6 Service Provision

22.0713GPPLocation Services (LCS)Release 17Service descriptionStage 1TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

6.1 Identification of a Target UE

For value added services, the following is applicable:

The LCS client shall identify a target UE using the MSISDN or SIP URL.

The LCS Client shall be able to identify the target UE using IP addressing.

For PLMN operator services, the LCS client may identify a target UE using any of the following:

MSISDN

SIP URL

IMSI

An identifier internal to the PLMN

For emergency services (where required by local regulatory requirements), the LCS client may identify a target UE using any one of the following:

MSISDN

SIP URL

IMSI

NA-ESRK + (optionally) IMEI, applicable for regions using the ANSI standards

IMEI, applicable for regions using the ETSI standards

IMEI is used for unauthorized UEs or UEs without SIM/USIM. In regions using ETSI standards it shall be indicated that the use of this identification is triggered by an emergency call.

It shall be possible for the target mobile’s user to hide her true identity from the requestor and the LCS client and replace it with an alias. The alias shall be a unique identification that has a one-to-one relationship to the true identity of the subscriber and may be permanent or temporary. The target mobile user shall be able to know her own alias so that she can pass the alias to the LCS client, e.g. when invoking a location-based service.

6.2 Location Information Provided to the LCS Client

For value added services, the following is applicable:

The LCS Server shall provide, on request, the current or most recent Location Information (if available) of the Target UE or, if positioning fails, an error indication plus optional reason for the failure.

For PLMN operator services (where allowed by local regulatory requirements and restrictions on UE privacy), Location Information for a particular target UE may be provided to a PLMN operator LCS client either on request or on the occurrence of an event in the LCS server that has been defined to equate to such a request.

For emergency services (where required by local regulatory requirements), the geographic location or Dispatchable Location may be provided to an emergency services LCS Client either without any request from the client at certain points in an emergency services call (e.g. following receipt of the emergency call request, when the call is answered, when the call is released) or following an explicit request from the client. The former type of provision is referred to as a “push” while the latter is known as a “pull”. In the case of a “pull”, the emergency service LCS Client shall identify the Target UE as defined in section 6.1. Table 3 shows the information that may be provided to the client for either a “push” or a “pull”.

Table 3: Location related information provided to an emergency services LCS Client

Type of Access

Information Items

Push

Current Dispatchable Location (if available)

Current Geographic Location (if available)

MSISDN

SIP URL

IMSI

IMEI

NA-ESRK

NA-ESRD

State of emergency call – unanswered, answered, released (note 1)

Pull

Dispatchable Location (note 2), either:

Current civic location or

Initial civic location at start of emergency call Geographic location (note 2), either:

Current location or

initial location at start of emergency call

Both Dispatchable Location and geographic location (note 2), either:

Current location or

initial location at start of emergency call

NOTE 1: indication of call release means that any NA-ESRK will no longer identify the calling UE subscriber

NOTE 2: which type of location is required will be indicated by the LCS Client

6.3 LCS Client Subscription

It shall be possible for an LCS Client to subscribe to the LCS feature for third-party location with or without subscription to other services. An LCS Client may subscribe to one or more service providers’ LCS feature in one or more PLMNs. The LCS Client Subscription Profile of a client may contain the range of QoS and subscriptions that the LCS Client is allowed to request.

For certain authorized LCS Clients internal to the PLMN, a subscription profile may be unnecessary. For these LCS Clients subscription to LCS feature is given implicitly as a result of subscription to an authorized PLMN service (e.g. supplementary services). These LCS Clients are empowered to access the LCS Server and request location information for a Target UE.

For emergency services, the subscription requirements to the LCS feature may not be needed.

6.4 Target UE Subscription

6.4.1 Privacy Subscription Options

It shall be possible for a Target UE Subscriber to subscribe to various types of privacy classes. The default treatment in the absence of the information to the contrary in the Target UE Subscription Profile shall be to assume that access is restricted to all LCS Clients (unless using privacy overriding, or otherwise overridden by local regulatory requirements).

