Shared reference for a charging data resource for PDU sessions in communications system

A method by a charging function, CHF, of a communications system, the method comprising:

• responsive to receiving a charging data request message of a user equipment, UE, requesting attachment to a network of the communication system and containing a notification for the CHF to keep a charging data resource to track charging for network resources used for communications while the UE is attached to the network, sending a response message containing a reference for the charging data resource toward an access management function, AMF;
• responsive to receiving a charging data request message for a protocol data unit, PDU, session requested by the UE, sending a charging data response message;
• and
• tracking charging for network resources used for communications during the PDU session with the UE using the reference for the charging data resource.

An access management function, AMF, of a communications system comprising:

• at least one processor;
• and
• at least one memory coupled to the at least one processor and comprising computer readable program code that when executed by the at least one processor causes the at least one processor to perform operations configured to:
• responsive to receiving a network attach request message of a user equipment, UE, requesting attachment to a network of the communication system, send, from the AMF, a charging data request message toward a charging function, CHF, containing a notification for the CHF to keep a charging data resource to track charging for network resources used for communications associated with UE while attached to the network;
• receive, at the AMF, a response message of the CHF containing a reference for the charging data resource associated with the UE while attached to the network;
• and
• responsive to receiving a protocol data unit, PDU, session establishment request message of the UE, send, from the AMF, a PDU session establishment request message containing the reference for the charging data resource toward a session management plane function, SMF.