Robert Schmidt
dc550ebaf6
Add SIB 3,4 support, configurable SIB2 and refactor CU/DU SIB management
This MR makes neighbour and inter-frequency configuration drive how
SIB2/SIB3/SIB4 are built and sent from CU to DUs. It standardizes SIB
payloads as byte_array_t with typed SIB IDs across RRC, F1AP and MAC,
reducing ad‑hoc buffer handling. Neighbour parsing, validation and
lookup are tightened.
Changes
- Minor refactor to gNB neighbour parsing and storage (shared PLMN
extraction, safer allocation, etc).
- Represent SIB containers uniformly as byte_array_t plus nr_sib_type_t,
and adapt F1AP, MAC and RRC users to the new container API.
- Make SIB2 cell-reselection information fully config-driven with
explicit bounds checking and SIB2 ASN.1 building from that config.
- Generate SIB3 intra-frequency neighbours from the per-cell neighbour
list and propagate them from CU to DU over F1, with MAC
decoding/attaching them to SystemInformation.
- Generate SIB4 inter-frequency neighbours from a new frequency_list
plus neighbour SIB3/SIB4 offsets, and propagate them from CU to DU
over F1, with MAC decoding/attaching them.
- Add basic ASN.1 round-trip tests for SIB2/SIB3/SIB4 and SIB4 range
checks, and update RRC docs to describe the neighbour/inter-frequency
configuration model.
Testing:
1. in gNB conf file:
cu_sibs = (2, 3, 4);
2. Update neighbour config file with SIB3/SIB4 conf:
(see documentation)
3. run gNB and UE as usual
---
Logs & configs: see MR on Gitlab
OpenAirInterface License
The source code is distributed under CSSL v1.0. Some files, such as for orchestration, are distributed under MIT license(MIT.txt). Documentation is distributed under Creative Commons Attribution 4.0 International license.
All the files without an explicit copyright header have an implicit "Copyright of OpenAirInterface Authors".
Please see NOTICE for other licenses which are used in the software.
In the past OAI source code has been re-licensed sometimes, here is the history:
- CSSL v1.0 starting tag 2026.w14
- OAI Public License v1.1 starting tag v1.0 till
af4b0d53 - OAI Public License v1.0: starting tag v.04 till v1.0
- GPL 3: starting tag v.0 till v.04 (only initial implementation of 4G)
Where to Start
- General overview of documentation
- The implemented features
- System Requirements for Using OAI Stack
- How to build
- How to run the modems
Not all information is available in a central place, and information for specific sub-systems might be available in the corresponding sub-directories. To find all READMEs, this command might be handy:
find . -iname "readme*"
RAN repository structure
The OpenAirInterface (OAI) software is composed of the following parts:
openairinterface5g
├── charts
├── ci-scripts : Meta-scripts used by the OSA CI process. Contains also configuration files used day-to-day by CI.
├── CMakeLists.txt : Top-level CMakeLists.txt for building
├── cmake_targets : Build utilities to compile (simulation, emulation and real-time platforms), and generated build files.
├── common : Some common OAI utilities, some other tools can be found at openair2/UTILS.
├── doc : Documentation
├── docker : Dockerfiles to build for Ubuntu and RHEL
├── executables : Top-level executable source files (gNB, eNB, ...)
├── maketags : Script to generate emacs tags.
├── nfapi : (n)FAPI code for MAC-PHY interface
├── openair1 : Layer 1 (3GPP LTE Rel-10/12 PHY, NR Rel-15 PHY)
├── openair2 : Layer 2 (3GPP LTE Rel-10 MAC/RLC/PDCP/RRC/X2AP, LTE Rel-14 M2AP, NR Rel-15+ MAC/RLC/PDCP/SDAP/RRC/X2AP/F1AP/E1AP), E2AP
├── openair3 : Layer 3 (3GPP LTE Rel-10 S1AP/GTP, NR Rel-15 NGAP/GTP)
├── openshift : OpenShift helm charts for some deployment options of OAI
├── radio : Drivers for various radios such as USRP, AW2S, RFsim, 7.2 FHI, ...
├── targets : Some configuration files; only historical relevance, and might be deleted in the future
└── tools : Tools for use by the developers/ci machines: code analysis and formatting
How to get support from the OAI Community
You can ask your question on the mailing lists.
Your email should contain below information:
- A clear subject in your email.
- For all the queries there should be [Query] in the subject of the email and for problems there should be [Problem].
- In case of a problem, add a small description.
- Do not share any photos unless you want to share a diagram.
- OAI gNB/DU/CU/CU-CP/CU-UP configuration file in
.confformat only. - Logs of OAI gNB/DU/CU/CU-CP/CU-UP in
.logor.txtformat only. - In case your question is related to performance, include a small description of the machine (Operating System, Kernel version, CPU, RAM and networking card) and diagram of your testing environment.
- Known/open issues are present on GitLab, so keep checking.
Always remember a structured email will help us understand your issues quickly.