13 Location procedures

24.3793GPPMission Critical Push To Talk (MCPTT) call controlProtocol specificationRelease 18TS

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

13.1 General

If the participating MCPTT function needs to obtain location information, the participating MCPTT function configures the MCPTT client upon successful service authorization. The configuration contains information the MCPTT client uses to set up filter criteria for when the MCPTT client shall send location reports to the participating MCPTT function.

The participating MCPTT function can also explicitly request the MCPTT client to send a location report.

The MCPTT client will, based on the received configuration or when explicitly requested, send location reports.

The location information is used by the participating MCPTT function to determine whether to use MBMS bearers or not as described in clause 14.

13.2 Participating MCPTT function location procedures

13.2.1 General

The participating MCPTT function has procedures to:

– configure the location reporting at the UE;

– request the UE to report the location of the UE; and

– receive a location information report from the UE.

13.2.2 Location reporting configuration

The participating MCPTT function may configure the location reporting in the MCPTT client by generating a SIP MESSAGE request in accordance with 3GPP TS 24.229 [4] and IETF RFC 3428 [33]. The participating MCPTT function:

1) shall include a Request-URI set to the URI corresponding to the identity of the MCPTT client;

2) shall include an Accept-Contact header field with the media feature tag g.3gpp.icsi-ref set to the value "urn:urn-7:3gpp-service.ims.icsi.mcptt" along with parameters "require" and "explicit" in accordance with IETF RFC 3841 [6];

3) shall include an application/vnd.3gpp.mcptt-info+xml MIME body with an <mcptt-request-uri> element containing the MCPTT ID of the MCPTT user to receive the configuration;

4) shall include an application/vnd.3gpp.mcptt-location-info+xml MIME body with the <Configuration> element contained in the <location-info> root element set to the desired configuration;

5) shall include the TriggerId attribute where defined for the sub-elements defining the trigger criterion ;

6) shall include the public service identity of the participating MCPTT function in the P-Asserted-Identity header field;

7) shall include a P-Asserted-Service header field with the value "urn:urn-7:3gpp-service.ims.icsi.mcptt"; and

8) shall send the SIP MESSAGE request as specified in 3GPP TS 24.229 [4].

NOTE: The participating MCPTT function can first identify the users that have activated a functional alias. It can learn the functional aliases that are activated for an MCPTT ID from procedures specified in clause 9A.2.2.2.8.

13.2.3 Location information request

If the participating MCPTT function needs to request the MCPTT client to report its location, the participating MCPTT functions shall generate a SIP MESSAGE request in accordance with 3GPP TS 24.229 [4] and IETF RFC 3428 [33]. The participating MCPTT function:

1) shall include a Request-URI set to the URI corresponding to the identity of theMCPTT client;

3) shall include an application/vnd.3gpp.mcptt-info+xml MIME body with an <mcptt-request-uri> element containing the MCPTT ID of the MCPTT user;

4) shall include an application/vnd.3gpp.mcptt-location-info+xml MIME body with a <Request> element contained in the <location-info> root element;

5) shall include a P-Asserted-Service header field with the value "urn:urn-7:3gpp-service.ims.icsi.mcptt"; and

6) shall send the SIP MESSAGE request as specified in 3GPP TS 24.229 [4].

13.2.4 Location information report

If the participating MCPTT function receives a SIP request containing:

1) a Content-Type header field set to "application/vnd.3gpp.mcptt-location-info+xml"; and

2) an application/vnd.3gpp.mcptt-location-info+xml MIME body with a <Report> element included in the <location-info> root element;

then the participating MCPTT function shall authorise the location report based on the MCPTT ID received. If the MCPTT user is authorised to send a location report the participating MCPTT function:

1) shall use the location information as needed; and

2) shall follow the procedure of clause 6.3.2.4.1, if the MCPTT client has entered into or exited from an emergency alert area ;and

3) shall follow the procedure of clause 6.3.2.4.2, if the MCPTT client has entered into or exited from a group geographic area.

NOTE: The <Report> element contains the event triggering identity in the location information report from the UE, and can contain location information.

13.2.5 Abnormal cases

Upon receipt of a SIP request:

1) where the P-Asserted-Identity identifies a public user identity not associated with an MCPTT user served by the participating MCPTT function; or

2) with a MIME body with Content-Type header field set to "application/vnd.3gpp.mcptt-info+xml" and with a <mcptt-request-URI> element containing an MCPTT ID that identifies an MCPTT user served by the participating MCPTT function;

then, when the SIP request contains:

1) an Accept-Contact header field with the g.3gpp.mcptt media feature tag;

2) an Accept-Contact header field with the g.3gpp.icsi-ref media-feature tag with the value of "urn:urn-7:3gpp-service.ims.icsi.mcptt"; and

3) an application/vnd.3gpp.mcptt-location-info+xml MIME body containing a <Request> element or a <Configuration> element;

the participating MCPTT function shall remove the application/vnd.3gpp.mcptt-location-info+xml MIME body from the outgoing SIP request.

