B.8 Retrieval of network provided location information

29.5143GPP5G SystemPolicy Authorization ServiceRelease 18Stage 3TS

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

B.8.1 General

According to clause E.7 of 3GPP TS 23.228 [33], the P-CSCF can use PCC to retrieve network provided location information. Information flows related to the distribution of network provided location information within the IMS are provided in Annex R of 3GPP TS 23.228 [33].

The following clauses provide optional PCC procedures to support the retrieval of network provided location information.

The originating P-CSCF can, depending on operator policy, retrieve the user location and/or UE Time Zone information either before sending the INVITE or MESSAGE towards the terminating side or upon reception of the SDP answer from the terminating side.

The terminating P-CSCF can, depending on operator policy, retrieve the user location and/or UE Time Zone information either upon reception of a SIP INVITE or upon reception of a SIP response.

The originating and terminating P-CSCF can, depending on operator policy, retrieve the user location and/or UE Time Zone information at mid call. e.g., when the P-CSCF learns about the access type change.

B.8.2 Retrieval of network provided location information at originating P-CSCF for inclusion in SIP Request

If the originating P-CSCF is required by operator policy to retrieve network provided location information before forwarding a SIP INVITE request, upon reception of the SIP INVITE/UPDATE request, the P-CSCF shall invoke:

– the Npcf_PolicyAuthorization_Create service operation according to clause 4.2.2.14 (SIP INVITE request); or

– the Npcf_PolicyAuthorization_Update service operation according to clause 4.2.3.14 or the Npcf_PolicyAuthorization_Subscribe service operation according to clause 4.2.6.6 (SIP INVITE/UPDATE request);

including in the corresponding HTTP request:

– an entry of the "AfEventSubscription" data type in the "events" attribute with:

a) the "event" attribute set to the value "ANI_REPORT"; and

b) the "notifMethod" attribute set to the value "ONE_TIME"; and

– the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information).

If the SIP INVITE request is an initial SIP INVITE request, the P-CSCF shall create a new "Individual Application Session Context" for the new SIP session with the Npcf_PolicyAuthorization_Subscribe service operation according to clause 4.2.6.6 (if no session information is included) or with the Npcf_PolicyAuthorization_Create service operation according to clause 4.2.2.14 (if preliminary session information is included).

The P-CSCF will receive the access network information from the PCF within the Npcf_PolicyAuthorization_Notify service operation as described in clause 4.2.5.11 and should include this access network information in the SIP INVITE/UPDATE requests that it forwards. When the retrieved access network information corresponds to the "tnapId" or "twapId" attribute, the P-CSCF may also map the retrieved access network information to a Geographical Identifier for routing, as specified in clause E.8 of 3GPP TS 23.228 [33].

If the originating P-CSCF is required by operator policy to retrieve network provided location information before forwarding a SIP MESSAGE request, upon reception of a MESSAGE request, the P-CSCF shall invoke the Npcf_PolicyAuthorization_Subscribe service operation including in the corresponding HTTP request:

– the IP address (IPv4 or IPv6) of the UE in the "ueIpv4" or "ueIpv6" attribute;

– a media component within the "medComponents" attribute including:

a) the "medCompN" attribute set to "0"; and

b) a single media subcomponent within the "medSubComps" attribute with:

i. the "flowUsage" attribute set to the value "AF_SIGNALLING"; and

ii. if the procedures for AF provisioning of AF signalling flow information do not apply, the "fNum" attribute set to "0".

– an entry of the "AfEventSubscription" data type in the "events" attribute with:

a) the "event" attribute set to the value "ANI_REPORT"; and

b) the "notifMethod" attribute set to the value "ONE_TIME"; and

– the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information).

The P-CSCF will receive the access network information from the PCF within the Npcf_PolicyAuthorization_Notify service operation as described in clause 4.2.5.11 and should include this access network information in the SIP MESSAGE requests that it forwards. When the retrieved access network information corresponds to the "tnapId" or "twapId" attribute, the P-CSCF may also map the retrieved access network information to a Geographical Identifier for routing, as specified in clause E.8 of 3GPP TS 23.228 [33].

