For the purposes of the present document, the definitions in 
are supplemented by the following definitions:
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.
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.
Time, typically in number of seconds, to perform the on-line mechanism used for fraud control and cost control.
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.
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.
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.
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.
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