Synchronization in O-RAN
As indicated in thehttps://www.o-ran.org/ pages, “O-RAN ALLIANCE is committed to evolving Radio Access Networks with its core principles being intelligence and openness. It aims to drive the mobile industry towards an ecosystem of innovative, multi-vendor, interoperable, and autonomous RAN, with reduced cost, improved performance and greater agility.“
An Open Radio Access Network (Open RAN) is a non-proprietary version of the Radio Access Network (RAN) system that allows interoperation between cellular network equipment provided by different vendors.
Work is structured into several Working Groups, where the following groups are those particularly important from a synchronization standardization perspective:
WG4, Open Fronthaul Interface
WG9, Open X-haul Transport
WG4 deals with fronthaul related specification, e.g., as related to the synchronization of the O-RU. Relevant specifications developed by WG4 are:
•Control, User and Synchronization Plane Specification (CUS): ORAN.WG4.CUS
•Fronthaul Conformance Test Specification (CONF): ORAN.WG4.CONF
•Fronthaul Interoperability Test Specification (IOT): O-RAN.WG4.IOT
WG9 deals with the general O-RAN network and transport architectures, including specifications for X-haul timing & synchronization. Relevant synchronization related specifications developed by WG9 are:
•Synchronization Architecture and Solution Specification (XTRP-SYN): ORAN.WG9.XTRP-SYN
•X-Haul Transport Testing (XTRP-TST): ORAN.WG9.XTRP-TST
Updates from the O-RAN activities related to synchronization are summarized in the O-RAN Sync Standards updates page .
O-RAN specifications can be downloaded at this link.