OAI-5G-NR NTN Deployment Guide

This repository provides a simple, repeatable guide for deploying and testing Non-Terrestrial Network (NTN) support in OpenAirInterface (OAI) using RFsimulated GEO and LEO satellite scenarios.

Official reference documentation: https://gitlab.eurecom.fr/oai/openairinterface5g/-/blob/develop/doc/RUNMODEM.md#how-to-run-a-ntn-configuration

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Overview

This setup runs in simulated NTN mode using RFsimulator. For a complete NTN End-to-End (E2E) test, you will need:

• OAI nrUE
• RFsimulator (NTN channel simulation)
• OAI gNB
• OAI 5G Core (CN5G)

Two satellite orbit modes are supported:

1. GEO (Geostationary Orbit)
2. LEO (Low Earth Orbit) — coming soon

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Prerequisites

Before proceeding, ensure the OAI 5G Core (CN5G) is installed and running.

Setup guide: https://gitlab.eurecom.fr/oai/openairinterface5g/-/blob/develop/doc/NR_SA_Tutorial_OAI_CN5G.md

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1. GEO Satellite Simulation

Click to expand steps

Step 1 — Build OAI gNB and nrUE

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

# The NTN configuration patch is tested with the following OpenAirInterface commit:
git checkout 38dc378224d230a50a787f3d8e7d460314fcf770

cd ~/openairinterface5g/cmake_targets
./build_oai -I

sudo apt install -y libforms-dev libforms-bin

cd ~/openairinterface5g/cmake_targets
./build_oai -w SIMU --ninja --nrUE --gNB --build-lib "nrscope" -C

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Step 2 — Apply NTN Configuration

Configuration details reference: https://gitlab.eurecom.fr/oai/openairinterface5g/-/blob/develop/doc/RUNMODEM.md#gnb

Download and apply the required patch:

cd ~/openairinterface5g
wget https://raw.githubusercontent.com/ngkore/OAI-5G-NR-NTN/refs/heads/main/patch_files/ntn-geo.patch
git apply ntn-geo.patch

This patch includes all required NTN parameter changes:

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Step 3 — Run the gNB and UE

Run OAI gNB

cd cmake_targets
sudo ./ran_build/build/nr-softmodem -O ../ci-scripts/conf_files/gnb.sa.band254.u0.25prb.rfsim.ntn.conf --rfsim --rfsimulator.prop_delay 238.74

Run OAI nrUE (FDD, 5MHz BW, 15 kHz SCS)

cd cmake_targets
sudo ./ran_build/build/nr-uesoftmodem -O ../targets/PROJECTS/GENERIC-NR-5GC/CONF/ue.conf --band 254 -C 2488400000 --CO -873500000 -r 25 --numerology 0 --ssb 60 --rfsim --rfsimulator.prop_delay 238.74

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Step 4 — Test End-to-End Connectivity

UE → CN5G

ping 192.168.70.135 -I oaitun_ue1

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2. LEO Satellite Simulation

Coming soon.

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Logs

Sample logs for GEO simulation are available here

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Notes

• This guide focuses on simulation with RFsimulator.
• For real SDR NTN testing, additional configuration steps will be added later.
• Tested on OAI tag: 2026.w16