The 5G-ORAN C-plane (control plane) is responsible for real-time control between the O-DU (O-RAN Distributed Unit) and the O-RU (O-RAN Radio Unit).

Control Plane defines the procedures:

• Scheduling and beamforming commands transfer procedure.

The scheduling and beamforming commands transfer procedure is the process of transferring scheduling and beamforming commands from the base station to the user equipment (UE). This process is essential for coordinating the transmission of data between the base station and the UE.

The scheduling and beamforming commands transfer procedure is divided into three main steps:

• Symbol numbering and duration: The base station assigns a unique symbol number and duration to each scheduling and beamforming command. This allows the UE to identify and process each command correctly.
• Scheduling command transfer: The base station transfers the scheduling commands to the UE using a dedicated control channel. The scheduling commands inform the UE which symbols it is allocated to transmit and receive data on.
• Beamforming command transfer: The base station transfers the beamforming commands to the UE using a dedicated control channel. The beamforming commands inform the UE how to focus its transmission and reception beams.
• Symbol numbering and duration

The base station assigns a unique symbol number and duration to each scheduling and beamforming command. The symbol number is a unique identifier for the command, while the duration is the length of time that the command is valid.

The symbol numbering and duration scheme is used to ensure that the UE can identify and process each command correctly. The UE uses the symbol number to identify the command, and the duration to determine how long to wait for the command to be executed.

• Mixed numerology and PRACH handling

Mixed numerology refers to the use of different numerologies (i.e., subcarrier spacing and symbol duration) within the same cell. PRACH (physical random-access channel) is a dedicated channel that UEs use to initiate random access to the base station.

• The scheduling and beamforming commands transfer procedure must be able to handle mixed numerology and PRACH. This is because UEs may be using different numerologies and/or PRACH to transmit and receive data.
• To handle mixed numerology, the base station must use a flexible symbol numbering and duration scheme. This scheme must be able to accommodate the different numerologies that are being used within the cell.

To handle PRACH, the base station must use a dedicated control channel to transfer the scheduling and beamforming commands to the UE. This control channel must be separate from the PRACH channel, to avoid interference.

Timing relations per symbol IQ in DL direction (U-Plane and C-Plane)

Timing relations per symbol IQ in UL direction (U-Plane and C-Plane)