Content for  TS 23.273  Word version:  18.5.0

Steps 1-21 in clause 6.3.1 for the deferred 5GC-MT-LR procedure for periodic or triggered location are performed with the following differences.

• At step 1, the LCS Client or AF includes a request for user plane reporting in the LCS Service Request and may include a user plane address of the LCS Client or AF and security information to enable a secure connection. The H-GMLC verifies that both the target UE and the LCS Client or AF are subscribed to user plane reporting. If the LCS Client or AF did not include a user plane address or security information, the H-GMLC obtains a default user plane address and/or default security information from subscription data for the LCS Client or AF. The H-GMLC determines criteria for sending cumulative events reports over control plane. The criteria can include a cumulative event report timer and/or a maximum number of user plane event reports.
• At steps 4, 5 and 14, the request for user plane reporting, the user plane address, the security information and the criteria for sending cumulative events reports over control plane are forwarded in sequence to the V-GMLC (if used), serving AMF and LMF.
• At step 14 or step 15, the LMF gets the UE capabilities and verifies that the UE is able to support position methods that allow the UE to determine its own location.
• At step 16, the LMF includes the request for user plane reporting, the user plane address, the security information and the criteria for sending cumulative events reports in the supplementary services LCS Periodic-Triggered Invoke Request sent to the target UE.
• At step 17, the target UE indicates to the LMF whether event reporting via user plane can be supported by the target UE. If event reporting via user plane cannot be supported by the target UE, a failure response is returned to the LCS Client or AF at steps 18-21.

The UE establishes a secure user plane connection with TLS to the LCS Client or AF using the user plane address and the security information received at step 1.

The UE monitors for and detects the occurrence of a trigger or periodic event as described for step 22 of the procedure in clause 6.3.1.

The UE obtains location measurements and determines a current location.

If the UE is unable to determine its location at step 4a, the UE sends an event report to the LCS Client or AF over control plane as described for steps 24-30 in clause 6.3.1.

The UE sends an Event Report to the LCS Client or AF over the secure user plane connection established at step 2. The event report indicates the type of event being reported and includes the location determined at step 4a.

The LCS Client or AF may return an Event Report Acknowledgment to the UE over the secure user plane with TLS connection established at step 2.

The UE continues to monitor for and detect further trigger or periodic events as at step 3 and repeats steps 4-6 for each detected trigger or periodic event.

The UE monitors the criteria received at step 1 for sending of cumulative event reports. If a cumulative event report timer was received at step 1, the UE starts the timer following step 1 and after each cumulative event report is sent. If a maximum number of user plane event reports was received at step 1, the UE maintains a count of the number of user plane event reports sent at step 5. When the cumulative event report timer expires or when the count of user plane events reports sent at step 5 reaches the maximum number of user plane event reports, the UE sends a cumulative event report and restarts the timer and the count of user plane event reports. The UE sends the cumulative event report to the LMF, H-GMLC and LCS Client or AF over the control plane portion of the periodic or triggered deferred 5GC-MT-LR using steps 25-30 of the procedure in clause 6.3.1. The cumulative event report indicates to the LMF, H-GMLC and External LCS Client or AF that the control plane portion of the periodic or triggered deferred 5GC-MT-LR is still active, that the UE is reporting events via user plane and may include statistics on the events reported since the last cumulative event report was sent (e.g. the number of event reports). A target UE may also send a cumulative event report at step 8 to obtain assistance data from the LMF to assist with location at step 4a. In this case, the target UE includes a positioning LPP request for assistance data in the cumulative event report sent to the LMF at step 25 in clause 6.3.1 and the LMF uses step 27 in clause 6.3.1. to return the requested assistance data to the target UE. In this case, the cumulative event report timer and the count of user plane event reports are restarted and a cumulative event report is sent on to the H-GMLC and LCS Client or AF by the LMF (but without the embedded positioning LPP request for assistance data). During step 8, the LMF change procedure in clause 6.4 may be used to forward the cumulative event report (and any request for assistance data) to another LMF if the current LMF can no longer support the periodic or triggered MT-LR due to a change in target UE location (e.g. a change to the target UE TAI). In this case, the new LMF can return any assistance data to the UE (if this was requested) and can forward the cumulative event report to the H-GMLC and LCS Client or AF.

After the UE has sent the final event report and received an acknowledgment using steps 5 and 6 or step 4b, the UE shall release the user plane connection to the LCS Client or AF if the LCS Client or AF has not yet initiated release of the user plane connection