If the AF application session context is only used for retrieval of network provided location information, at reception of this information, the AF may delete the context of application session information using the Npcf_PolicyAuthorization_ Delete service operation.

B.8.3 Retrieval of network provided location information at originating P-CSCF for inclusion in SIP response confirmation

If an originating P-CSCF is required by operator policy to retrieve network provided location information before forwarding an SDP answer, the P-CSCF shall apply the following procedures.

Upon reception of an SDP offer, the P-CSCF may invoke the Npcf_PolicyAuthorization_Create service operation to the PCF according to clause B.1 and may include in the corresponding HTTP POST request:

– an entry of the "AfEventSubscription" data type in the "events" attribute with:

a) the "event" attribute set to the value "ANI_REPORT"; and

b) the "notifMethod" attribute set to the value "ONE_TIME"; and

– the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information).

Upon reception of an SDP answer, the P-CSCF will invoke the Npcf_PolicyAuthorization_Update service operation to the PCF according to clause B.1. If the P-CSCF has not requested access network information upon reception of the SDP offer, the P-CSCF shall include in the corresponding HTTP PATCH request:

– an entry of the "AfEventSubscription" data type in the "events" attribute with:

a) the "event" attribute set to the value "ANI_REPORT"; and

b) the "notifMethod" attribute set to the value "ONE_TIME"; and

– the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information).

The P-CSCF will receive the access network information from the PCF in the Npcf_PolicyAuthorization_Notify service operation and should include this access network information in the SIP message with the response confirmation before forwarding it. When the retrieved access network information corresponds to the "tnapId" or "twapId" attribute, the P-CSCF may also map the retrieved access network information to a Geographical Identifier for routing, as specified in clause E.8 of 3GPP TS 23.228 [33].

B.8.4 Retrieval of network provided location information at terminating P-CSCF

If a terminating P-CSCF is required by operator policy to retrieve network provided location information at session establishment and/or modification, the P-CSCF shall apply the following procedures.

The terminating P-CSCF may request network provided location information upon reception of a SIP INVITE request in the following manner:

– if the SIP INVITE request is an initial SIP INVITE request, the P-CSCF shall create a new "Individual Application Session Context" for the new SIP session with the Npcf_PolicyAuthorization_Subscribe service operation according to clause 4.2.6.6 (if no session information is included) or with the Npcf_PolicyAuthorization_Create service operation according to clause 4.2.2.14 (if preliminary session information is included);

– if the SIP INVITE contains an SDP offer, the P-CSCF shall include in the corresponding HTTP request:

a) an entry of the "AfEventSubscription" data type in the "events" attribute with:

(i) the "event" attribute set to the value "ANI_REPORT"; and

(ii) the "notifMethod" attribute set to the value "ONE_TIME";

b) the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information);

c) service information derived from the SDP offer; and

d) the "servInfStatus" attribute with the value set to "PRELIMINARY"; and

– if the SIP INVITE does not contain an SDP offer, the P-CSCF shall include in the corresponding HTTP request:

a) an entry of the "AfEventSubscription" data type in the "events" attribute with:

(i) the "event" attribute set to the value "ANI_REPORT"; and

(ii) the "notifMethod" attribute set to the value "ONE_TIME"; and

b) the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information).

Upon reception of a SIP response that requires the inclusion of access network information, if the P-CSCF has not already requested network provided location information upon reception of the corresponding SIP INVITE request, the P-CSCF shall request network provided location information in the following manner:

– if an "Individual Application Session Context" related to service data has not yet been created, the P-CSCF shall create an "Individual Application Session Context" for the new SIP session with the Npcf_PolicyAuthorization_Subscribe service operation according to clause 4.2.6.6 (if no session information is included) or with the Npcf_PolicyAuthorization_Create service operation according to clause 4.2.2.14 (if session information is included);

