3 Definitions, symbols and abbreviations
23.2713GPPFunctional stage 2 description of Location Services (LCS)Release 17TS
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
CAMEL: CAMEL is a network functionality, which provides the mechanisms of Intelligent Network to a mobile user.
Call Related: any LCS related operation which is associated with an established call in CS domain and a session via an active PDP context in PS domain.
Codeword: access code, which is used by a Requestor or LCS Client in order to gain acceptance of a location request for a Target UE. The codeword is part of the privacy information that may be registered by a Target UE user.
Current Location: after a location attempt has successfully delivered a location estimate and its associated time stamp, the location estimate and time stamp is referred to as the "current location" at that point in time.
Deferred location request: location request where the location response (responses) is (are) required after a specific event has occurred. The event may or may not occur immediately.
Global Navigation Satellite System: Global Navigation Satellite System (GNSS) consists of three functional elements: Space Segment (satellites), User Segment (receivers), and Control Segment (maintenance etc.). The GNSS receiver calculates its own position based on the received time differences for several satellites. GNSS include Global Positioning System (GPS) and GALILEO.
Immediate location request: location request where a single location response only is required immediately
Initial Location: in the context of an originating emergency call the location estimate and the associated time stamp at the commencement of the call set-up is referred to as "initial location".
Last Known Location: current location estimate and its associated time stamp for Target UE stored in the LCS Server is referred to as the "last known location" and until replaced by a later location estimate and a new time stamp is referred to as the "last known location".
LCS (LoCation Services): LCS is a service concept in system (e.g. GSM or UMTS) standardization. LCS specifies all the necessary network elements and entities, their functionalities, interfaces, as well as communication messages, due to implement the positioning functionality in a cellular network. Note that LCS does not specify any location based (value added) services except locating of emergency calls.
LCS Client: software and/or hardware entity that interacts with a LCS Server for the purpose of obtaining location information for one or more Mobile Stations. LCS Clients subscribe to LCS in order to obtain location information. LCS Clients may or may not interact with human users. The LCS Client is responsible for formatting and presenting data and managing the user interface (dialogue). The LCS Client may reside in the Mobile Station (UE).
LCS Client Access barring list: optional list of MSISDNs per LCS Client where the LCS Client is not allowed to locate any MSISDN therein.
LCS Client Subscription Profile: collection of subscription attributes of LCS related parameters that have been agreed for a contractual period of time between the LCS client and the service provider.
LCS Feature: capability of a PLMN to support LCS Client/server interactions for locating Target UEs.
LCS QoS Class: The QoS class determines the degree of adherence to the quality of service information as required by the source of a location request.
LCS Server: software and/or hardware entity offering LCS capabilities. The LCS Server accepts requests, services requests, and sends back responses to the received requests. The LCS server consists of LCS components, which are distributed to one or more PLMN and/or service provider.
LDR reference number: the identity which is assigned and maintained by the H-GMLC and circulated between the LCS Client, R-GMLC, H-GMLC, V-GMLC, MSC/SGSN and UE. With the identity of the UE, the LDR reference number can unique identify a Location Deferred Request. Notes: UE is involved only when the event type of the deferred request is "change of area" or "periodic location". In addition, in a Periodical Immediate/deferred LCS Service Request, the LDR reference number is exclusive.
Linear Distance Threshold: a straight line distance used for a deferred location request for the motion event. The linear distance threshold is defined by the LCS client and triggers a motion event when a UE moves by more than this distance from a previous location. The linear distance threshold is equivalent to a change of area event for leaving an area where the area is a circle with the linear distance threshold as a radius and centred on the previous location.
Local Information: information related to a given location, or general information, which is made available in a given location.
Local Service: service, which can be exclusively provided in the current serving network by a Value added Service Provider.
Location (Based) Application: location application is an application software processing location information or utilizing it in some way. The location information can be input by a user or detected by network or UE. Navigation is one location application example.
Location Based Service (LBS): service provided either by teleoperator or a 3rd party service provider that utilizes the available location information of the terminal. Location Application offers the User Interface for the service. LBS is either a pull or a push type of service (see Location Dependent Services and Location Independent Services). In ETSI/GSM documentation of SoLSA, LBS is called "Location Related Service". ETSI and/or 3GPP -wide terminology harmonization is expected here.
