Content for TS 23.273 Word version: 19.0.0

1… 4… 4.2… 4.2a… 4.3… 5… 5.5… 6… 6.1.2 6.1.3 6.1.4… 6.2 6.3… 6.3.2… 6.4 6.5… 6.7… 6.7.3 6.7.4 6.7.5 6.8 6.9… 6.10… 6.11… 6.12… 6.13… 6.14… 6.15… 6.16… 6.17… 6.18… 6.19… 6.19.2… 6.20… 6.20.4… 6.21… 7… 8… A… B… C…

6.19.2 Location Service Continuity between EPS and 5GS (bi-direction) for deferred MT-LR 6.19.2.1 Location Service Continuity from 5GS to EPS 6.19.2.2 Location Service Continuity from EPS to 5GS
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6.19.2 Location Service Continuity between EPS and 5GS (bi-direction) for deferred MT-LR p. 133

This clause shows the procedure to support location service continuity between EPS and 5GS (bi-direction) for deferred MT-LR. Clause 6.19.2.1 shows the procedure for 5GS to EPS handover case and clause 6.19.2.2 shows the procedure for the EPS to 5GS handover case.

Cancellation of the reporting of location events is still supported using the procedures in clause 6.3.2 and clause 6.3.3 and clauses 9.1.19.2 and 9.1.19.3 of TS 23.271, with the enhancement that for the UE or Client initiated cancel procedure in EPS, after EPC-(H)GMLC receiving LCS Cancel Service request, it also transfers the request to 5GC-(H)GMLC then 5GC-(H)GMLC initiate the cancel procedure of clause 6.3.3; for UE or Client initiated cancel procedure in 5GS, after 5GC-(H)GMLC receiving LCS Cancel Service request, it also transfers the request to EPC-(H)GMLC to release context in EPC-(H)GMLC.

6.19.2.1 Location Service Continuity from 5GS to EPS p. 133

Reproduction of 3GPP TS 23.273, Fig. 6.19.2.1-1: LCS Continuity Solution for 5GS to EPS Mobility

Figure 6.19.2.1-1: LCS Continuity Solution for 5GS to EPS Mobility

Step 1.

Same as step 1 of deferred 5GC-MT-LR procedure in clause 6.3.1, with the enhancement that 5GC-(H)GMLC obtains the LDR reference number and EPC-(H)GMLC address from EPC-(H)GMLC for the periodic or triggered location session. If the deferred LCS service request in this step contains multiple location QoS, location QoS mapping is performed by 5GC-(H)GMLC and a mapped location QoS applicable to EPS is also transferred to LMF.

Step 2.

Target UE positioning starts in 5GS with steps 2~15 of deferred 5GC-MT-LR procedure in clause 6.3.1.

If handover happens before step 16 in clause 6.3.1, the UE has not received the LCS Periodic-Triggered Invoke Request message. After handover complete, the AMF notifies 5GC-GMLC. The 5GS to EPS handover notification also includes the MME ID for the target UE. The 5GC-GMLC sends the location request with the mapped location QoS to EPC-GMLC to trigger the deferred/periodic MT-LR in EPS (i.e. steps 3-11 in clause 6.19.1.1 are performed with the enhancement in step 8 that 5GC-GMLC perform location QoS mapping, then obtain and forward the mapped location QoS which can be applicable to EPS to EPC-GMLC, the mapping may be performed by choosing the most stringent values from the "LocationQoS" and set the "LcsQoSClass" in "LocationQoS" as the "Best Effort" and with the difference that in step 9 in clause 6.19.1.1, the performed procedure is the steps 3-20 of Deferred EPC-MT-LR in clause 9.1.19.1 in TS 23.271) and steps 3a-9 are not performed;
If handover or UE movement with IDLE state happens after step 16 in clause 6.3.1, the UE has received the LCS Periodic-Triggered Invoke Request message. The UE does not release the deferred MT-LR context after handover or movement with IDLE state. The following steps 3a-9 are performed;

Step 3a.

