Software-defined End-to-End 5G Network

In this tutorial, we will show how the entire end-to-end 5G network can be simulated using software defined user equipment (UE). This allows for the evaluation of novel — non-standard compliant — algorithms and protocols.Such a setup enables you to test and prototype two-sided network functions such as AI/ML-based CSI feedback compression or even custom constellations forpilotless communications.

Ensure that you have already built the UE containeroai-nr-ue (seeOpenAirInterface Setup).

Note

For end-to-end RF experiments, this tutorial requires asecond Jetson device with another USRP connected to it. Alternatively, you can use two USRPs connected to the same Jetson. However, end-to-end simulations can be done by using OAI’srfsimulator mode.In this mode, the UE is connected to the gNB via a simulated RF interface.

Run the gNB

Before connecting the UE, the gNB needs to be ready to connect.

# start the gNB with USRP connected./scripts/start_system.shb200# or start the gNB in rfsimulator mode./scripts/start_system.shrfsim

Check that the gNB is running correctly

dockerlogs-foai-gnb

During the initialization procedure, the gNB provides the required UE parameters

136387.122571[PHY]A(nr_common_signal_proced:92)CommandlineparametersforOAIUE:-C3319680000-r106--numerology1--ssb516

These parameters depend on the choice of the configuration file of the gNB.

Run the UE

Set the above UE parameters asUE_EXTRA_OPTIONS in the.env file in the correspondingconfig directory. For the above example with 106 PRBs, theUE_EXTRA_OPTIONS should be

UE_EXTRA_OPTIONS=-r106--numerology1-C3319680000

For RF based experiments, we recommend to use the 24 or 51 PRB configurations.

Also set theUSRP_SERIAL_UE to the serial number of the USRP connected to the UE. For cable-based experiments, the two USRPs must be connected as shown inFig. 19.

Instead of using a real sim-card the UE can be configured via theconfig/common/nrue.uicc.conf file. In case you modify the IMSI, ensure it is registered in theoai_db.sql. Otherwise, the UE will not be recognized by the 5G core network.

Note that thestart_system.sh script will automatically start the UE when the gNB is running. Otherwise, you can start the UE with

# load environment variablesset-asourceconfig/b200/.envset+a# start the UE containercdconfig/common/dockercomposeup-doai-nr-ue# and shutdown the UEdockercomposestopoai-nr-ue

For RF experiments, this needs to be done on the second Jetson device.

Verify that the UE is running correctly

dockerlogs-foai-nr-ue

You should now see the UE connected to the gNB.

Test performance

Verify that an IP address was assigned

dockerexec-tioai-nr-ueifconfig

This should show a network interface with IP12.1.1.2.

Ping an external network

dockerexec-tioai-nr-ueping-Ioaitun_ue1google.com

You can access the current UE stats via

dockerexec-tioai-nr-uecatnrL1_UE_stats-0.log

Or run an end-to-end speed test via

dockerexec-doai-ext-dniperf3-s# Running uplink test (UE to gNB)dockerexec-tioai-nr-ueiperf3-u-t10-i1-b5M-B12.1.1.2-c192.168.72.135# Running downlink test (gNB to UE)dockerexec-tioai-nr-ueiperf3-u-t10-i1-b5M-B12.1.1.2-c192.168.72.135-R

You can now also run multiple UEs by adding more instances ofoai-nr-ue in thedocker-compose.yaml file to simulate a multi-user scenario.

Testing in RF Simulator Mode

The OpenAirInterface (OAI) RF simulator enables testing without access to physical radio hardware. This tutorial summarizes the basic usage for the RF simulator. For further details, see the following resources:

Basic Configuration

When launching the gNB container, include these parameters in theUSE_ADDITIONAL_OPTIONS parameter of thedocker-compose.yaml file:

--rfsimulator.options chanmod--telnetsrv

On the UE side, activate the RF-Simulator with these parameters:

--rfsimulator.options chanmod--rfsimulator.serveraddr 192.168.71.140 # <gNB_IP_ADDRESS>

You can find an example configuration file in theconfig/rfsim folder.

Dynamic Re-configuration

The RF simulator supports runtime configuration through Telnet.SeeTelnet Usage Guide for details.

To control the downlink channel (on the UE):

# Connect to UEtelnet192.168.71.1509090# View current settingschannelmodshowcurrent# View available profileschannelmodshowpredef# Set noise powerchannelmodmodify0noise_power_dB-10

To control the uplink channel (on the gNB), connect to gNB and configure uplink:

# Connect to gNBtelnet192.168.71.1409090# Set noise powerchannelmodmodify1noise_power_dB-10