Content for &nbsp; TS 23.273 &nbsp; Word version:&nbsp; 18.5.0

Target UE positioning is started in 5GS, e.g. steps 1-12 of 5GC-MT-LR procedure in clause 6.1.2, or steps 1-5 of 5GC-MO-LR procedure in clause 6.2.

Step 2.

LMF handles the ongoing LCS session

5GS to EPS handover happens successfully as described in Figure 4.11.1.2.1-1 of TS 23.502 - AMF receives the relocation complete notification message from MME and record the target MME ID.

AMF instructs the LMF to cancel the ongoing LCS session.

The LCS Session on 5GS is cancelled by LMF.

Step 6.

LMF sends the Nlmf_Location_DetermineLocation Response to AMF after the cancellation is complete, LMF may include the current available location result in the response even it doesn't meet the requested QoS.

Figure 6.19.1.2-1: Location Service Continuity from EPS to 5GS with N26 Interface for Immediate Location Request

[Conditional] If the location request is received from 5GC-GMLC, AMF responds failure to the 5GC-GMLC with Namf_Location_ProvidePositioningInfo Response indicating failure of the LCS session with cause = HO to EPC while also including the target MME ID for the UE. The response may contain the location result from LMF at step 6.

Step 8.

[Conditional] If the step 7 is performed, the 5GC-GMLC forwards the location request to the EPC-GMLC including all the parameters of the LCS Request and the target MME ID. The location result from step 6 and 7 may also be included as one of the candidates of EPC-GMLC's location result.

Step 9.

The EPC-GMLC may reconstruct the request (e.g. area information in EUTRA for area event), it forwards the LCS Request to the Target MME received at step 8 in the case of MT-LR. The LCS session is started in EPS (e.g. steps 2-10 in Figure 9.18 of TS 23.271). In the case of MO-LR, the UE restarts the EPC-MO-LR.

Step 10.

[Conditional] If step 8 is performed, the UE location estimate is returned by the EPC-GMLC to the 5GC-GMLC

Step 11.

[Conditional] If step 10 is performed, 5GC-GMLC forwards the result from EPC-GMLC to the AF/LCS Client. AF/LCS Client is transparent to the Handover process.

6.19.1.2 Location Service Continuity from EPS to 5GS with N26 Interface for Immediate Location Request p. 126

Reproduction of 3GPP TS 23.273, Fig. 6.19.1.2-1: Location Service Continuity from EPS to 5GS with N26 Interface for Immediate Location Request

Target UE positioning is started in EPS, e.g. Steps 1-7 of EPC-MT-LR procedure in Figure 9.18 or steps 1-4 of EPC-MO-LR procedure in Figure 9.8d of TS 23.271.

Step 2.

During the EPC-MT-LR or EPC-MO-LR, EPS to 5GS handover happens successfully, as described in steps 1-14 in Figure 4.11.1.2.2.2-1 of TS 23.502 - MME receives Forward Relocation Complete Notification from the AMF and stored the AMF ID.

[Conditional] If the location request is received from EPC-GMLC, MME sends Subscriber Location Report to GMLC with Handover event type, UE identifies and AMF ID as target node information, EPC-GMLC identifies the handover by event type and target AMF.

the LCS session is cancelled as described in clause 9.1 of TS 23.271.

[Conditional] If step 3 is performed, the EPC-GMLC forwards the location request to the 5GC-GMLC including all the parameters of the LCS Request and the target AMF ID.

Step 6.

The 5GC-GMLC may reconstruct the request (e.g. convert the area information for area event), it forwards the LCS Request to the Target AMF received in the case of MT-LR. The LCS session is started in 5GS. In the case of MO-LR, the UE restarts the 5GC-MO-LR.

Figure 6.19.1.3-1: Location Service Continuity from 5GS to EPS without N26 Interface for Immediate Location Request

[Conditional] If step 5 is performed, the response is returned by the 5GC-GMLC to the EPC-GMLC.

Step 8.

[Conditional] If step 7 is performed, EPC-GMLC forwards the response from 5GC-GMLC to the LCS Client.

6.19.1.3 Location Service Continuity from 5GS to EPS without N26 Interface for Immediate Location Request p. 127

Reproduction of 3GPP TS 23.273, Fig. 6.19.1.3-1: Location Service Continuity from 5GS to EPS without N26 Interface for Immediate Location Request

Target UE positioning is started in 5GS, e.g. Steps 1-12 of 5GC-MT-LR procedure in clause 6.1.2, or steps 1-5 of 5GC-MO-LR procedure in clause 6.2.

Step 2.

[Conditional] If the 5GC-GMLC sends the message in step 4 or step 5 in Figure 6.1.2-1, 5GC-GMLC invokes the Nudm_EventExposure_Subscribe to HSS+UDM to subscribe the CN Type change event report.

LMF handles the ongoing LCS session.

5GS to EPS mobility happens successfully as described in Figure 4.11.2.2-1 of TS 23.502.

[Conditional] If step 2 is performed, the UDM detects that the CN Type of UE changes, the UDM notifies the CN Type of UE to 5GC-GMLC by invoking the Nudm_EventExposure_Notify service operation.

Step 6a.

The LMF invokes Nlmf_Location_DetermineLocation Response including failure.

Step 6b.

The AMF invokes Namf_Location_ProvidePositioningInfo Response including failure.

Figure 6.19.1.4-1: Location Service Continuity from EPS to 5GS without N26 Interface for Immediate Location Request

The steps 8~ 11 in the location service continuity from 5GS to EPS with N26 interface for immediate location request in clause 6.19.1.1 are performed in the case of MT-LR. In the case of MO-LR, the UE restarts the EPC-MO-LR procedure.

Step 8.

[Conditional] If step 2 is performed, 5GC-GMLC invokes the Nudm_EventExposure_UnSubscribe to HSS+UDM to cancel the subscription of the CN Type change event report.

6.19.1.4 Location Service Continuity from EPS to 5GS without N26 Interface for Immediate Location Request p. 128

Reproduction of 3GPP TS 23.273, Fig. 6.19.1.4-1: Location Service Continuity from EPS to 5GS without N26 Interface for Immediate Location Request

Target UE positioning is started in EPS, e.g. Steps 1-7 of EPC-MT-LR procedure in Figure 9.18, or steps 1-4 of EPC-MO-LR procedure in Figure 9.8d in TS 23.271.

Step 2a-2c.

[Conditional] If the EPC-GMLC initiates the location request, the EPC-GMLC requests the 5GC-GMLC to subscribe the CN Type change event report. The 5GC-GMLC invokes the Nudm_EventExposure_Subscribe to HSS+UDM to subscribe the CN Type change event report.

E-SMLC handles the ongoing LCS session.

EPS to 5GS mobility happens successfully as described in Figure 4.11.2.3-1 of TS 23.502.

[Conditional] If step 2 is performed, the UDM detects that the CN Type of UE changes, the UDM notifies the CN Type of UE to 5GC-GMLC by invoking the Nudm_EventExposure_Notify service operation. The 5GC-GMLC notifies the CN Type of UE to EPC-GMLC.

Step 6.

The steps 5~ 8 in the location service continuity from EPS to 5GS with N26 interface for immediate location request in clause 6.19.1.2 are performed in the case of MT-LR. In the case of MO-LR, the UE restarts the EPC-MO-LR procedure.