RF simulator and OAI UE tutorial

Version 0: initial writing

This tutorial explains how to run OpenAir EPC+eNB+UE with a RF card simulator.

Starting point: the all-in-one tutorial has been run, so the system is installed and running.

Setup the UE

The all-in-one tutorial already compiled the UE, even if we didn’t use it yet.

Our patch file also contains the needed configuration files.

We need now to add a virtual SIM card in binary form to our directory:

../../nas_sim_tools/build/conf2uedata -c ~/opencells-mods/sim.conf -o .

conf2uedata command compiles a OpenAir ascii description of a SIM card into binary files that the OpenAir UE can read.

The hss dump file we provided contains the same SIM card.

Two machines: UE on a second machine

Assuming here you have a separate machine for the UE, you have to install OAI again, nevertheless the next step is easy.

On eNB machine, run the eNB as with RF board, but adding “–rfsim” and some parameters in the configuration file (see “rfsimulator” section we added in ~/opencells-mods/enb.10MHz.b200).

sudo ./lte-softmodem –rfsim -O ~/opencells-mods/enb.10MHz.b200 –log_config.hw_log_level error

“–log_config.hw_log_level error” is there to show how you can change the log level per component on the command line. This is possible for all parameters. We will use the same for UE, because the UE doesn’t have a configuration file.

Lets’ run the UE on the second machine

./lte-uesoftmodem -C 2685000000 -r 50 --rfsim --rfsimulator.serveraddr a.b.c.d

a.b.s.d is the eNB machine IP address.

The UE is now running, any IP traffic can be routed by the LTE network: UE+eNB+EPC

One machine UE + SGi interface

3GPP networks tunnel the UE IP address to the SGi.

SGi is in the PGW for regular LTE, maybe in the eNB in OpenAir noS1 mode.

The UE can’t run directly on the same “machine” because both UE and the 3GPP network border (PGW, or eNB in all cases where eNB performs local connection to internet (OAI nS1, LIPA, SIPTO, …)) will try to route the same IP address.

One solution is to run the UE in a virtual machine.

A lighter solution is to create only a network namespace for the UE (a component of a “virtual machine”)

In case of previous trails, delete the already created network namespaces

assuming enp0s31f6 is your network interface to internet, and that network 10.200.1.0 can be used freely in your intranet.

ip netns delete ueNameSpace
ip link delete v-eth1
ip netns add ueNameSpace  
ip link add v-eth1 type veth peer name v-ue1
ip link set v-ue1 netns ueNameSpace
ip addr add 10.200.1.1/24 dev v-eth1  
ip link set v-eth1 up  
iptables -t nat -A POSTROUTING -s 10.200.1.0/255.255.255.0 -o enp0s31f6 -j MASQUERADE  
iptables -A FORWARD -i enp0s31f6 -o v-eth1 -j ACCEPT  
iptables -A FORWARD -o enp0s31f6 -i v-eth1 -j ACCEPT 
ip netns exec ueNameSpace ip link set dev lo up   
ip netns exec ueNameSpace ip addr add 10.200.1.2/24 dev v-ue1  
ip netns exec ueNameSpace ip link set v-ue1 up 

Set your window in the new namespace:

ip netns exec ueNameSpace bash

Run the UE

./lte-uesoftmodem -C 2685000000 -r 50 --rfsim --rfsimulator.serveraddr 10.200.1.1

you need now to transfer all ip packets in the namespace to the IP interface created by the OpenAir UE

route add default oaitun_ue1

Now, you can run any application in the UE namespace: all IP traffic will go through the UE+eNB+EPC

ip netns exec ueNameSpace bash
ping 8.8.8.8

DNS in the UE namespace

DNS resolv is convenient to use in the UE namespace.

If your DNS configuration uses a gateway on lo (a address starting by 127.0.0 as do Ubuntu by default), resolv won’t work because you have another lo interface inside the network namespace (so the DNS query won’t reach the resolver outside of the namespace).