Privacy Attributes consist of:

Codeword: an additional level of security that may be set by a Target UE user to determine which Requestors are allowed to request location information;

Privacy Exception List: determines which LCS Clients, services and classes of LCS Clients may position a Target UE;

Service Type Privacy: determines whether the service type allows the LCS Clients to get the position of a Target UE;

Privacy Override Indicator: determines applicability of the Privacy Exception List.

6.4.2 Codeword

It shall be possible for a Requestor and an LCS client to request location information by indicating a Codeword associated with the Target UE user. The codeword shall be either checked by the Target UE/user or by the LCS server in the home network. In the former case, the codeword supplied by the requestor and forwarded by the LCS client with the request shall be forwarded to the Target UE/user for verification and acceptance. In the latter case, the codeword shall be registered with the LCS server by the Target UE user (or subscriber) in advance. Optionally, the UE and/or network may have the capability to generate and/or distribute codewords. The generation of codewords and the distribution of those codewords are out of scope of this specification. A comparison of the codeword sent by the Requestor and the registered codeword shall be performed. A location request shall only be accepted if this comparison is successful. In the case where the Target UE/user does not check the codeword, the codeword need not be sent to the Target UE/user. In the case where the codeword is checked by the Target UE/user, the Target UE subscriber need not register the codeword in advance.

The other privacy settings should also be checked even when the codeword has been checked.

The Target UE Subscriber may register multiple codewords for multiple requestors. Once the codeword has been set and properly distributed, the Target UE user would be protected against location requests from third parties, which do not know the appropriate codeword.

It should be possible for a Target UE subscriber to enable and disable codeword checking for each of the LCS Clients.

The codeword is applicable to the value-added services only.

6.4.2.1 Enhanced codeword

It shall be possible for the target UE/ user to secure the codeword from being misused. Only the intended requestor or LCS client shall be able to use the secured codeword.

It shall be possible for the target UE/user to ensure that the secured codeword can be used only within a specific time period, as determined by the target UE/user. It shall be possible for the target UE/user to ensure that a secured codeword can be used only a specific number of times, as determined by the target UE/user.

The user of the target UE shall not need to be involved in checking the validity of the secured codeword during the location service request. The secured codeword shall be checked by the LCS server.

6.4.3 Privacy Exception List

To support privacy, the LCS Server shall enable each Target UE Subscriber to subscribe to a “privacy exception list” containing the LCS Client identifiers, the service identifiers, classes of LCS Clients, the target subscriber notification setting (with/without notification) and the default treatment, which is applicable in the absence of a response from the Target UE for each LCS Client and service identifiers.

The privacy exception list shall support a minimum of 20 clients. For each client the privacy exception list shall support a minimum of 10 services. The maximum number of clients and services shall be determined by implementation constraints.

If the target subscriber notification is set as “notification with verification”, each positioning request from the LCS Client or the service shall be notified to the target UE before positioning. If the target subscriber notification is set as “notification with verification based on current location”, positioning requests from the LCS Client or the service shall be notified to the target UE after positioning is performed if the current location of the target UE is within the areas specified to require notification. The treatment for location request from the LCS Client or service, which is not registered in the privacy exception list, shall also be specified in the privacy exception list. An empty privacy exception list shall signify an intent to withhold location from all LCS Clients.

The classes that can be included are as follows.

– Universal Class: location services may be provided to all LCS Clients;

– Call/session-related Class: location services may be provided to any value added LCS clients or a particular value added LCS client or a particular service or particular group of value added LCS Clients – where each LCS Client, service or group of LCS Clients is identified by a unique international identification, e.g. E.164 – that currently has a temporary association with the Target UE in the form of an established voice, data call or PS session originated by the Target UE. For each identified LCS Client, service or group of LCS Clients, one of the following geographical restrictions shall apply:

a) Location request allowed from an LCS Client or service served by identified PLMN only;

b) Location request allowed from an LCS Client or service served in the home country only;

c) Location request allowed from any LCS Client or service;

