OpenAirInterface 5G Radio Access Network Project

The scope of the OAI 5G RAN project is to build the 5G protocol stack for both gNB and UE allowing for end-to-end deployment of a 5G network.

The first target is to develop and provide the 5G Non-Stand Alone (NSA) RAN software and enable connection and traffic flow with a NSA-capable 5G commercial UE. In the NSA setting the gNB is supplemented by the LTE eNB that carries the control plane of the 5G signaling while the data bearer is set up on the gNB. A NSA capable 3GPP Rel-15 4G evolved packet core network (EPC) is connected through the S1 interface to eNB and X2-C interface enables connection between the eNB and gNB for routing and managing the flow of IP traffic. The NSA mode is also referred to as the ENDC mode and is shown here in figure.

The OAI 5G stack will support the following:

Non Stand-Alone gNB software stack

Stand-Alone gNB software stack

5G UE software stack

RAN Intelligent Controller (RIC) interfaces

CI/CD framework allowing for testing and data-center deployment of the 5G split architecture

Deployment Phases of the 5G core

The 5G RAN project consists of the following phases over the course of the two years starting summer 2020:


The first phase of development consists of a no-S1 mode which is an intermediate phase already having been implemented with preconfigured eNB and UE and configured to work without the existence of the core network,


Phase-2 which is the full NSA solution under architecture 3.x with the EPC as the core network.


The second target is the development of the 5G Stand-alone (SA) RAN software. The packet network is the 5G SA core with AMF, SMF and UPF as the main components of the 5G SA core to which the 5G gNB is connected through the Next Generation (NG) control (C-) and user (U-) plane interfaces.

The target date for the availability of the gNB supporting SA functionality is end of Q1 2021.    

OAI 5G NR Roadmap

The following chart give the status of current 5G implementations in the OAI codebase and the roadmap of future implementations.

Continuous Integration and Data Center Deployment

The OAI Engineering team will support the 5G testing and Continuous Integration (CI) effort as well as data-center deployment of the RAN components.

A Continuous Deployment (CD) framework is also under design that will leverage the 5G site at EURECOM.

RAN Programmability and RAN Splits

Although not mentioned explicitly in the development plan, RAN Intelligent Control (RIC) and split architecture for the RAN are important architectural functions of the OAI 5G RAN PG roadmap.

We shall work closely with other industry  initiatives developing specifications in this area to include them in the OAI 5G RAN stack.


To accelerate the delivery of a feature-rich and stable 5G stack, the OpenAirInterface (OAI) community launched a new sponsorship mechanism in Q1 2021 for outside parties, especially the industry, to donate financial resources to these developments. This mechanism, named the OAI 5G RAN PROJECT GROUP has been set up at the OpenAirInterface Software Alliance (OSA) with the goal of developing a 3GPP compatible 5G gNB Radio Access Network (RAN) stack as open source software for the OAI community. The project will be developed and the software distributed under the OAI Public License V1.1. The OAI 5G RAN software will provide software functions implementing all the layers including PHY, MAC, RRC, RLC, and PDCP of the 5G RAN stack specified by 3GPP. Both the gNB as well as the UE stack will be implemented for the benefit of the community. Interfaces to the outside functions like RAN Intelligent Controller (RIC) allowing RAN programmability are also part of the goals of the PROJECT GROUP.

For enquiries on how to participate in the OAI 5G RAN PROJECT GROUP, please write to: contact@openairinterface.org

Project Code

Please visit the home of the project on Gitlab: oai / openairinterface5G · GitLab (eurecom.fr)