The simplest is to add a routable DNS server in your Linux configuration for also this namespace, example using the google DNS server:

sudo echo 'nameserver 8.8.8.8' >> /etc/resolv.conf

All in one OpenAirInterface

September 23rd 2019: minor fix of warnings

(september 2019, large rework and update to latest eNB)

(june 21st 2019: replace ubuntu 17.04 by ubuntu 18.04)

(Sept 7th 2017: small update for more recent eNB git commit version in develop branch)

Starting condition:
Ubuntu 18.04 all packages upgraded, uhd last commit, OAI last commit

Modifications

  • Latest commits
  • Fix a issue in mme that crash mme with some phones in the attach-request procedure
    If you want to fix only this issue, pick files:
    src/nas/emm/Attach.c
    src/nas/ies/SupportedCodecList.c
    in the hereafter tar file
    The issue is: mme wrong decoding of smartphone codec list
  • Full re-test, from disk install of Ubuntu 17.04 to commercial UEs throughput measurement (Android 5 and Android 6)

This document explains how to install and configure OAI EPC+eNB on one single Ubuntu 18.04 64 bits machine connected with a regular UE, routing the UE traffic to internet.

The description uses a USRP B210 board.

We also explain how to simplify, fix existing issues, to make a single computer as a full LTE network: EPC+eNB.

Known limitations fixed in the hereafter description

  • GTP UDP ports are in conflict for eNB and SGW
  • Useless link between OAI and the Ubuntu/Linux hostname removed
  • Several simplifications and precisions to make easier and reliable installations

Install Ubuntu

  • Prepare a machine: a 4 actual cores, no hyper-threading.
    All other configuration in OAI Wiki (C1 states, …) describes is about useless.
  • Download Ubuntu 18.04 64 bits version iso file
  • create a usb key to boot on it
  • install Ubuntu: choose to install Third party SW, and to upgrade all packages while installing
  • do: apt update; apt upgrade until the machine is up-to-date
  • install git and configure your identification in git:
     sudo apt install git 
     git config --global user.name "Laurent"
     git config --global user.email "laurent.thomas@open-cells.com"
  • Add the OAI repository as authorized remote system
    echo -n | openssl s_client -showcerts -connect gitlab.eurecom.fr:443 2>/dev/null | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' | sudo tee -a /etc/ssl/certs/ca-certificates.crt
  • if you are upset with sudo password, add this line in /etc/sudoers
    • xxxxxx ALL=(ALL) NOPASSWD: ALL (xxxxxx is your login name)
    • sudo will not ask anymore for a password

Install USRP drivers

We prefer to use UHD driver from source:

sudo apt-get install libboost-all-dev libusb-1.0-0-dev python-mako doxygen python-docutils python-requests python3-pip cmake build-essential
pip3 install mako numpy
git clone git://github.com/EttusResearch/uhd.git
cd uhd; mkdir host/build; cd host/build
cmake -DCMAKE_INSTALL_PREFIX=/usr ..
make -j4
sudo make install
sudo ldconfig
sudo /usr/lib/uhd/utils/uhd_images_downloader.py

Download our modifications

download: patches   extract the data:

cd
tar xf Downloads/opencells-mods-20190923.tgz

Download and patch EPC

Clone OAI EPC:

# maybe go back to home directory (leave openairinterface5g directory)
git clone https://gitlab.eurecom.fr/oai/openair-cn.git
cd openair-cn
git checkout develop

We tested with commit: 724542d0b59797b010af8c5df15af7f669c1e838

The Eurecom gitlab require now a login, if you don’t have one, a copy of the git repository is in:openair-cn extract the tar with

tar xf openair-cn.tgz
cd openair-cn
git checkout develop

This is the last commit for OAI EPC on this development tree. Active OpenAir EPC is now another project on github. We use here this legacy EPC because the installation is quite easy (the new project uses Cassandra, al LOT of virtual machines, OpenVswitch and complex dependancies).

