The present document defines an intermediate universal Geographical Area Description which subscriber applications, GSM, UMTS, EPS or 5GS services can use and the network can convert into an equivalent radio coverage map.
For GSM, UMTS, EPS or 5GS services which involve the use of an
"area", it can be assumed that in the majority of cases the Service Requester will be forbidden access to data on the radio coverage map of a particular PLMN and that the Service Requester will not have direct access to network entities (e.g. BSC/BTS, RNC/Node B, eNB or gNB).
The interpretation by the PLMN operator of the geographical area in terms of cells actually used, cells that are partly within the given area and all other technical and quality of service aspects are out of the scope of the present document.
This specification also provides a description of velocity that may be associated with a universal Geographical Area Description when both are applied to a common entity at a common time.
The specification further provides a description of range and direction, relative location and relative velocity for a pair of devices such as 2 UEs.
The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
-
References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
-
For a specific reference, subsequent revisions do not apply.
-
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
[1]
GSM 01.04: "Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms".
[2]
GSM 04.07: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface signalling layer 3 General aspects".
[3]
Military Standard WGS84 Metric MIL-STD-2401 (11 January 1994): "Military Standard Department of Defence World Geodetic System (WGS)".
[4]
TS 29.572: "5G System; Location Management Services; Stage 3".
For the purposes of the present document, the following definitions apply.
Coordinate ID:
an identifier for a reference point that defines the origin of a particular local Cartesian System.
Local Co-ordinates:
co-ordinates relative to a local Cartesian System whose origin is expressed by a reference point. The origin may have known WGS84 coordinates. Local Co-ordinates are only applicable in 5GS.
Service Requester:
Entity, which uses the Geographical Area Description in any protocol to inform the network about a defined area.
Target:
Entity whose precise geographic position is to be described.
For the purposes of the present document, the abbreviations given in
GSM 01.04 [1] and the following apply.
GAD
Geographical Area Description
GPS
Global Positioning System
WGS
World Geodetic System
Except for local co-ordinates, the reference system chosen for the coding of locations is the World Geodetic System 1984, (WGS 84), which is also used by the Global Positioning System, (GPS). The origin of the WGS 84 co-ordinate system is the geometric centre of the WGS 84 ellipsoid. The ellipsoid is constructed by the rotation of an ellipse around the minor axis which is oriented in the North-South direction. The rotation axis is the polar axis of the ellipsoid, and the plane orthogonal to it and including the centre of symmetry is the equatorial plane.
The relevant dimensions are as follows:
Co-ordinates are then expressed in terms of longitude and latitude relevant to this ellipsoid. The range of longitude is -180° to +180°, and the range of latitude is -90° to +90°. 0° longitude corresponds to the Greenwich Meridian, and positive angles are to the East, while negative angles are to the West. 0° latitude corresponds to the equator, and positive angles are to the North, while negative angles are to the South. Altitudes are defined as the distance between the ellipsoid and the point, along a line orthogonal to the ellipsoid.
Local Co-ordinates are relative to a known reference point defined by an unique Coordinate ID configured by the PLMN operator. Local co-ordinates are then expressed in a local Cartesian co-ordinates system relative to the reference point.