O-RAN Sync Standards Updates

Owned by Stefano Ruffini
Last updated: Jul 12, 2023
2 min read

The following list provides a summary on the O-RAN sync standards updates

•Control, User and Synchronization Plane Specification (CUS)

•This document specifies the control plane, user plane and synchronization plane protocols used over the fronthaul interface linking the O-DU with the O-RU.

•Latest version: ORAN.WG4.CUS.0.v12.00 – June 2023 (v13 being finalized).

•Aligned S-plane limits with ITU-T (“peak to peak”) ; Requirements for LLS-C3 aligned with ITU-T G.8271.1 (with clarification on the network requirements at the input of the O-RU)

•Fronthaul Conformance Test Specification (CONF)

•This document defines tests that validate the conformance to the O-RAN protocols for the Lower Layer Split Option 7.2x interface between the O-RU and the O-DU, including Sync Plane conformance tests.

•Latest version: ORAN.WG4.CONF.0.v08.00 –June 2023 (v09 being finalized)

•v08 includes further alignment with ITU-T; specified test methodology for LLS-C1,C2 and Specification for diagnostic O-RU 1PPS output

•v09 corrects the specification for diagnostic O-RU 1PPS output; includes details on O-RU input syncE noise ; addresses requirements for cascaded O-RUs

•Fronthaul Interoperability Test Specification (IOT)

•This document specifies the interoperability testing (IOT) for O-DU and O-RU from different vendors connected using the O-RAN fronthaul (FH) interface, including system level tests to validate both S-Plane functionality and S-Plane performance.

•Latest version : O-RAN.WG4.IOT.0-v10.00 –June 2023

•Performance tests still to be completed; it may leverage some of the updates being made in the Conf specification

•Synchronization Architecture and Solution Specification (XTRP-SYN)

•This document describes best practices for O-RAN Architecture and Solution for X-haul timing & synchronization

•Latest version: ORAN.WG9.XTRP-SYN.0.v03.00 – October 2022. Working at v04.

•New revision to enhance:

•Timing/Synchronization Redundancy & Resiliency

•Shared O-RU

•LLS C2/C3 mixed topology models

•Performance Monitoring and sync security planned for a later release

•X-Haul Transport Testing (XTRP-TST)

•This document defines the testing requirements for an Open Xhaul transport infrastructure, including Synchronization Testing

•Latest version: ORAN.WG9.XTRP-TST-v02.00 –October 2022. Working at 3.0.

•Focus on G.8275.1 (G.8275.2 for further study)

•Applicable to field tests and lab tests; For lab cases, the type and number of inserted Transport Node Elements (TNE) will be determined by operators

•New revisions will address security related tests