5.1 5G connection and mobility charging principles

32.2563GPP5G connection and mobility domain chargingCharging managementRelease 16Stage 2TS

5.1.1 General

The charging functions specified for the 5G connection and mobility charging, are based on functionalities supported by AMF specified in TS 23.501 [200]:

– Registration Management;

– Connection Management;

– Location Reporting.

Location Reporting is applicable to NG-RAN only.

5.1.2 Requirements

The following are high-level charging requirements specific to the 5G connection and mobility charging:

– The AMF shall support converged online and offline charging using service based interface.

– The AMF shall collect charging information per UE registration to the 5GS.

– The AMF shall collect charging information per UE N2 connection between the 5G-AN and the AMF.

– The AMF shall collect charging information per UE location reporting.

– In roaming scenario, the AMF shall collect charging information per in-bound roamer UE registration in 5GS, for both V-PLMN and Home PLMN.

5.1.3 CHF selection

The CHF Address(es) selection by the AMF is done during the Registration process based on the following options:

– CHF Address(es) used for UE context transferred from old AMF.

– CHF address(es) provided by the PCF as part of Access and mobility policy control information.

– UDM provided charging characteristics.

– NRF based discovery.

– AMF locally provisioned charging characteristics.

The priority order between these options depends on Operator’s policies.

Once selected, these CHF Address(es) shall be used as long as the UE is registered in the AMF.

5.1.4 UE Presence in Presence Reporting Area (PRA)

At UE initial registration, the CHF may subscribe to a list of Presence Reporting Area(s), to be reported with "Change of UE presence in Presence Reporting Area(s)" from AMF.

A Presence Reporting Area, as specified in TS 23.501 [200] clause 5.6.11, may represent:

– A Core Network pre-configured Presence Reporting Area identified by a PRA Identifier;

– A UE-dedicated Presence Reporting Area defined by CHF and identified by a PRA Identifier with its elements (i.e. list of TAs and/or NG-RAN nodes and/or cells identifiers).

The CHF remains subscribed to the list of Presence Reporting Area(s) as long as the UE is registered in the AMF until the list is updated or unsubscribed-to by subsequent exchanges between the AMF and the CHF.

This functionality is detailed in clause 5.2.1.3.

5.1.5 Roaming

5.1.5.1 General

Based on roaming agreements between the VPLMN and the HPLMN, for each UE determined as in-bound roamer, the AMF in VPLMN shall be able to collect charging information per UE registration, and interact with a V-CHF for CDR generation in VPLMN.

In addition, for this registration, the AMF in VPLMN may be able to interact with a H-CHF for CDR generation in HPLMN.

5.1.5.2 CHF selection

During the Registration process, for UE determined as in-bound roamer, the AMF in VPLMN can select:

– the CHF Address(es) in HPLMN based on the following options:

– UDM provided charging characteristics.

– NRF based discovery using UE identifier.

– AMF locally provisioned in charging characteristics.

– the CHF Address(es) in VPLMN based on the following options:

– NRF based discovery using the PLMN Id of the UE H-PLMN.

– AMF locally provisioned in charging characteristics.

The priority order between these options depends on Operator’s policies.