OAI RAN
OAI RAN delivers and maintains an open-source cellular wireless software stack for 5G and future networking technologies. It supports simulation, prototyping, and end-to-end deployment on Commercial-Off-The-Shelf (COTS) hardware.
Built for research and experimentation, it provides standard-compliant interfaces and is released under the Collaborative Standards Software License (CSSL) within the Duranta project.
Supported features & capabilities
5G gNB (CU-DU)
- FR1 bandwidths: 10–100 MHz (numerologies 15 & 30 kHz)
- FR2 bandwidths: 100–200 MHz (numerology 120 kHz)
- Layers: up to 4 DL / 2 UL
- Modulation: 256-QAM
- Throughput: up to 1.4 Gbps DL, 400 Mbps UL
- Supports SA and NSA
5G UE
- FR1 bandwidths: all supported
- FR2 bandwidth: 100 MHz
- Layers: up to 4 DL / 2 UL
- Modulation: 256-QAM
- Throughput: up to 190 Mbps DL, 120 Mbps UL (single layer)
4G LTE
OAI also maintains a legacy 4G RAN stack, which includes:
- 4G/LTE eNB
- 4G/LTE UE
L1 capabilities
These optimizations provide a high-performance, standard-compliant Layer 1 that can be used for research, prototyping, and real-world deployments.
- Achieves up to 1.4 Gbps downlink and 400 Mbps uplink with commercial UEs
- Optimized multi-threaded processing, FFT, and encoding ensure efficiency and compliance with 3GPP standards
- Integrated benchmarking and CI testing validate performance in real-time
Non-Terrestrial Networks (NTN)
OAI extends connectivity beyond terrestrial networks
- Supports 3GPP Release 17 features for GEO and LEO satellites
- Includes SIB19, MAC HARQ enhancements, and UE frequency offset compensation
- Channels can be simulated in the RF environment
OAI NTN allows experimentation with satellite-based networks, validates NTN features, and tests end-to-end scenarios without requiring satellite hardware.
Hardware acceleration
OAI stack integrates hardware acceleration for improved performance
- NVIDIA Aerial enables full Layer-1 offload on the GPU
- Intel ACC200 and AMD Telco T2 for selective offload via the O-RAN Acceleration Abstraction Layer (AAL)
These options offer higher performance, reduce CPU load, and provide adaptability to various hardware setups for testing and deployment.
L1 inline acceleration
L1 lookaside acceleration
5G Sidelink
5G Sidelink enables direct UE-to-UE communication — with or without gNB involvement — supporting use cases such as public safety, V2X, and industrial automation. It reduces latency and extends communication to areas without network coverage.
OAI supports 2 sidelink modes:
- Mode 1: UEs under gNB coverage with gNB-managed resources
- Mode 2: UEs operating without coverage, autonomously selecting SL resources
Implemented Capabilities:
Full PHY/MAC stack support
- PHY channels: PSBCH, PSSCH, PSCCH, PSFCH
- MAC/PHY: SL-SCH, SL-BCH
- MAC/RLC: SBCCH, SCCH, STCH
End-to-end TX/RX datapath
- Basic CSI reporting
- CSI-RS support
- SINR estimation
Mode 2 MAC operation
- Basic scheduling
- Static resource-pool configuration
- Dynamic MCS selection (up to MCS 9)
- HARQ retransmissions (basic)
- Static sidelink pre-configuration via .conf files
Layer updates for sidelink IP traffic
- PDCP, RLC, and SDAP integration
Relay support
- U2N relay via 5G Sidelink Relay Adaptation Protocol (SRAP)
Split architecture
The OAI RAN stack supports 3GPP and O-RAN splits such as
- O-RAN 7.2 Open Fronthaul Interface (CUS and M planes), validated with a variety of O-RUs like Benetel, VVDN, and LITEON
- FAPI and nFAPI interfaces for modular L1 and L2 operation, including GPU acceleration through the NVIDIA Aerial platform
- 3GPP F1 and E1 splits enabling separation between CU and DUs, supporting handovers, and CU-CP/CU-UP configuration
- Additional interfaces like E2 and O1 to ensure RAN control and OAM conform with the O-RAN environment
Third-party integrations, including NVIDIA ARC-OTA and O-RAN Software Community’s High-DU integration, have been demonstrated within this framework.
Raytracing Channel Emulator
OAI developed a modular Raytracing Channel Emulator (RCE) to create realistic wireless channel conditions for 5G and 6G research. It combines a Python-based backend and a Godot-based visualization tool to model and control complex propagation environments.
The Raytracing Channel Emulator
- Enables high-fidelity, raytraced wireless channel simulations
- Integrates with the OAI RAN stack for realistic testing
- Provides APIs for scenario control and real-time data streaming
RCE modeling realistic wireless channels and propagation scenarios
Scenario setup, channel simulation, and integration with OAI RAN stack
RAN simulation
L1
Ulsim
ULSIM drives uplink traffic in the network to test user-to-base-station interactions.
rfsim
RFSIM simulates real-world radio conditions to test network behavior over the air.
RAN simulators webinar
OAI User Equipment (UE)
The OAI UE provides a fully open-source User Equipment (UE) stack
- Operates with the OAI gNB or third-party commercial gNBs
- Supports multiple bandwidths, numerologies, 256-QAM, and 2-layer MIMO in uplink and downlink
- Supports different architectures, ARM and x86
- Not only serves as a full-stack UE in simulation, but also, if needed, as an easily movable device in deployed networks
This UE stack offers a ready-to-use and fully modifiable platform for testing, debugging, and research, enabling experimentation with real-world and next-generation network scenarios.
OAI RAN and OAI UE roadmaps
The OAI Community maintains feature development roadmaps updating each quarter – Edition October 2025 below
RAN roadmap
UE roadmap