What is O-RAN?
O-RAN (hyphenated) specifically refers to the technical architecture and specifications produced by the O-RAN Alliance (founded 2018 by AT&T, China Mobile, Deutsche Telekom, NTT DOCOMO, and Orange). It extends the general Open RAN concept with detailed interface specifications, the RAN Intelligent Controller (RIC) framework, and the Service Management and Orchestration (SMO) platform.
How Does O-RAN Work?
The O-RAN architecture introduces: O-RU (Radio Unit), O-DU (Distributed Unit), O-CU-CP (Central Unit — Control Plane), O-CU-UP (Central Unit — User Plane). These connect via open interfaces: Open Fronthaul (O-RU to O-DU), F1 (O-DU to O-CU), E1 (O-CU-CP to O-CU-UP). The Near-RT RIC (10 ms–1 s control loop) runs xApps; the Non-RT RIC (>1 s loop) runs rApps and provides AI/ML model training.
Use Cases
Operator-led multi-vendor RAN procurement, AI-driven automatic radio resource optimisation, cloud-native RAN deployment on COTS, disaggregated supply chain resilience.
3GPP / Standards Reference
O-RAN Alliance Working Group specifications (all WGs), O-RAN Architecture Description v8.0+
Related Terms
Open RAN | Fronthaul | C-RAN | gNB
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This glossary entry is part of the 5GWorldPro Complete 5G Glossary. To go deeper into 5G architecture and technology, explore our 5G Training courses.