Location Dependent Service: service provided either by teleoperator or a 3rd party service provider that is available (pull type) or is activated (push type) when the user arrives to a certain area. It doesn’t require any subscription in advance, but the push type activation shall be confirmed by the user. The offered service itself can be any kind of service (e.g. a public Xerox machine or the discount list in a store).
Location Estimate: geographic location of an UE and/or a valid Mobile Equipment (ME), expressed in latitude and longitude data. The Location Estimate shall be represented in a well-defined universal format. Translation from this universal format to another geographic location system may be supported, although the details are considered outside the scope of the primitive services. The location estimate may include the velocity of the UE.
Location Identifier: information about the current location of the UE in the network. Location is indicated in network terms, for example using the global cell id in cellular networks, line-id in fixed broadband networks, the (MAC) address of the WLAN AP or Location Object as defined by IETF RFC 4119 [40], (OMA-Location also uses this term, but OMA so far defines the Location Identifier only for cellular access).
Location Independent Service: service provided either by teleoperator or a 3rd party service provider that is available and therefore can be activated anywhere in the network coverage. It is activated by the user’s request or by other user’s activated service, and therefore it requires a subscription in advance (pull type). The offered service itself can be any kind of service (e.g. MMS, SWDL, or LBS!).
Location Retrieval Function (LRF): this functional entity handles the retrieval of location information for the UE including, where required, interim location information, initial location information and updated location information. The LRF may interact with a separate RDF or contain an integrated RDF in order to obtain routing information. The LRF may interact with a separate GMLC or contain an integrated GMLC in order to obtain location information. The LRF may interact with or contain other types of location server functions in order to obtain location information.
Maximum reporting time: maximum allowed time between successive area/motion event reports. Expiration of the maximum reporting time triggers a report, the UE indicates expiration of the maximum reporting time as the trigger event.
Minimum reporting time: minimum allowed time between successive area/motion event reports. The UE defers any event report if needed until minimum reporting time expires.
Mobile Assisted positioning: any mobile centric positioning method (e.g. IPDL-OTDOA, E-OTD, GPS) in which the UE provides position measurements to the network for computation of a location estimate by the network. The network may provide assistance data to the UE to enable position measurements and/or improve measurement performance.
Mobile Based positioning: any mobile centric positioning method (e.g. IPDL-OTDOA, E-OTD, GPS) in which the UE performs both position measurements and computation of a location estimate and where assistance data useful or essential to one or both of these functions is provided to the UE by the network. Position methods where an UE performs measurements and location computation without network assistance data are not considered within this category.
Mobile Station: mobile station (MS) consists of Mobile or User Equipment (ME or UE) with a valid SIM or USIM attached. The abbreviation "UE" in this specification refers both to MS and User Equipment, see below.
MO-LR Short Circuit: use of an MO-LR based procedure to provide a location estimate directly from the UE to the serving SGSN or MSC using a Mobile Based positioning method (e.g. GPS) according to the requested LCS QoS and that is not obtained or verified by the RAN.
Network-based positioning: a positioning method (i.e. UTDOA) in which multiple network nodes (e.g. LMUs) perform position radio measurements based on UL transmissions from a mobile terminal to provide them to an E‑SMLC for computation of a location estimate for the mobile terminal.
Non-dialable call back number: In case of a SIM-less emergency call, or a non-registered (U)SIM emergency call, a non-dialable callback number shall be used to identify the target UE. The format and structure of the non-dialable callback number is according to national or regional regulations.
Non-registered (U)SIM emergency call: The emergency call where the U(SIM) has not been authenticated and have not been registered in the VLR. Examples of such cases could be emergency call from a blocked (U)SIM due to mistyped PIN, or when the UE is in "enter PIN" mode, or the emergency call is performed in another network with no roaming agreement with the home PLMN. Any IMSI retrieved from such a (U)SIM cannot be trusted and so cannot be used to identify the calling party.
PLMN Access barring list: optional list of MSISDN per PLMN where any LCS Client is not allowed to locate any MSISDN therein except for certain exceptional cases.