Apply the patch:

git apply ~/opencells-mods/EPC.patch

The new version of the source files are also in the tar, if you want to merge with another version of OpenAir EPC

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
  • phpmyadmin:
    • We don’t use phpmyadmin later in this procedure to update the MySQL database
    • We removed the installation of phpmyadmin (of course you can use it if you prefer)

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

sudo mysql_secure_installation

The last command will ask a few questions:

    • password: set your password (linux is set in our default config files)
    • VALIDATE PASSWORD PLUGIN: no
    • Remove anonymous users: yes
    • Disallow root login remotely: yes
    • Remove test database and access to it: yes
    • Reload privilege tables now: yes
  • 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

  1. 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 :

dielectric duplexers

Dielectric duplexers

We consider to make dielectric duplexers.

We would like some feedback on this post from interested future customers (no commitment).

The early prototype is like this with SMA connectors

This is much cheaper and smaller than cavity duplexers.

The technical specifications are also a bit lower: insertion loss is about 2dB, rejection between channels is around 50dB, maximum power near 2 watts

Target price would be 50€/piece,
shipping will also be low cost as the device is small.

We consider these 3 bands

Band3:1710-1785/1805-1880MHz
Band7:2500-2570/2620-2690MHz
Band13:777-787/746-756MHz

Connectors can be SMA or U.FL (we will supply also the cables if needed).

We actually need some feedback to decide to produce these devices

If you need some other devices on top of USRP, Lime, … you can also feedback in this post.

LimeSDR new set of tests

We use the latest commit in https://github.com/myriadrf/LimeSuite.git

Ubuntu 18.04

LimeSDR (HW: V1.4) flashed with latest firmware (Limeutil –update)

Scope: LTE SISO downlink signal

We use a custom OpenAirInterface version

The LimeSDR interface code is:

LMS_Open(&lms_device,list[0],NULL);
 LMS_Init(lms_device);
 LMS_Reset(lms_device);

LMS_EnableCalibCache(lms_device,false);
 LMS_LoadConfig(lms_device, );
 LMS_SetSampleRate(lms_device,4), “”); //rate is LTE standard one, so a division of 30720MS/s
 LMS_SetLOFrequency(lms_device,LMS_CH_RX, 0); // several feq tested 700MHz-3600MHz
 LMS_SetLOFrequency(lms_device,LMS_CH_TX, 0); // Tx/Rx freq are different, gap is defined by 3GPP
 LMS_SetGaindB(lms_device, LMS_CH_TX, 0, MyGain);
 LMS_SetGaindB(lms_device, LMS_CH_RX, 0, MyGain);
 //value is 0…70, we saw the today limitation: it is not actually in dB, but still the range is 0…70
 LMS_SetLPFBW(lms_device,LMS_CH_RX,0,ChosenLTEBand); // 5MHz or 10MHz or 20MHz
 LMS_SetLPFBW(lms_device,LMS_CH_TX,0,ChosenLTEBand);
 LMS_Calibrate(lms_device,LMS_CH_RX,0,ChosenLTEBand,0);
 LMS_Calibrate(lms_device,LMS_CH_TX,i,ChosenLTEBand,0)

First observation is: the API calls often fails: calibration reports failures

With some ini files, it is simply impossible to run successfully the above sequence.

With “good” ini files, we have to power-off the board before each trial.

The key problem is to make a decent .ini file, that is good only in a specific case: RF band, modulated band, power, …

Then, even with a good ini file, the result of the calibration is not repeatable, and often fails randomly (need to power off the LimeSDR board).

Measuring this DL signal

A USRP B210 output:

The best of LimeSDR can be close to this

Even in this best result, the DC offset is not well calibrated

Also it is not repeatable, and depend heavily of the .ini file we use

or non repeatable results

At lower frequency, LimeSDR is globally better

Support page

We released our software to program UICC/SIM/USIM cards.

