Chapter 19
User Equipment Positioning
19.1 Introduction
The ability both to locate an object and to communicate with it is a combination that enables a wide range of location-based services – from navigator-like map services to location-based advertising to tracking children, cars or even convicted criminals. This provides a natural motivation for mobile phones to have positioning capabilities. Another strong motivation is a requirement from the Federal Communications Commission (FCC) of the USA that emergency calls, whether fixed or mobile, can be located with a high degree of accuracy.
The most straightforward method by which a mobile phone can know its location is to use a GPS1 receiver operating completely independently of the cellular network. Alternatively, the cellular network itself can establish the approximate location of a connected mobile phone using knowledge of the coverage area of each cell.
The first version of LTE (Release 8) does not provide any direct protocol support for locating the User Equipment (UE). However, a Release 8 LTE UE can nonetheless be located by means of Assisted Global Navigation Satellite System (A-GNSS) and Enhanced Cell-ID-based techniques (see Sections 19.2 and 19.4 respectively) in conjunction with a general-purpose positioning protocol known as Secure User Plane Location (SUPL), defined by the Open Mobile Alliance (OMA). SUPL operates as a service in the application layer and requires only a normal User ...