Positioning (/location detecting): positioning is a functionality, which detects a geographical location and optionally, velocity (of e.g. a mobile terminal).
Positioning method (/locating method): method or technical solution, which is used to get an estimate of the target mobile’s geographical location. For example positioning methods based on radio cell coverage, GPS or Assisted GPS methods, which are based on the Time-Of-Arrival (TOA) algorithm, and UTDOA, OTDOA or E-OTD methods, which are based on the Time-Difference-Of-Arrival (TDOA) algorithm. The positioning methods are further described in E-UTRAN Stage 2, TS 36.305 [42], UTRAN Stage 2, TS 25.305 [1] and GERAN Stage 2, TS 43.059 [16].
Predefined area: geographical area, which is not related to cell or radio coverage. The mobile may take special action when it recognises it has entered or left a predefined area.
Privacy Class: list of LCS Clients defined within a privacy exception class to which permission may be granted to locate the target UE. The permission shall be granted either on activation by the target UE or permanently for a contractual period of time agreed between the target UE and the service provider.
Privacy Exception List: list consisting of various types of privacy classes (i.e. operator related, personal etc.). Certain types of classes may require agreement between the service provider and the target UE.
Privacy Profile Register, PPR: The PPR stores privacy information of the target mobile. The PPR also executes privacy checks and sends the privacy check results to other network elements using the Lpp interface. PPR may be a standalone network entity or the PPR functionality may be integrated in H-GMLC.
Prohibited area: area where the mobile must not activate its transmitter. The Prohibited area may be a Predefined area described above or related to radio cell(s).
Pseudo-external identity: The pseudo-external identity is not the identity of real external LCS client but the identity, which is used for notifying the result of the enhanced privacy check. The pseudo-external identity shall keep the compatibility with pre Rel-6 privacy mechanisms, which does not understand privacy check result made by H-GMLC/PPR. Each operator defines its own the pseudo-external identities.
Pseudonym: A fictitious identity, which may be used to conceal the true identity (i.e. MSISDN and IMSI) of a target UE from the requestor and the LCS client.
Pseudonym mediation device: Functionality that verifies pseudonyms to verinyms.
Request id: identity which is used to identify the correspondence of a location request to multiple responses when the Response method is ASYNC. Each receiving GMLC (R-GMLC or V-GMLC or H-GMLC) allocates and maintains the Request id to identify each ASYNC location request, and includes it in the responses to the source entity of the location request (i.e. LCS client or GMLC).
Requestor: the originating entity which has requested the location of the target UE from the LCS client.
Requestor Identity: This identifier is identifying the Requestor and can be e.g. MSISDN or logical name.
Response method: method how a GMLC, which receives a location request message from another entity (i.e. LCS client or GMLC), responds to the location request. There are two methods, synchronous (SYNC) and asynchronous (ASYNC). When the requesting entity wishes multiple responses (either about one or several target UE’s location) to a single location request the procedure is ASYNC and when the requesting entity wishes a single response the procedure is SYNC. The source entity of the location request (i.e. LCS client or GMLC) can choose a preferred method and informs the method to the receiving GMLC. However, the selection of the method used is made by the receiving GMLC and when the ASYNC method is selected the Request id is notified to the source entity. The receiving GMLC can turn a SYNC request into an ASYNC procedure, e.g. in an overload situation, and the source entity (i.e. LCS client or GMLC) should be able to receive multiple responses even though the request was SYNC.
Routing Determination Function (RDF): The functional entity, which may be integrated in a Location Server (e.g. GMLC) or in an LRF, provides the proper PSAP destination address to the E-CSCF for routing the emergency request. It can interact with a location functional entity (e.g. GMLC) to manage ESQK allocation and management, and deliver location information to the PSAP.
Service Area Identifier (SAI): information, which is used to identify an area consisting of one or more cells belonging to the same Location Area, see TS 25.413 [14]. Such an area is called a Service Area and can be used for indicating the location of a UE to the CN. For this specification, only a Service Area that is defined to be applicable to the PS and CS domains shall be used.
