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Architecture Overview

OCUDU provides software implementations of the O-RAN network functions that make up a gNB: the CU-CP, CU-UP, and DU. These are distinct, independently deployable components, each responsible for a specific part of the radio access protocol stack. They can be deployed together as a single gNB or distributed across separate hosts, and each can be integrated with third-party O-RAN compliant components at any of the standard interfaces.

For a conceptual introduction to the O-RAN gNB architecture, see the Knowledge Base.

OCUDU component architecture

Components​

  • CU-CP: Central Unit - Control Plane. Implements RRC and the control plane aspect of PDCP. Manages RRC connections with UEs, handles NGAP signaling with the AMF, and coordinates bearer setup with the CU-UP.
  • CU-UP: Central Unit - User Plane. Implements user plane PDCP and SDAP. Handles header compression, ciphering, and QoS flow mapping for user data, routing traffic between the UPF and the DU.
  • DU-high: Distributed Unit - High. Implements the MAC and RLC layers. MAC handles radio resource scheduling and HARQ; RLC provides segmentation and reliable in-order delivery.
  • DU-low: Distributed Unit - Low. Implements the Upper PHY layer, handling channel coding, modulation, and resource mapping at the interface between the DU-high and the Radio Unit.