– if the SIP response includes an SDP answer, the P-CSCF shall send an HTTP request to the PCF according to clause B.1; the P-CSCF shall include in this HTTP request:

a) an entry of the "AfEventSubscription" data type in the "events" attribute with:

(i) the "event" attribute set to the value "ANI_REPORT"; and

(ii) the "notifMethod" attribute set to the value "ONE_TIME"; and

b) the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information);

– if the SIP response does not contain an SDP body, the P-CSCF shall include in the corresponding HTTP request:

a) an entry of the "AfEventSubscription" data type in the "events" attribute with:

(i) the "event" attribute set to the value "ANI_REPORT"; and

(ii) the "notifMethod" attribute set to the value "ONE_TIME"; and

b) the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information); and

– if the SIP response includes an SDP offer, the P-CSCF shall include in the corresponding HTTP request:

– a) an entry of the "AfEventSubscription" data type in the "events" attribute with:

(i) the "event" attribute set to the value "ANI_REPORT"; and

(ii) the "notifMethod" attribute set to the value "ONE_TIME";

b) the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information);

c) service information derived from the SDP offer; and

d) the "servInfStatus" attribute with the value set to "PRELIMINARY".

The P-CSCF will receive the access network information from the PCF in the Npcf_PolicyAuthorization_Notify service operation and should include this access network information in the appropriate SIP response before forwarding it. When the retrieved access network information corresponds to the "tnapId" or "twapId" attribute, the P-CSCF may also map the retrieved access network information to a Geographical Identifier for routing, as specified in clause E.8 of 3GPP TS 23.228 [33].

If the terminating P-CSCF is required by operator policy to retrieve network provided location information upon reception of a SIP MESSAGE response, the P-CSCF shall behave according to B.8.2.

B.8.5 Provisioning of network provided location information at SIP session release

If a P-CSCF is required by operator policy to include network provided location information in SIP session release signalling, the P-CSCF shall apply the following procedures:

Upon reception of a SIP session release request that requires the inclusion of network provided location information, the P-CSCF will invoke the Npcf_PolicyAuthorization_Delete service operation to the PCF according to clause 4.2.4.6 and shall include in the HTTP request:

– an entry of the "AfEventSubscription" data type in the "events" attribute with:

a) the "event" attribute set to the value "ANI_REPORT"; and

b) the "notifMethod" attribute set to the value "ONE_TIME"; and

– the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information).

The P-CSCF will receive the access network information from the PCF in the Npcf_PolicyAuthorization_Delete service operation according to clause 4.2.4.6 and shall include this access network information in the appropriate SIP message before forwarding it. When the retrieved access network information corresponds to the "tnapId" or "twapId" attribute, the P-CSCF may also map the retrieved access network information to a Geographical Identifier for routing, as specified in clause E.8 of 3GPP TS 23.228 [33].

B.8.6 Provisioning of network provided location information at mid call

If a P-CSCF is required by operator policy to include network provided location information at mid call, the P-CSCF shall apply the following procedures:

Upon reception of a trigger (e.g., when the P-CSCF learns about the access change) that requires the inclusion of network provided location information in a SIP message, the P-CSCF will invoke the Npcf_PolicyAuthorization_Update and shall include in the corresponding HTTP request:

a) an entry of the "AfEventSubscription" data type in the "events" attribute with:

(i) the "event" attribute set to the value "ANI_REPORT"; and

(ii) the "notifMethod" attribute set to the value "ONE_TIME";

b) the "reqAnis" attribute, with the required access network information, i.e. user location and/or user time zone information);

c) service information related to the service according to clause 4.2.3.2.

The P-CSCF will receive the access network information from the PCF in the Npcf_PolicyAuthorization_Notify service operation, and should include this access network information in the appropriate SIP message before forwarding it. When the retrieved access network information corresponds to the "tnapId" or "twapId" attribute, the P-CSCF may also map the retrieved access network information to a Geographical Identifier for routing, as specified in clause E.8 of 3GPP TS 23.228 [33].