Karim Boutiba 3921017988 xran: fix FDD operations and avoid skipping DL/UL slots.
Previously, is_tdd_ul_symbol() and is_tdd_dl_symbol() returned true
unconditionally in FDD. This is correct for UL/DL presence (in FDD,
every symbol carries both UL and DL), but it breaks logic that relies
on the TDD property that a UL symbol is not a DL symbol (and vice
versa), e.g. the computation of the last DL symbol in mixed slots. In
FDD, this assumption does not hold, leading to incorrect behavior.

Remove the FDD shortcut from the TDD symbol helpers so they strictly
answer the TDD question, and make the FDD case explicit at each
function call (nFrameDuplexType != XRAN_FDD && ...). This harmonizes
the TDD and FDD paths: in FDD, no slot/symbol is skipped on RX or TX,
and guard-slot handling only applies to TDD.

Signed-off-by: Karim Boutiba <karim.boutiba@openairinterface.org>
2026-07-09 12:46:15 +02:00
2026-07-01 11:37:43 +02:00
2026-06-30 11:34:09 +02:00
2026-07-02 10:18:42 +02:00
2023-08-23 17:15:48 +02:00
2024-10-11 09:12:49 +02:00
2024-03-08 15:53:42 +01:00
2026-04-22 22:34:02 +02:00
2022-10-18 15:24:48 +02:00
2026-06-18 16:38:51 +02:00

Duranta OAI

License Supported OS Ubuntu 22 Supported OS Ubuntu 24 Supported OS Ubuntu 26 Supported OS RHEL9 Supported OS Fedora 44

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Duranta - OpenAirInterface

Duranta OpenAirInterface RAN delivers and maintains an open-source cellular wireless software stack for 4G, 5G and future networking technologies. It supports simulation, prototyping, and end-to-end deployments 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).

License

The source code is distributed under CSSL v1.0. Some files, such as for orchestration, are distributed under MIT license. 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:

  1. CSSL v1.0 starting tag 2026.w14
  2. OAI Public License v1.1 starting tag v1.0 till af4b0d53
  3. OAI Public License v1.0: starting tag v.04 till v1.0
  4. GPL 3: starting tag v.0 till v.04 (only initial implementation of 4G)

Where to Start

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 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 .conf format only.
  • Logs of OAI gNB/DU/CU/CU-CP/CU-UP in .log or .txt format 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 Github, so keep checking.

Always remember a structured email will help us understand your issues quickly.

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