5.2.1 Basic principles

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

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.2.1.1 General

5G connection and mobility converged charging, when activated, may be performed by the AMF interacting with CHF using Nchf specified in TS 32.290 [57] and TS 32.291 [58]. In order to provide the data required for the management activities outlined in TS 32.240 [1] (Credit-Control, accounting, billing, statistics, etc.), the AMF shall be able to perform converged charging for each of the following:

– Charging data related to registration.

– Charging data related to N2 connection between the AN and the AMF.

– Charging data related to user location.

The AMF shall use the AMF charging profile defined in clause 5.2.1.2 to determine whether charging (converged) is activated or not. The default AMF charging profile is provided by Charging Characteristics applicable to AMF are described in Annex A.

The AMF shall be able to perform converged charging by interacting with CHF, for charging data related to registration, connection and location management. The Charging Data Request and Charging Data Response are exchanged between the AMF and the CHF, based on IEC, or PEC scenarios as specified in TS 32.290 [57]. The Charging Data Request is issued by the AMF towards the CHF when certain conditions (chargeable events) are met.

The contents and purpose of each charging event that triggers interaction with CHF, as well as the chargeable events that trigger them, are described in the following clauses.

A detailed formal description of the converged charging parameters defined in the present document is to be found in TS 32.291 [58].

A detailed formal description of the CDR parameters defined in the present document is to be found in TS 32.298 [51].

5.2.1.2 Applicable Triggers in the AMF

5.2.1.2.1 General

When a charging event is issued towards the CHF, it includes details such as Subscriber identifier (e.g. SUPI).

Each trigger condition (i.e. chargeable event) defined for the 5G connection and mobility converged charging functionality, is specified with the associated behaviour when they are met.

Table 5.2.1.2.1.1 summarizes the set of default trigger conditions and their category which shall be supported by the AMF when charging is active for the corresponding AMF functionality. For "immediate report" category, the table also provides the corresponding Charging Data Request message sent from AMF towards the CHF.

Table 5.2.1.2.1.1: Default Trigger conditions in AMF

Trigger Conditions	Trigger level	Default category	CHF allowed to change category	CHF allowed to enable and disable	Message when "immediate reporting" category
Registration
Registration checked	–	Immediate	Not Applicable	Not Applicable	IEC: Charging Data Request [Event] ECUR: Charging Data Request [Initial]
Registration completed	–	Immediate	Not Applicable	Not Applicable	PEC: Charging Data Request [Event] ECUR: Charging Data Request [Termination]
Deregistration	–	Immediate	Not Applicable	Not Applicable	PEC: Charging Data Request [Event]
N2 connection
Start of N2 connection	–	Immediate	Not Applicable	Not Applicable	PEC: Charging Data Request [Event]
End of N2 connection	–	Immediate	Not Applicable	Not Applicable	PEC: Charging Data Request [Event]
Location reporting
User Location change	–	Immediate	Not Applicable	Not Applicable	PEC: Charging Data Request [Event]
Change of UE presence in Presence Reporting Area(s)	–	Immediate	Not Applicable	Not Applicable	PEC: Charging Data Request [Event]

AMF functionality charging activation/deactivation is performed by CHF via AMF charging profile update as defined in clause 5.2.1.2.3.

The AMF charging profile is defined in clause 5.2.1.2.2 and shall be used by the AMF to determine whether converged charging is active or not, and which scenario is applicable when active.

During UE initial registration in the AMF, if registration charging is active in the Charging Characteristics, a Charging Data Request [Event, Registration] or Charging Data Request [Initial, Registration] shall be sent to CHF in the corresponding charging scenario (i.e. IEC, PEC or ECUR) when applicable triggers are met. At N2 connection, if N2 connection charging is active in the AMF charging profile, a Charging Data Request [Event, N2 connection] shall be sent to CHF in PEC scenario when applicable triggers are met.