We tested and support it only with our cards and our card reader, nevertheless it is GPL license open source.

Please provide us with enhancements source code, as per GPL license rules

uicc-software

We offer support as comments on this blog page, and a FAQ

(if your question is very confidential, send us a mail)

kernel module in UEFI secure boot

Signed kernel module: how to

  • Compilation of a kernel module like this example
    • cd opencells-mods/gtp_mod
    • make -C /lib/modules/$(uname -r)/build M=$PWD
    • sudo cp gtp.ko /lib/modules/$(uname -r)/kernel/drivers/net/gtp.ko
  • But, despite we just compiled it successfully,  the module can’t be loaded
    • modprobe gtp
    • ERROR: could not insert ‘gtp’: Operation not permitted

your kernel boot is in “secure boot”, the module can’t be loaded

This issue occurs also with other modules in AOI, like ue_ip.kp

  • Solution 1
      • Remove “secure boot” entirely
      • depends on UEFI bios
      • Can be done by
      • sudo apt install mokutil
        
        sudo mokutil --disable-validation
      • After this, reboot  the computer, the UEFI bios should ask for the password you set with “mokutil”, then ask to accept to disable secure boot
  • Solution 2
    • Sign your modules
    • add you own signature to valid signatures
      • create ciphering keys
      • openssl req -new -x509 -newkey rsa:2048 -keyout OCP.priv -outform DER -out OCP.der -nodes -days 36500 -subj "/CN=OpenCells/"
      • keep the two files OCP.der, OCP.priv as you’ll need it to sign your kernel modules
      • import it in UEFI boot
      • sudo mokutil --import OCP.der
      • It asks for a password: put any string, you’ll need it once, at next reboot, to secure the new ciphering enrolling
      • You need to reboot the machine to enroll this new key
    • Now you can sign your modules
      • each time you compile a module, you have to sign it
      • (after: sudo cp gtp.ko /lib/modules/`uname -r`/kernel/drivers/net/gtp.ko)
    • sudo /usr/src/linux-headers-$(uname -r)/scripts/sign-file sha256 ./OCP.priv ./OCP.der $(modinfo -n gtp)
    • now “sudo modprobe gtp”  should not complain anymore
  • You’ll need to compile and update the module after each Ubuntu kernel upgrades

(obsolete) OpenAir, single machine Ubuntu 17.04, after major EPC update

(updated: 2017, July 10th)

Modifs since version on July 6th:

  • Latest commit
  • Fix lacking file in the tarball
    (non modified ones since the June version were missing)
  • improved code pieces formating in HTML, added automatic git patch
  • Full re-test, from disk install of Ubuntu 17.04 to UE throughput measurement

This document explains how to install and configure OAI EPC+eNB on one single Ubuntu 17.04 64 bits machine connected with a regular UE (a Huawei E3272), routing the UE traffic to internet.

We use EPC after a major contribution in May 2017: a lot of code has been modified, all directories names were changes, configuration parameters names/values changed.

The description uses a USRP B210 board, a Lime SDR page is provided separately.

We also explain how to simplify, fix existing issues, to make a single computer as a full LTE network: EPC+eNB.

Known limitations fixed in the hereafter description

  • OAI EPC require kernel >= 4.7, so we have to use Ubuntu 17.04
    • We already pushed some enhancements in OAI, nevertheless some more are required
  • GTP UDP ports are in conflict for eNB and SGW
  • Useless link between OAI and the Ubuntu/Linux hostname removed
  • Several simplifications and precisions to make easier and reliable installations