13.3 MCPTT client location procedures

13.3.1 General

The MCPTT client sends a location report when one of the trigger criteria is fulfilled or when it receives a request from the participating MCPTT function to send a location report. To send the location report the MCPTT client can use an appropriate SIP message that it needs to send for other reasons, or it can include the location report in a SIP MESSAGE request.

To send a location report, the MCPTT client includes in the SIP MESSAGE request an application/vnd.3gpp.mcptt-location-info+xml MIME body as specified in clause F.3. The MCPTT client populates the elements in accordance with its reporting configuration. Further location information may also be included in the P-Access-Network-Info header field.

13.3.2 Location reporting configuration

Upon receiving a SIP MESSAGE request containing:

1) an Accept-Contact header field with the media feature tag g.3gpp.icsi-ref set to the value "urn:urn-7:3gpp-service.ims.icsi.mcptt";

2) a Content-Type header field set to "application/vnd.3gpp.mcptt-location-info+xml"; and

3) an application/vnd.3gpp.mcptt-location-info+xml MIME body with a <Configuration> root element included in the <location-info> root element;

then the MCPTT client:

1) shall store the contents of the <Configuration> elements;

2) shall set the location reporting triggers accordingly; and

3) shall start the minimumReportInterval timer.

13.3.3 Location information request

Upon receiving a SIP MESSAGE request containing

1) an Accept-Contact header field with the media feature tag g.3gpp.icsi-ref set to the value "urn:urn-7:3gpp-service.ims.icsi.mcptt";

2) a Content-Type header field set to "application/vnd.3gpp.mcptt-location-info+xml"; and

3) an application/vnd.3gpp.mcptt-location-info+xml MIME body with a <Request> element included in the <location-info> root element;

then the MCPTT client:

1) shall send a location report as specified in clause 13.3.4; and

2) shall reset the minimumReportInterval timer.

13.3.4 Location information report

13.3.4.1 Report triggering

If a location reporting trigger fires the MCPTT client checks if the minimumReportInterval timer is running. If the timer is running the MCPTT client waits until the timer expires. When the minimumReportInterval timer fires, the MCPTT client:

1) shall, if any of the reporting triggers are still true, send a location information report as specified in clause 13.3.4.2.

If the MCPTT client receives a location information request as specified in clause 13.3.3, the MCPTT client shall send a location report as specified in clause 13.3.4.2.

13.3.4.2 Sending location information report

If the MCPTT client needs to send a SIP request for other reasons (e.g. a SIP MESSAGE request containing an MBMS listening report as described in clause 14), the MCPTT client:

1) shall include an application/vnd.3gpp.mcptt-location-info+xml MIME body and in the <location-info> root element the MCPTT client shall include:

a) a <Report> element and if the Report was triggered by a location request include the <ReportID> attribute set to the value of the <RequestID> attribute in the received Request;

b) <TriggerId> child elements, where each element is set to the value of the <Trigger-Id> attribute associated with the trigger that have fired; and

c) the location reporting elements corresponding to the triggers that have fired;

2) shall set the minimumReportInterval timer to the minimumReportInterval time and start the timer; and

3) shall reset all triggers.

If the MCPTT client does not need to send a SIP request for other reasons, the MCPTT client shall generate a SIP MESSAGE request in accordance with 3GPP TS 24.229 [4] and IETF RFC 3428 [33]. The MCPTT client;

1) shall include in the Request-URI, the SIP URI received in the P-Asserted-Identity header field in the received SIP MESSAGE request for location report configuration;

2) shall include a Content-Type header field set to "application/vnd.3gpp.mcptt-location-info+xml";

3) shall include an application/vnd.3gpp.mcptt-location-info+xml MIME body and in the <location-info> root element include:

a) a <Report> element and if the Report was triggered by a location request include the <ReportID> attribute set to the value of the <RequestID> attribute in the received Request;

b) a <TriggerId> child element set to the value of each <Trigger-Id> value of the triggers that have fired; and

c) the location reporting elements corresponding to the triggers that have fired;

4) shall include an Accept-Contact header field with the media feature tag g.3gpp.mcptt along with parameters "require" and "explicit" in accordance with IETF RFC 3841 [6];

5) shall set the minimumReportInterval timer to the minimumReportInterval time and start the timer;

6) shall reset all triggers; and

7) shall send the SIP MESSAGE request as specified in 3GPP TS 24.229 [4].