The external LCS client, the NF or the AF (via an NEF) send a request to cancel the periodic or triggered location to the (H)GMLC, the external LCS client, the NF or the AF shall include the identity of the deferred request.
The HGMLC may itself initiate the cancellation procedure, e.g. when it is notified that the UE LCS privacy profile stored in the UDM was changed. For every outstanding Deferred Location Request against that UE, the HGMLC shall perform a new privacy check based on the updated UE LCS privacy profile stored in the UDM. If the privacy check passes, i.e. the LCS Client is still allowed to position the target UE, the handling of the outstanding Deferred Location Request shall be continued. Otherwise, if the privacy check does not pass, i.e. the Location estimate of the target UE is not allowed to be provided to the LCS Client, the HGMLC shall initiate a cancellation procedure
The (H)GMLC queries the UDM to determine the serving AMF address as in step 3 of clause 6.3.1
For a roaming UE, the HGMLC obtains a VGMLC address if not received at step 2 and invokes an Ngmlc_Location_CancelLocation
service operation to forward the cancellation request to the VGMLC. The (H)GMLC also includes the contact address for the (H)GMLC and the LDR reference number in the request and the latest LMF identification received in step 20 or step 29 in clause 6.3.1
if either step has occurred and included an LMF identification.
The (H)GMLC or VGMLC invokes the Namf_Location_CancelLocation service operation to forward the cancellation request to the serving AMF and includes the (H)GMLC contact address, LDR reference number and LMF identification if available.
If an LMF identification was included in step 4, the AMF forwards the cancelation request to the indicated LMF by invoking an Nlmf_Location_CancelLocation service operation and includes the (H)GMLC contact address and LDR reference number. The LMF then releases all resources for the location request.
If the UE is not currently reachable (e.g. is using eDRX or PSM), the AMF waits for the UE to become reachable.
Once the UE is reachable, if the UE is then in CM IDLE state, the AMF initiates a network triggered Service Request procedure as defined in clause 184.108.40.206 of TS 23.502
to establish a signalling connection with the UE.
The AMF sends the cancelation request to the target UE and includes the (H)GMLC contact address and the LDR reference number. The UE then releases all resources for the location request.
The UE returns an acknowledgment to the AMF.
The AMF responds to Namf_Location_CancelLocation, then V-GMLC or (H)GMLC releases all resources for the location request. AMF releases all resources for the location request.
For a roaming UE, the VGMLC responds to Ngmlc_Location_CancelLocation, then HGMLC releases all resources for the location request.
[Conditional] If the cancellation procedure is requested by HGMLC (i.e. the procedure is triggered in step 1c) and the cancelled location event is reported to external client, the NF or the AF (via NEF).