This step is the same as step 1 of clause 6.1.2
and step 1 of clause 6.3
, with the difference that the LCS request is targeting a group of UE identified by a group ID. The NEF/GMLC may map the external group ID to the list of UE ID (i.e. SUPI) using Nudm_SDM_Get
(Group Identifier Translation, External Group Identifier) service operation.
If deferred location is requested, the GMLC responds to the LCS Client / AF with an acknowledgment.
GMLC may decide whether completely or partially (i.e. accept part of the UE(s) within the group identified by the group ID in step 1) reject the location request. If GMLC decides to partially reject the location request, GMLC will respond to the LCS client /AF with a proper error cause.
Steps 3 to 5 are carried out once per UE.
The GMLC invokes a Nudm_SDM_Get
(LCS privacy, SUPI) service operation towards the UDM to get the UE LCS privacy profile of the target UE. The GMLC checks the privacy settings. For the UE whose privacy setting does not allow it to be located, steps 4 and 5 are skipped. The GMLC may also subscribe to and receive notification of UE privacy profile updates according to steps 0 and 4 of clause 6.12.1
The GMLC invokes a Nudm_UECM_Get service operation towards the UDM of the target UE with SUPI of this UE. The UDM returns the current serving AMF ID to the GMLC.
If no AMF ID is returned at step 4:
if it is a deferred location request and the GMLC supports the storage of the LCS service request for a group of UE, the GMLC subscribes the UE reachability status to the UDM using Nudm_EventExposure_Subscribe service operation with the data key "SUPI";
otherwise, the GMLC returns an appropriate error cause to the LCS client or AF.
If the UDM returns the current serving AMF ID to the GMLC at step 4:
the GMLC initiates 5GC_MT_LR procedure (from step 4 onwards) as described in clause 6.1.2;
or the GMLC initiates Deferred 5GC-MT-LR Procedure (from step 4 onwards) as described in clause 6.3 with the difference that Step 8 is skipped.
For the deferred location request, if any UE in the group didn't get its serving AMF ID at step 4, the GMLC may store the LCS service request locally if the GMLC supports the storage of the LCS service request for a group of UE; otherwise, this step is skipped.
Further steps apply to the UEs of the group who was not registered to the network when the LCS service request is received at GMLC.
UE performs the registration as described in clause 4.2.2 of TS 23.502
during which an AMF is selected to serve the UE, and the AMF ID is stored into UDM.
UDM notifies the GMLC who had subscribed the UE registration at step 5a using Nudm_EventExposure_Notify service operation, which includes "SUPI" and UE registration status.
GMLC initiates Deferred 5GC-MT-LR Procedure (from step 2 onwards) as described in clause 6.1.3 or clause 6.3