22.1153GPPCharging and billingRelease 17Service aspectsTS
For the purposes of the present document, the definitions in  are supplemented by the following definitions:
Gateway UE: a UE, which acts as a gateway providing access to and from the 3GPP network for one or more non-3GPP devices that are connected to the gateway UE.
Prepay service: A prepay service allows a subscriber to pay in advance for the use of specific services, the prepay account may be updated each time the subscriber uses the services related to that account.
Real time: Time, typically in number of seconds, to perform the on-line mechanism used for fraud control and cost control.
Session: logical connection between parties involved in a packet switched based communication This term is used for IP connections rather than the term "call" that is normally used for a connection over conventional (circuit switched) systems.
Note: Information about charging is typically collected in Charging Data Records (CDR).
Local Charging Zone (LCZ): A logical grouping of a number of cells, where a special tariff applies for a select group of users. A network may have a number of LCZs. A LCZ does not necessarily need to be aligned with an LA or RA, i.e. the border of LCZ may not be the border of an LA or RA.
User: As defined in TR 21.905 : An entity, not part of the 3GPP System, which uses 3GPP System services. Example: a person using a 3GPP System mobile station as a portable telephone. Additional examples for a user in the context of this TS: a non-3GPP device connected to the 3GPP system via a gateway, or an application running on a UE.
User Identity: information representing a user in a specific context. A user can have several user identities, e.g. a User Identity in the context of his profession, or a private User Identity for some aspects of private life.
User Identifier: a piece of information used to identify one specific User Identity in one or more systems.
For the purposes of the present document the definition of abbreviations in  apply.