– Call/session-unrelated Class; location services may be provided to a particular value added LCS Client or a particular service or particular group of value added LCS Clients – where each LCS Client, service or group of LCS Clients is identified by a unique international identification, e.g. E.164. For each identified LCS Client, service or group of LCS Clients, one of the following geographical restrictions shall apply:

a) Location request allowed from an LCS Client or service served by identified PLMN only;

b) Location request allowed from an LCS Client or service served in the home country only;

c) Location request allowed from any LCS Client or service;

– PLMN Operator Class – location services may be provided by particular types of LCS clients supported within the HPLMN or VPLMN. The following types of clients are distinguished (see note):

a) Clients broadcasting location related information to the UEs in a particular geographic area – e.g. on weather, traffic, hotels, restaurants;

b) O&M client (e.g. an Operations System) in the HPLMN

c) O&M client (e.g. an Operations System) in the VPLMN

d) Clients recording anonymous location information (i.e. without any UE identifiers) – e.g. for traffic engineering and statistical purposes

e) Clients enhancing or supporting any supplementary service, IN service, bearer service or teleservice subscribed to by the target UE subscriber.

NOTE: The definitions of the various PLMN operator categories may be supplemented by more precise language in contractual agreements both between UE subscribers and their home service providers and between individual network operators with inter-PLMN roaming agreements. Such classification of the PLMN operator categories is outside the scope of this specification.

6.4.4 Privacy Override Indicator

The privacy override indicator is applicable to lawful intercept and emergency services as allowed by local regulatory requirements. It is not applicable to value added and PLMN operator services. The Privacy Override Indicator shall be used to determine whether Subscriber Privacy of the Target UE subscriber should be overridden or not. This indicator will be set for certain special LCS Clients when it is justified. Each LCS Client shall be associated with a particular value of a position privacy override indicator during the LCS Client provisioning. The privacy override indicator is normally only valid when the LCS Server for the LCS client is located in the same country of the Target UE. If agreed by bi-lateral agreements between operators, the privacy override indicator shall also be valid when the LCS client is not located in the same country as the Target UE.

6.4.5 Subscription to Mobile Originating Location

The UE subscriber may subscribe to the following types of Mobile Originating Location (as defined in section 4):

A) Basic Self Location

B) Semi-autonomous Self Location

C) Transfer to Third Party

6.4.6 Void

6.4A Requestor

The Location Request issued by the LCS client to GMLC shall optionally include also the identity of the originator of the location request, i.e. the Requestor, not only the identity of the LCS client.

The requestor shall be authenticated by the LCS client and/or the network.

The identity of the Requestor shall be included in the privacy interrogation request. It may be either checked by an entity in the network, the Target UE or the user.

It shall be possible for the requestor to use an alias, so that the true identity of the requestor is unknown to the LCS client. The alias shall be a unique identification that has a one-to-one relationship to the true identity of the requestor and may be permanent or temporary. The LCS client shall indicate the requestor alias instead of the real requestor identity in the location request. The target mobile user in this case authorizes the requestor based on the requestor’s true identity, after it has been decrypted in the requestor’s operator’s network.

6.5 Security

The LCS Server may authorize the LCS Client. There may be security mechanisms to authorize the LCS Client’s request for locating a Target UE based on:

LCS Client access barring list(s),

PLMN/SP access barring list,

Point of origin of a location request.

6.6 Charging

The LCS Server shall enable a PLMN to charge LCS Clients for the LCS features that the PLMN provides. . The information that the operator uses to generate a bill to an LCS Client is operator or service provider specific. The charging information may be collected both for the LCS Client and for inter-network revenue sharing.

To support charging and billing for location services, additional information will need to be provided in call detail records.

Charging for value added location services may be provided on a transaction basis, periodically, or a mixture of both.

To support transaction-based charging where applicable, service associated call detail records may need to include (as a minimum) the following additional information (depending on the specific service):

Type and Identity of the LCS Client;
Identity of the target UE;
Results (e.g. success/failure, method used, position, response time, accuracy)
Time Stamp;
Type of coordinate system used.

6.7 LCS Open Service Architecture and Application Programming Interface

Note: LCS information may be accessible through the Open Service Architecture (OSA) standardized Application Programming Interface (API). OSA service aspects of LCS are described in 22.127. [6]