Content for TS 23.271 Word version: 17.0.0

1… 5… 6… 6.2… 7… 8… 9… 9.1.1A… 9.1.2… 9.1.5… 9.1.6… 9.1.8… 9.1.9… 9.1.12… 9.1.13… 9.1.15… 9.1.19… 9.2… 9.2.2… 9.2.3… 9.3… 9.4… 9.5… 9.6… 10… 11… A… B… E F…

9.6 Mobile Originating Location 9.7 CM Procedures 9.8 Interworking with the IMS
...

9.6 Mobile Originating Location p. 158

An UE may subscribe to any of the following classes of mobile originating location:

Basic Self Location;
Autonomous Self Location;
Transfer to Third Party.

An MO-LR shall be allowed by the serving node (VMSC/MSC Server/SGSN/MME) if the type of request is supported by the appropriate subscription according to the following Table.

Table 9.3: Required UE Subscription Options for MO-LR Requests

Type of MO-LR Request	Required UE Subscription
UE requests own location	Basic Self Location
UE requests location assistance data	Autonomous Self Location
UE requests transfer of own location to another LCS Client	Transfer to Third Party

9.7 CM Procedures p. 158

9.7.1 Location request for a mobile in idle-mode p. 158

When a request for location information is received at the serving node the LCS-layer shall order paging of the UE subscriber. In case of first unsuccessful paging, normal paging procedures should apply. After successful paging the LCS-layer shall invoke the location preparation procedure.

9.7.2 Location request for a mobile in dedicated-mode p. 158

When a request for location information is received at the serving node, if the UE is already busy on CM level, the LCS-layer shall attempt to establish a parallel transaction to the existing one. If successful, the LCS-layer shall invoke the location preparation procedure.

9.8 Interworking with the IMS |R6| p. 158

9.8.1 Standard Location Request using a SIP-URI p. 158

An external LCS Client shall use the same interface to the LCS Server regardless of the target UE's identity.

If a location request from an external LCS client uses a SIP-URI as the target UE's identity, the requesting GMLC shall invoke a LIMS-IWF (Location IMS Interworking Function) to route the request to the user's home network. This routing mechanism may use standard technologies like pre-configuration of destination addresses or DNS lookups to determine the address of a LIMS-IWF in the home network of the user. The interface between two LIMS-IWF in different networks shall be Lr.

If the LIMS-IWF in the home network is not co-located with the home GMLC, it shall use the same interface towards the home GMLC as the requesting GMLC, i.e. the Lr interface. The LIMS-IWF in the home network has to determine the HSS serving the user. This may be done e.g. by a Dh SLF query or the HSS address is known to the LIMS-IWF through configuration. The LIMS-IWF retrieves the MSISDN from the HSS through Sh Pull and use MAP Send Routing Info for LCS to get the home GMLC IP address from the HLR/HSS. Afterwards the LIMS-IWF in the home network can forward the LCS service request (including the target UE's MSISDN) on the Lr interface to the home GMLC.

The following Figure shows the principle call flow when a GMLC receives a location request where the target UE's identity is an IMS Public User Identity (SIP-URI).

Reproduction of 3GPP TS 23.271, Fig. 9.9: MT-LR procedure for IMS Public User Identities

Figure 9.9: MT-LR procedure for IMS Public User Identities

Step 1.

An external LCS Client requests the current location of a target UE from a R-GMLC using the Public User Identity (SIP-URI) associated with the target UE.

Step 2.

The R-GMLC selects a LIMS-IWF in the requesting network. The LIMS-IWF address may be pre-configured or DNS is used for this purpose. The R-GMLC forwards the LCS service request to the requested LIMS-IWF via Lr interface.

Step 3.

The LIMS-IWF in the requesting network determines the LISM-IWF address in the home network. This may be done by using a pre-configured address or by DNS. The requesting LIMS-IWF forwards the LCS service request to the home LIMS-IWF via Lr interface.

Step 4.

The home LIMS-IWF queries the SLF via Dh interface to get the HSS address (using the Dh interface to retrieve the HSS address is an option).

Step 5.

The home LIMS-IWF retrieves the HSS address from the SLF via Dh SLF Response.

Step 6.

The home LIMS-IWF queries the HSS via Sh PULL (including the SIP-URI) to get the user's MSISDN.

Step 7.

The home LIMS-IWF retrieves the user's MSISDN from the HSS via Sh PULL Response.

Step 8.

The LIMS-IWF uses MAP Send Routing Info for LCS to get the H-GMLC address from the HLR/HSS.

Step 9.

The LIMS-IWF retrieves the H-GMLC address from the HLR/HSS.

Step 10.

The LCS service request is forwarded to the H-GMLC through Lr interface.

Step 11.

The H-GMLC performs the privacy check.

Step 12.

The H-GMLC queries the HLR/HSS using MAP Send Routing Info for LCS to get the V-GMLC address.

Step 13.

The H-GMLC retrieves the V-GMLC address from the HLR/HSS.

Step 14.

The H-GMLC forwards the LCS service request to the V-GMLC.

Step 15.

The standard MT-LR procedure is performed.

Step 16.

The LCS service response is send from the V-GMLC to the H-GMLC.

Step 17.

The H-GMLC performs the privacy check.

Step 18.

The LCS service response is send from the H-GMLC to home LIMS-IWF.

Step 19.

The LCS service response is send from the home LIMS-IWF to the requesting LIMS-IWF.

Step 20.

The LCS service response is send from the requesting LIMS-IWF to the R-GMLC.

Step 21.

The LCS service response is send from the R-GMLC to the external LCS Client.

9.8.2 Standard Location Request using a TEL-URL p. 160

IF a location request from an external LCS client uses a TEL-URL as the target UE's identity, the requesting GMLC shall convert the TEL-URL into a MSISDN, use this MSISDN in the location request as the target UE's address and continue with the MT-LR procedure for the PS domain.

9.8.3 Mobile Originated Location Requests in the IMS p. 160

Mobile Originated Location Requests will not specifically require IMS interworking and therefore are not covered within this specification.

9.8.4 IMS Emergency Location Procedure |R7| p. 160

A common procedure to support location and PSAP/Emergency Centre selection for any type of access network is shown in TS 23.167 "Retrieving Location information for Emergency Session". The procedure may be used dependent on the access type and the requirements of the applicable regulatory authority.