DU-low

The DU-low (Distributed Unit - Low) implements the Upper PHY layer of the protocol stack. It performs channel coding and modulation for downlink transmissions, and channel estimation, equalization, and decoding for uplink receptions. The DU-low communicates with the DU-high via the FAPI interface and with the Radio Unit via the Open Fronthaul (OFH) interface, where lower PHY processing and RF functions are carried out. This architecture applies to O-RAN Split 7.2 deployments.

Components

• Upper PHY: Performs channel coding, modulation, and resource mapping for downlink, and channel estimation, equalization, and decoding for uplink.

Interfaces

Interface	Connects to
FAPI	DU-high
OFH	Radio Unit (lower PHY)