

Download & Compile the eNB on 18.04

git clone https://gitlab.eurecom.fr/oai/openairinterface5g.git
cd openairinterface5g
git checkout develop

We tested with commit edb74831dabf79686eb5a92fbf8fc06e6b267d35 Build in two steps

source oaienv  
./cmake_targets/build_oai -I  # install SW packages from internet
./cmake_targets/build_oai -w USRP --eNB --UE # compile eNB and UE

Our Network setup description I’ve made a simple configuration for this all-in-one setup.

Each node is on a separate IP address, this address is used for all it’s interfaces. In our case of all-in-one, we take addresses on the loopback: this will be fine on all your machines.

HSS is on localhost: 127.0.0.1 eNB is on 127.0.0.10 MME is on 127.0.0.20 SPGW is on 127.0.0.30 The LTE diameter configuration is now isolated from Linux hostname.

realm for our EPC: “OpenAir5G.Alliance”, so, full distinguish names (FQDN) are: hss.OpenAir5G.Alliance, mme.OpenAir5G.Alliance

Install this configuration for eNB In your eNB configuration file, the network is now fixed, as lo interface always exists and our computer internal addresses also:

////////// MME parameters:
 mme_ip_address = ( { ipv4 = "127.0.0.20";
 ipv6 = "192:168:30::17";
 active = "yes";
 preference = "ipv4";
 }
 );

NETWORK_INTERFACES : 
 {
 ENB_INTERFACE_NAME_FOR_S1_MME = "lo";
 ENB_IPV4_ADDRESS_FOR_S1_MME = "127.0.0.10/8"; 

 ENB_INTERFACE_NAME_FOR_S1U = "lo";
 ENB_IPV4_ADDRESS_FOR_S1U = "127.0.0.10/8";
 ENB_PORT_FOR_S1U = 2152; # Spec 2152
 };

In the eNB config file, you need also to set the MCC and MNC as per your SIM card:

tracking_area_code = “1”;
mobile_country_code = “208”;
mobile_network_code = “92”;

And obviously, your radio parameters.

Wwe tested with USRP B210 20MHz band, Huawei E3272 UE, a cavity duplexer a simple antenna, about 1 meter distance UE/eNB antenna with this file:

~/opencells-mods/enb.10MHz.b200

if you use the OpenAir UE, a sim card file that match our hss database example: opencells-mods/sim.conf. We will make another tutorial to use together OpenAir UE and rf board simulation

Install this configuration for EPC For the EPC, we install in OAI default directory: /usr/local/etc/oai

sudo mkdir -p /usr/local/etc/oai
sudo cp -rp ~/opencells-mods/config_epc/* /usr/local/etc/oai
cd openair-cn; source oaienv; cd scripts
./check_hss_s6a_certificate /usr/local/etc/oai/freeDiameter hss.OpenAir5G.Alliance
./check_mme_s6a_certificate /usr/local/etc/oai/freeDiameter mme.OpenAir5G.Alliance

Only the SGi output to internet need to be configured.

In /usr/local/etc/oai/spgw.conf, your should set the Ethernet interface that is connected to Internet, and, to tell to the PGW to implement NAPT for the UE traffic

PGW_INTERFACE_NAME_FOR_SGI = "enp3s0"; 
PGW_MASQUERADE_SGI = "yes";

For the SIM card, you’ll have more to do:

• SIM MCC/MNC should be duplicated in a couple of files
• eNB: See above in eNB configuration chapter
• MME file: /usr/local/etc/oai/mme.conf to update

GUMMEI_LIST = ( MCC="208" ; MNC="92"; MME_GID="4" ; MME_CODE="1"; } );
TAI_LIST = ({MCC="208" ; MNC="92"; TAC = "1"; } );
HSS

Configure the password for MySQL in /usr/local/etc/oai/hss.conf, set password as the password you created during MySQL installation A HSS database in text is in: ~/opencells-mods/opencells_db.sql We don’t use phpmyadmin: we load the database from a ascii file It is pre-configured with the

mme id

10 users is network 208/92 (a French test network) are also created (don’t use 3GPP test network: 001/01: the mme fails when MCC starts by “0”)

Each time you import this db, it erases the entire database (example: you set mysql password to “linux”) ~/opencells-mods/hss_import 127.0.0.1 root linux oai_db ~/opencells-mods/opencells_db.sql We use to modify the db by updating this file with regular text editor, then we re-load the entire database, but, if you prefer, usage of http://localhost/phpmyadmin is fine. if you modified the hss db directly, we offer a export script:

~/opencells-mods/hss_export

The important values to set are:

• table pdn:

all IMSI are listed, with the APN: these values are in UE/USIM

• table users:

all IMSI, key (Ki) and OPc must be the same in USIM card Sqn increments automatically when the UE authenticate in both USIM and HSS DB: it should be set as per USIM internal incrementation

SIM card update Open cells UICC and card reader will be supported Final test and verification open 4 terminal windows

in each window

cd openair-cn; source oaienv; cd scripts; ./run_hss
cd openair-cn; source oaienv; cd scripts; ./run_mme
cd openair-cn; source oaienv; cd scripts; sudo -E ./run_spgw
sudo bash
cd ~/openairinterface5g; source oaienv
cd cmake_targets/lte_build_oai/build

./lte-softmodem -O ~/opencells-mods/enb.10MHz.b200

Connect the UE, it should attach to network and be able to reach internet through OAI network.

If the UE attaches, but you don’t have internet access, verify phone configuration: enable data in config->sim and verify the APN value

Issues related to CPU power If you reach performance issues: USRP/UHD prints “LLLLL” or the process exits “problem with samples”, OVERFLOW, …

The first case is to verify the USRP dialogs over USB3 (not USB2): the process must report:

Found USRP B200
-- Detected Device: B200
-- Operating over USB 3.

For OAI source code, we wrote improvements and some hints for UE performance last year. The Linux/Ubuntu advises can be applied to the eNB:

https://gitlab.eurecom.fr/oai/openairinterface5g/wikis/setup-for-real-time-performance

We may make later a post for eNB (OAI/eNB can reach much better performance than today develop branch, but it require to enhance parts of the source code).

We re-built this procedure from scratch and tested i5-6600K.

On the i5-6600K, we obtained stable performance at maximum traffic over 20MHz, transmission mode 1 (SISO), duplexer, antenna, E3372 UE (one single UE) over-the-air 10 cm distance :

Referensi

• https://open-cells.com/index.php/2019/09/22/all-in-one-openairinterface/