[Conditional] In the periodic or triggered 5GC-MT-LR case, if the LCS QoS class in location request is "multiple QoS class" and there is a mapped location QoS mapped by GMLC in the location request, the LMF includes the mapped location QoS in step 3b if the access type allowed for the UE for event reporting includes "E-UTRAN connected to EPC".

Step 3b~3c.

[Conditional] In the deferred periodic or triggered 5GC-MT-LR case, LMF sends the LCS Periodical-Triggered Invoke Request to UE. If step 3a is performed, besides the multiple location QoS, the request also includes the mapped location QoS used for EPS. UE response to LMF with the LCS Periodical-Triggered Invoke Return Result.

Step 4.

[Conditional] LMF sends the Nlmf_Location_DetermineLocation Response to AMF.

Step 5.

[Conditional] UE may stay in 5GC over a period of time and the deferred 5GC-MT-LR procedure can continue in 5GS.

Step 6.

[Conditional] 5GS to EPS handover happens or UE moves to EPS with IDLE state. The LMF in 5GS does not release resource for the deferred MT-LR session after this step.

Step 7-8.

[Conditional] For the deferred periodic or triggered MT-LR case, when the event is detected by UE in EPS, the UE shall send an LCS MO-LR Invoke message for event report to the MME. If the location QoS is multiple QoS in 5GS, the UE shall include the mapped location QoS which is applicable to EPS in the LCS MO-LR Invoke message.

Step 9.

[Conditional] For the deferred periodic or triggered MT-LR case, the procedure continues with step 15-23 as described in Figure 9.1.19.1-1 of TS 23.271

Step 10-11.

[Conditional] EPC-(H)GMLC sends LCS Service Response to 5GC-(H)GMLC and 5GC-(H)GMLC performs the step 30 of Figure 6.3.1-1.

6.19.2.2 Location Service Continuity from EPS to 5GS p. 134

Reproduction of 3GPP TS 23.273, Fig. 6.19.2.2-1: LCS Continuity Solution for EPS to 5GS Mobility

Figure 6.19.2.2-1: LCS Continuity Solution for EPS to 5GS Mobility

Step 1.

Target UE positioning starts in 5GS with steps 1-3 of deferred 5GC-MT-LR for periodic, triggered and UE available location events procedure in clause 6.3.1.

Step 2.

The target UE is registered in EPC, 5GC-GMLC sends LCS Service Request to EPC-GMLC. The 5GC-GMLC derives the address of EPC-GMLC by using the mechanisms described in step 2 in clause 6.13.1.

Step 3.

Target UE positioning starts in EPS with steps 1-16 of deferred EPC-MT-LR procedure for Periodic and Triggered Location procedure in Figure 9.1.19.1-1 of TS 23.271, with enhancement that EPC-(H)GMLC obtains LDR reference number and 5GC-(H)GMLC address from 5GC-(H)GMLC for the periodic or triggered location session.

If handover happens before step 9 in clause 9.1.19.1 of TS 23.271, the UE has not received the LCS Periodic-Triggered Event Invoke message. After handover complete, the MME notifies EPC-GMLC. The EPS to 5GS handover notification also includes the AMF ID for the target UE. The EPC-GMLC sends the location request to 5GC-GMLC to trigger the deferred/periodic MT-LR in 5GS (i.e., steps 3-8 in clause 6.19.1.2 are performed with the difference that in step 6, the performed procedure is the steps 2-29 of Deferred 5GC-MT-LR procedure clause 6.3.1) and steps 4-7 are not performed;
If handover or UE movement with IDLE state happens after step 9 in clause 9.1.19.1 of TS 23.271, the UE has received the LCS Periodic-Triggered Event Invoke message. The following steps 4-7 are performed.

Step 4.

[Conditional] 5GS to EPS handover happens or UE moves to EPS with IDLE state.

Step 5-7.

[Conditional] For the deferred periodic or triggered MT-LR case, when the event is detected by UE in 5GS, the UE should send an Event Report message to the LMF through AMF.

For the deferred periodic or triggered MT-LR case, the procedure continues with steps 26-30 as described in clause 6.3.1.