Install Ubuntu

  • Prepare a machine: a 4 actual cores, no hyper-threading.
    All other configuration in OAI Wiki (C1 states, …) describes is about useless.
  • Download Ubuntu 17.04 64 bits version iso file
  • create a usb key to boot on it
  • install Ubuntu: choose to install Third party SW, and to upgrade all packages while installing
  • do: apt update; apt upgrade until the machine is up-to-date
  • install git and configure your identification in git:
     sudo apt install git 
     git config --global user.name "Laurent"
     git config --global user.email "laurent.thomas@open-cells.com"
  • Add the OAI repository as authorized remote system
    echo -n | openssl s_client -showcerts -connect gitlab.eurecom.fr:443 2>/dev/null | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' | sudo tee -a /etc/ssl/certs/ca-certificates.crt
  • if you are upset with sudo password, add this line in /etc/sudoers
    • xxxxxx ALL=(ALL) NOPASSWD: ALL (xxxxxx is your login name)
    • sudo will not ask anymore for a password

Install USRP drivers

Ettus has not yet released their driver for Ubuntu 17.04, we take it from source:

sudo apt-get install libboost-all-dev libusb-1.0-0-dev python-mako doxygen python-docutils python-requests cmake build-essential
git clone git://github.com/EttusResearch/uhd.git
cd uhd; mkdir host/build; cd host/build
cmake -DCMAKE_INSTALL_PREFIX=/usr ..
make -j4
sudo make install
sudo ldconfig
sudo /usr/lib/uhd/utils/uhd_images_downloader.py

Download our modifications

download: patches   extract the data:

tar xf opencells-mods-20170710.tgz

Download & Compile the eNB on 17.04

git clone https://gitlab.eurecom.fr/oai/openairinterface5g.git
cd openairinterface5g
git checkout develop
  • We tested with commit 08b8b3142df16831396a5283a015564ff56bf91c

We already merged in develop most of updates for Ubuntu 17.04, so we need only to add in build_helper file the Ubuntu 17.04 support

git apply opencells-mods/eNB.patch
  • Now, you should be able to build as usual the eNB
source oaienv  
./cmake_targets/build_oai -I       # install SW packages from internet
./cmake_targets/build_oai  -w USRP --eNB --UE # compile eNB

Download and patch EPC

Clone OAI EPC:

git clone https://gitlab.eurecom.fr/oai/openair-cn.git
cd openair-cn
git checkout develop

(we used: commit 5353b606662a6ae7eaadf6bc39cbf6452d298b0e)

Apply the patch:

git apply opencells-mods/EPC.patch

The new version of the source files are also in the tar, if you want to merge with another version of OpenAir EPC

What is in the patch file:

  • Add Ubuntu 17.04 for compilation and fix some bugs
    • build/tools/build_helper
    • src/common/common_defs.h
    • src/oai_hss/utils/hss_config.c
  • Remove link between Linux host name and LTE diameter protocol configuration
    • src/s6a/s6a_peer.c
  • Add usage of the input address for the SGW input socket
    • src/gtpv1-u/gtp_mod_kernel.c
    • src/gtpv1-u/gtp_mod_kernel.h
    • src/gtpv1-u/gtpv1u_task.c

No kernel module patch is required anymore: generic Ubuntu kernel 17.04 works fine with OAI

Install third party SW for EPC

cd openair-cn; source oaienv; cd scripts
./build_hss -i
  • Do you want to install freeDiameter 1.2.0 ?: yes
  • set your MySQL password and remember it!
  • Answer yes to install: freeDiameter 1.2.0
  • phpmyadmin:
    • choose light or apache as you prefer
    • Configure database for phpmyadmin with dbconfig-common: yes
    • password: same as MySQL for simplicity
    • We don’t use phpmyadmin later in this procedure, nevertheless we tested successfully also with it
  • 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>: no
  • 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

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 and two parameter files: 10MHz band, 20MHz band, Huawei E3272 UE, a cavity duplexer a simple antenna, about 1 meter distance UE/eNB antenna.

  • openairinterface5g/targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band7.tm1.50PRB.usrpb210.conf
  • openairinterface5g/targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band7.tm1.100PRB.usrpb210.conf

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”)
./hss_db_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
        • 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

  1. 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
./cmake_targets/lte_build_oai/build/lte-softmodem -O <your config file>

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

We re-built this procedure from scratch and tested two machines: i5-4570 and i5-6600K.

