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Distribution Unit

The Distributed Unit (DU) is responsible for real-time baseband processing and managing the lower layers of the RAN protocol stack. It sits between the Radio Unit (O-RU) and the Central Unit (O-CU) in the O-RAN architecture.

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O-DU (O-RAN Distributed Unit)​

The Distributed Unit (DU) is a critical component of the O-RAN architecture responsible for real-time baseband processing and managing the lower layers of the protocol stack. Positioned between the Radio Unit (O-RU) and the Central Unit (O-CU), it plays a key role in reducing latency and ensuring efficient communication.

Key Responsibilities​

  • Lower Layer Management: Oversees the lower layers of the protocol stack, including the Upper Physical (PHY), MAC (Medium Access Control), and RLC (Radio Link Control) layers.
  • Data Organization and Management: Converts data into the appropriate format for efficient radio transmission and reception.
  • Scheduling: Allocates radio resources and manages user traffic to ensure low-latency performance.
  • HARQ Management: Handles Hybrid Automatic Repeat Request for error correction and retransmissions.

Connectivity​

  • Direct Interaction with the Radio Unit (O-RU): Facilitates seamless communication with the RU through the fronthaul interface (eCPRI).
  • Connects upward to the O-CU via the midhaul interface (F1 interface).

Performance and Deployment​

  • Latency Reduction and Efficiency: Positioned closer to the RU, the DU optimizes performance by managing time-sensitive protocol layers.
  • Typically deployed at cell sites or edge data centers for ultra-low latency requirements.
  • Supports virtualized or containerized implementations for cloud-native deployments.