Service coverage: a list of country codes where an LCS client offers its location services. Country code in this context means E.164 country code for a geographic area [35a].
Service Type: attribute of specific location based service provided by the LCS client, as defined in TS 22.071 [4].
Serving cell identity: the Cell Global Identification (CGI), see TS 23.003 [17], of the cell currently used by the target UE, e.g. for an emergency call in A-mode.
SIM-less emergency call: The emergency call that is originated from a UE, which does not have a SIM or USIM.
Subscription Profile: profile detailing the subscription to various types of privacy classes.
Target area: geographical area which is used for change of area type deferred location request. The target area is defined by the LCS client and is expressed as geographical area using a shape defined in TS 23.032 [11], as a geographical area using local coordinate system, as an E.164 country code for a geographic area [35a], as a PLMN identity or as a geopolitical name of the area (e.g. London).
Target UE: UE being positioned.
User Equipment: term ‘User Equipment’, or ‘UE’, as defined in TR 21.905 [3]. UE in this specification may also refer to a Mobile Equipment or User Equipment used for emergency calls, that do not have valid SIM or USIM.
Velocity: The speed of a UE and the direction in which it is travelling, encoded as defined in TS 23.032 [11]. Velocity may be defined as either 2-D (horizontal) velocity or 3-D (horizontal and vertical) velocity. Both 2-D and 3-D velocity may be reported either with or without uncertainty.
Verinym: True identity, i.e. MSISDN or IMSI, of the target UE.
Further UMTS related definitions are given in TS 22.101 [8].
3.2 Symbols
For the purposes of the present document, the following symbols apply:
Dh Interface between LIMS-IWF and SLF
Gb Interface between 2G-SGSN and BSS
Gs Interface between MSC and SGSN
La Interface between GMLC and AAA
Lc Interface between gateway MLC and gsmSCF (CAMEL interface)
Le Interface between External User and MLC (external interface)
Lg Interface between Gateway MLC – VMSC, GMLC – MSC Server, GMLC – SGSN (gateway MLC interface)
Lgd Interface between GMLC and SGSN (Diameter based)
Lh Interface between Gateway MLC and HLR (MAP based)
Lid Interface between GMLC and PMD.
Lpp Interface between GMLC(H-GMLC) and PPR entity.
Lr Interface between Gateway MLCs
Ml Interface between the E-CSCF and LRF
Sh Interface between LIMS-IWF and HSS
SLg Interface between GMLC and MME
SLh Interface between GMLC and HSS (Diameter based)
SLs Interface between MME and E-SMLC
Um GERAN Air Interface
Uu UTRAN Air Interface
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
2G- Second Generation
3G- Third Generation
A-GNSS Assisted Global Navigation Satellite System
AAA Authentication, Authorization, Accounting
AC Admission Control
AI Application Interface (prefix to interface class method)
ANM Answer Message (ISUP)
APN Access Point Name
APN-NI APN Network Identifier
ARIB Association of Radio Industries and Business
ATD Absolute Time Difference
BCCH Broadcast Control Channel
BER Bit Error Rate
BSSID Basic Service Set Identifier
BSS Base Station Subsystem
BTS Base Transceiver Station
CAMEL Customised Application For Mobile Network Enhanced Logic
CAP CAMEL Application Part
CM Connection Management
CN Core Network
CSCF Call Service Control Function
CSE Camel Service Environment
DL Downlink
DNS Domain Name System
DRNC Drift RNC
E-CSCF Emergency CSCF
E-OTD Enhanced Observed Time Difference
E-SLP Emergency SUPL Location Platform
E-SMLC Evolved Serving Mobile Location Centre
E-STN-DR Emergency Session Transfer Number for DRVCC
FER Frame Error Rate
GERAN GSM EDGE Radio Access Network
GGSN Gateway GPRS Support Node
GMLC Gateway MLC
GNSS Global Navigation Satellite System
GPRS General Packet Radio Service
GPS Global Positioning System
HE Home Environment
H-GMLC Home-GMLC
H-LIMS-IWF Home-LIMS-IWF