On the i5-4570, at maximum traffic, the eNB is stable on 10MHz band at full user data speed.

On the i5-6600K, we obtain stable performance at maximum traffic over 20MHz, transmission mode 1 (SISO), one single UE over-the-air 1 meter distance:

Intel CPUs performance

Most people recommends to disable hyper-threading for tasks such as signal processing on Intel CPUs.

So,there will be no difference between two CPUs, if they have same core architecture and same number of actual cores.

Not only frequency matter: instructions set (AVX2 for example) and the core internal architecture are important.

Many people have issues related to thermal capacity of the box: brick like format may decrease CPU performance if it becomes too hot.

Taking 3 different CPUs, similar SSD, Ubuntu, let’s see how OAI performs with OAI PHY unitary tests

General purpose usage: let’s compile the OAI PHY simulators

 N3160
Ubuntu 17.04
i5-4300M
Ubuntu 16.04
i5-6600K
Ubuntu 17.04
Total cpu cost cumulated all cores395 sec146 sec75 sec
Elapsed time216s sec80 sec40 sec

Now, we run OAI phy processing on one core

 N3160i5-4300Mi5-6600K
Detected cpu_freq1.6 GHz
(turbo: 2.2GHz)
2.6 GHz
(Turbo 3.3GHz)
3.5 GHz
(overclock: 4.1GHz)
UE mode: Total PHY proc tx339.031893 us72.814188 us50.013725 us
UE mode: only
ULSCH multiplexing time
20.204291 us7.258590 us5.122038 us
eNB mode: total time483.742061 us 86.693388 us62.064970 us

Conclusion:

N3160, that is recent Atom core architecture (Braswell) is much slower than main stream core architecture.

On main stream CPUs, Intel improved but not that much between Haswell architecture and Skylake.

The difference between the two i5-xxxx is also small because both have AVX2 instructions.

Intel developed more the GPU part between gen 4 (Haswell) and gen 6 (Skylake).

If we take a older CPU like ix-3xxx or before, the difference will be larger for same frequency.

If some people perform similar tests with i7-xxxx or Xeon, they will find out the same values for the same core architecture, no matter the commercial denomination.

LimeSDR installation

Tutorial to install LimeSDR USB instead of USRP in the setup described in:

OpenAir, single machine Ubuntu 17.04, after major EPC update

Considering LimeSDR is under development we will install all from source

Add Ubuntu packages required by SoapySDR and LimSDR

sudo apt-get install cmake g++ libpython-dev python-numpy swig git libsqlite3-dev libi2c-dev libusb-1.0-0-dev libwxgtk3.0-dev freeglut3-dev

Install SoapySDR

git clone https://github.com/pothosware/SoapySDR.git
cd SoapySDR
git pull origin master
mkdir build && cd build
cmake ..
make -j4
sudo make install
sudo ldconfig

Install LimeSDR

git clone https://github.com/myriadrf/LimeSuite.git
cd LimeSuite
mkdir build && cd build
cmake ..
make -j4
sudo make install
sudo ldconfig
cd ../udev-rules/
sudo ./install.sh
# Download board firmware
sudo LimeUtil --update

Now, we can implement all the tuto made for USRP, changing a few parameters

Compile OpenAirInterface softmodem, as for USRP

./cmake_targets/build_oai -c -w LMSSDR --eNB --UE

To run, you need a config file specific for the LimeSDR board

./cmake_targets/lte_build_oai/build/lte-softmodem -d -O enb.conf --rf-config-file targets/ARCH/LMSSDR/LimeSDR_above_1p8GHz_1v4.ini

This config file is for 1v4 or 1v4s LimeSDR board revision (revision is written on the board).

The connector to use with this config file: RX1_H and TX1_2

I managed to attach a regular UE fdd band 7, but the throughput and stability is much poorer than my USRP.

I’ll try to make better radio configuration soon.