16.15.4.2.5 Uplink Rate Control

To enable faster adaptation of the uplink source rate (e.g. to handle uplink congestion), an uplink physical-layer bit rate available to a QoS flow can be suggested by the gNB via a downlink MAC CE, and the UE can also request a desired one via an uplink MAC CE.

NOTE: The bit rate is linked to the QoS flow regardless of how many cell groups are configured.

The 5GC may provide the gNB the information indicating that the QoS Flow allows rate adaptation in the uplink direction. During the Xn-based handover preparation procedure, the source gNB will forward this information for the QoS flow to the target gNB, which allows target gNB to perform uplink rate control.