At N2 connection, if location reporting charging is active in the AMF charging profile, the AMF shall start the location reporting control procedure towards NG-RAN specified in clause 4.10 of TS 23.502 [202] for a continuous reporting whenever the UE location changes. A Charging Data Request [Event, location reporting] shall be sent by AMF upon receiving the location report from NG-RAN with current UE location.

If the AMF receives in a Charging Data Response [Event/Initial] from CHF, an updated AMF charging profile deactivating location reporting charging, and the AMF has a N2 connection, the AMF shall cancel the location reporting control procedure towards NG-RAN.

5.2.1.2.2 AMF Charging profile

An AMF charging profile is defined to allow AMF determination of applicable trigger conditions for each functionality (i.e Registration, N2 connection, Location Reporting), and includes:

– charging active or inactive;

– IEC, ECUR or PEC scenario.

For location reporting charging it includes in addition, the level for location change to be reported (i.e. TAI change and/or Cell Change), or UE presence in Presence Reporting Area(s) to be reported. The UE Presence in Presence Reporting Area (PRA) functionality is detailed in clause 5.2.1.3.

IEC and ECUR scenarios are applicable for registration only.

The AMF charging profile is per UE and per AMF.

The default AMF charging profile is provided by the Charging Characteristics which is described in Annex A.

5.2.1.2.3 Independent triggers activation

During the UE registration lifetime in the AMF, the CHF may activate/deactivate charging for any AMF functionality (i.e. Registration, N2 connection, Location Reporting) each time the CHF is invoked for a given AMF functionality. The set of triggers enabled/disabled via charging activation/deactivation by CHF are independent from the invoked AMF functionality. The triggers activation/deactivation take effect at the next AMF functionality invoking the CHF.

Table 5.2.1.2.3.1 describes the applicable messages for CHF to activate/deactivate triggers via update of AMF Charging profile:

Table 5.2.1.2.3.1: AMF charging profile update by CHF

Functionality	AMF Charging Profile field which can be updated	Message from CHF to AMF
Registration	– charging "active or inactive"	Charging Data Response [Event/Initial]
N2 connection	– charging "active or inactive"	Charging Data Response [Event/Initial]
Location Reporting	– charging "active or inactive" – level for location – list of Presence Reporting Area(s)	Charging Data Response [Event/Initial]

Functionality

AMF Charging Profile field which can be updated

Message from CHF to AMF

Registration

– charging "active or inactive"

Charging Data Response [Event/Initial]

N2 connection

– charging "active or inactive"

Charging Data Response [Event/Initial]

Location Reporting

– charging "active or inactive"

– level for location

– list of Presence Reporting Area(s)

Charging Data Response [Event/Initial]

In ECUR scenario, any update of AMF Charging Profile received in Charging Data Response [Initial] will take effect after the corresponding Charging Data Response [Termination].

5.2.1.3 UE Presence in Presence Reporting Area (PRA)

At UE initial registration in the AMF, the CHF may subscribe to changes of UE presence status(es) in PRA(s) in the Charging Data Response [Event, Registration] or Charging Data Response [Initial, Registration] respective IEC or ECUR scenarios. This subscription is performed, by activation of location reporting charging in the AMF charging profile with a list of PRAs supplied in addition.

The PRAs list may be composed of:

– Core Network pre-configured Presence Reporting Area(s) identified by PRA Identifier(s);

– UE-dedicated Presence Reporting Area(s) defined by a PRA Identifier(s) each provided with its elements.

Once location reporting charging is activated, the registration is completed, the AMF starts the location reporting procedure towards to NG-RAN specified in clause 4.10 of TS 23.502 [202] with parameters associated to the PRA(s), as described in clause 5.2.2.4.2.

When a Change of UE presence in Presence Reporting Area(s) is detected for PRA(s) subscribed-to by the CHF, the AMF sends Charging Data Request [Event, location reporting] to CHF with the PRA Identifier(s) and indication(s) whether the UE is inside or outside the Presence Reporting Area(s).

The CHF may update the list of Presence Reporting Area(s) subscription or remove the list of Presence Reporting Area(s), in any Charging Data Response [Event/Initial] as per table 5.2.1.2.3.1.