DL - 4G Americas

� Pseudonym Mediation Device
o Maps or decrypts the pseudonym (fictitious identity, which may be used to conceal the true
identity ) into the corresponding verinym (true identity i.e. IMSI or MSISDN)
� Emergency Call Service Control Function
o IMS entity responsible for interfacing with LRF to obtain location for an UE in IMS emergency
session
� Location IMS Interworking Function
o In the network where the LCS service request originates, provides the capability to route LCS
service requests based on an IMS Public User Identity (SIP-URI) to the home network of the
target user
o In the home network of the target user, responsible to determine the appropriate HSS and to
obtain the MSISDN associated with a IMS Public User Identity from the HSS
B.2.3.1 UE POSITIONING
UE positioning is an access network function (e.g. GERAN, UTRAN, E-UTRAN). An access network may
support one or more UE positioning methods, which may be same or different from another access
network. In E-UTRAN the following UE positioning methods are supported:
� Cell ID positioning method
� Enhanced Cell ID based positioning method
� OTDOA positioning method
� Network assisted GNSS (A-GNSS) positioning methods
Determining the position of a UE involves two main steps:
1. Radio signal measurements
2. Position estimate computation and optional velocity computation based on the measurements
The signal measurements may be made by the UE or the E-UTRAN. Both TDD and FDD radio interface
will be supported in E-UTRAN. The basic signals measured for terrestrial position methods are typically
the E-UTRA radio transmissions. Also other transmissions such as general radio navigation signals
including those from Global Navigation Satellites Systems can also be measured. The position estimate
computation may be made in the UE or in the E-SMLC. In UE-assisted positioning the UE perform the
downlink radio measurements and the E-SMLC estimates the UE position while in UE-based positioning
the UE performs both the downlink radio measurements and also the position estimation. The UE may
require some assistance from the network in the form of assistance data in order to perform the downlink
measurements and these are provided by the network either autonomously or upon UE requesting it.
The E-UTRAN positioning capabilities are intended to be forward compatible to other access types and
other position methods, in an effort to reduce the amount of additional positioning support needed in the
future.
www.4gamericas.org February 2011 Page 122