How it Works

The SMF integrates the CHF and PCF functions based on the following information:

  • Policy control request triggers that are received in the SM policy decision while PDU session is established or PCF or UE initial modification.

  • Session-level or rating-group-level charging triggers that are received while PDU session is established or in response to SMF-initiated Charging Update Request or CHF-initiated Charging Update Notify Request.

The SMF supports the following access-side information to detect the PCF and CHF triggers. The SMF sends the trigger information to the CHF and PCF during the N2-based handover.

Access-Side Information for PCF and CHF Triggers

Access-Side

CHF-Triggers

PCF-Triggers

UserLocation

USER_LOCATION_CHANGE

SAREA_CH

UeTimeZone

UE_TIMEZONE_CHANGE

SAREA_CH

ServingNetwork

PLMN_CHANGE

PLMN_CH

TargetServingNfId

SERVING_NODE_CHANGE