In addition to those below, abbreviations used in this 3GPP TS are listed in TR 21.905
3GPP PS Data Off
A feature which when configured by the HPLMN and activated by the user prevents transport via PDN connections in 3GPP access of all IP packets except IP packets required by 3GPP PS Data Off Exempt Services.
3GPP PS Data Off Exempt Services
A set of operator services that are allowed even if the 3GPP PS Data Off feature has been activated in the UE by the user.
This is the condition that a government decides whether applicable or not based on, e.g. a natural disaster or a man-made disaster. When this condition applies service interruptions and failures will be mitigated.
A Public Land Mobile Network (PLMN) is a network established and operated by an Administration or RPOA for the specific purpose of providing land mobile communication services to the public. It provides communication possibilities for mobile users. For communications between mobile and fixed users, interworking with a fixed network is necessary.
A PLMN may provide service in one, or a combination, of frequency bands.
As a rule, a PLMN is limited by the borders of a country. Depending on national regulations there may be more than one PLMN per country.
A relationship exists between each subscriber and his home PLMN (HPLMN). If communications are handled over another PLMN, this PLMN is referred to as the visited PLMN (VPLMN).
The PLMN area is the geographical area in which a PLMN provides communication services according to the specifications to mobile users. In the PLMN area, the mobile user can set up calls to a user of a terminating network. The terminating network may be a fixed network, the same PLMN, another PLMN or other types of PLMN.
Terminating network users can also set up calls to the PLMN.
The PLMN area is allocated to a PLMN. It is determined by the service and network provider in accordance with any provisions laid down under national law. In general, the PLMN area is restricted to one country. It can also be determined differently, depending on the different telecommunication services, or type of UE.
If there are several PLMNs in one country, their PLMN areas may overlap. In border areas, the PLMN areas of different countries may overlap. Administrations will have to take precautions to ensure that cross border coverage is minimized in adjacent countries unless otherwise agreed.
The System Area is defined as the group of PLMN areas accessible by UEs.
Interworking of several PLMNs and interworking between PLMNs and fixed network(s) permit public land mobile communication services at international level.
Regionally Provided Service
The Service Area is defined in the same way as the Service Area according to ITU-T Recommendation Q.1001 
. In contrast to the PLMN area it is not based on the coverage of a PLMN. Instead it is based on the area in which a fixed network user can call a mobile user without knowing his location. The Service Area can therefore change when the signalling system is being extended, for example.
Regionally Provided Service is defined as a service entitlement to only certain geographical part(s) of a PLMN, as controlled by the network operator.
Localised Service Area (LSA)
The localised service area concept shall give the operator a basis to offer subscribers different services (e.g. tariffs or access rights) depending on the location of the subscriber. An LSA consists of a cell or a number of cells within a PLMN. (TS 42.043
E-UTRAN utilises Tracking Areas (TA) for UE access control, location registration, paging and mobility management. The TA is independent of Location Areas (LA) and Routing Areas (RA). A TA comprises one or more E-UTRA cells Service requirements for E-UTRAN are specified in TS 22.278