HSS Home Subscriber Server
HLR Home Location Register
HPLMN Home Public Land Mobile Network
IMEI International Mobile Equipment Identity
IMS IP Multimedia Subsystem
IMSI International Mobile Subscriber Identity
IP Internet Protocol
IPDL Idle Period Downlink
IW-MT-LR Mobile Terminated Location Request for an I-WLAN
I-WLAN Interworking WLAN
LA Location Application
LAF Location Application Function
LBS Location Based Services
LCAF Location Client Authorization Function
LCCF Location Client Control Function
LCCTF Location Client Co-ordinate Transformation Function
LCF Location Client Function
LCZTF Location Client Zone Transformation Function
LCS LoCation Services
LDR Location Deferred Request
LIMS-IWF Location IMS – Interworking Function
LIR Location Immediate Request
LMU Location Measurement Unit
LRF Location Retrieval Function
LSAF Location Subscriber Authorization Function
LSBcF Location System Broadcast Function
LSBF Location System Billing Function
LSCF Location System Control Function
LSCTF Location System Co-ordinate Transformation Function
LSOF Location System Operation Function
LSPF Location Subscriber Privacy Function
LSTF Location Subscriber Translation Function
MAP Mobile Application Part
ME Mobile Equipment
MExE Mobile Execution Environment
MGCF Media Gateway Control Function
MLC Mobile Location Centre
MLP Mobile Location Protocol
MM Mobility Management
MO-LR Mobile Originated Location Request
MS Mobile Station
MSC Mobile services Switching Centre
MSISDN Mobile Station Integrated Services Data Network
MT-LR Mobile Terminated Location Request
NA-ESRD North American Emergency Service Routing Digits
NA-ESRK North American Emergency Service Routing Key
NI-LR Network Induced Location Request
NPLI Network Provided Location Information
OMA Open Mobile Alliance
OSA Open Service Architecture
OTDOA Observed Time Difference Of Arrival
PC Power Control
PCF Power Calculation Function
PLMN Public Land Mobile Network
PMD Pseudonym mediation device functionality
POI Privacy Override Indicator
PPR Privacy Profile Register
PRCF Positioning Radio Co-ordination Function
PRRM Positioning Radio Resource Management
PSAP Public Safety Answering Point
PSE Personal Service Environment
PSM Power Saving Mode
PSMF Positioning Signal Measurement Function
PSTN Public Switched Telephone Network
QoS Quality of Service
RA Routing Area
RACH Random Access Channel
RAN Radio Access Network
RANAP Radio Access Network Application Part
R-GMLC Requesting-GMLC
RDF Routing Determination Function
RIS Radio Interface Synchronization
R-LIMS-IWF Requesting-LIMS-IWF
RLP Roaming Location Protocol
RNC Radio Network Controller
RRM Radio Resource Management
RTD Real Time Difference
RTT Round Trip Time
SAI Service Area Identifier
SAT SIM Application Tool-Kit
SCCP Signalling Connection Control Part
SCS Service Capability Server
SGSN Serving GPRS Support Node
SI Service Interface (prefix to interface class method)
SIM Subscriber Identity Module
SIP Session Initiation Protocol
SIP-URI SIP Uniform Resource Identifier
SIR Signal Interference Ratio
SLF Subscription Locator Function
SLP SUPL Location Platform
SLPP Subscriber LCS Privacy Profile
SMLC Serving Mobile Location Centre
SMS Short Message Service
SP Service Point
SRNC Serving RNC
SS7 Signalling System No 7
SUPL Secure User Plane Location
TA Timing Advance
TAU Tracking Area Update
TEL-URL Telephone Uniform Resource Locator
TMSI Temporary Mobile Subscriber Identity
TOA Time Of Arrival
TTTP Transfer To Third Party
UDT SCCP Unitdata message
UE User Equipment
UL Uplink
UMTS Universal Mobile Telecommunication System
UPLI UE Provided Location Information
USIM Universal Subscriber Identity Module
UTDOA Uplink Time Difference of Arrival
UTRAN Universal Terrestrial Radio Access Network
VASP Value Added Service Provider
V-GMLC Visited -GMLC
VHE Virtual Home Environment
WCDMA Wideband Code Division Multiple Access
Further related abbreviations are given in TR 21.905 [3].