Content for TR 23.771 Word version: 13.0.0
5 Key issues p. 10
5.1 Key Issue #1: ePDG Selection for emergency services p. 10
5.2 Key Issue 2: Providing priority to emergency services especially in case of control plane congestion p. 10
5.3 Key Issue 3: providing location information to IMS nodes p. 10
5.4 Key Issue 4: Location Privacy p. 11
5.5 Key Issue 5: Location at Initial Connection for Voice Service p. 11
5.6 Key Issue 6: Determination of Emergency Call Support p. 11
5.7 Key Issue 7: Determine if TWAN supports emergency service p. 11
5.8 Key Issue 8: Support of unauthenticated emergency session over Trusted WLAN p. 11
5.9 Key Issue 9: Support of "unauthenticated" emergency session over Untrusted WLAN p. 12
5.9.1 Key Issue 9.1: Support of "unauthenticated" emergency session over ePDG p. 12
5.9.2 Key Issue 9.2: Support of "unauthenticated" emergency session over WLAN AN p. 12
5.10 Key Issue 10: Support for IMS based Non-Voice Emergency Services p. 12
5.11 Key Issue 11: Means by which the order in which an emergency session is attempted over the available networks p. 13
5.12 Key Issue 12: Handover Active Emergency call from WLAN to 3GPP p. 13
5.13 Key Issue 13: Handover Active Emergency call from 3GPP to WLAN p. 13
5.14 Key Issue 14: Determine if ePDG supports emergency service p. 14
5.15 Key Issue 15: Stay connected to an ePDG that supports emergency service p. 14
5.16 Key issue 16: Determine Emergency Call Numbers p. 14
5.17 Key issue 17: IMEI check p. 14
6 Solutions p. 15
6.1 Solution 1: ePDG selection when UE can detect being in the home country p. 15
6.2 Solution 2: ePDG selection when the UE cannot know it is in Home Country p. 15
6.3 Solution 3 for key issue #3: UPLI via SIP for untrusted WLAN p. 16
6.3.1 Overview p. 16
6.4 Solution 4 for key issue #3: UPLI via EPC for untrusted WLAN p. 16
6.4.1 Overview p. 16
6.5 Solution 5 for key issue #3: UPLI via IKEV2 for untrusted WLAN p. 16
6.6 Solution 6 for key issue #3: UPLI to OMA server p. 17
6.7 Solution 7 for key issue #3: UPLI to OMA server (fallback use case) p. 17
6.8 Solution 8: Location information from LRF for s2a p. 17
6.8.1 Solution principles p. 17
6.8.2 Reference architecture p. 18
6.8.3 LRF functionalities p. 18
6.8.4 HSS/AAA functionalities p. 18
6.8.5 PDN GW functionalities p. 18
6.8.6 PCRF functionalities p. 19
6.8.7 UE functionalities p. 19
6.8.8 User provided and network provided UE location via LRF p. 19
6.9 Solution 9: Handling of UE multiple provided location information p. 20
6.10 Solution 10: Location Information Included in SIP Register p. 20
6.10.1 Overview p. 20
6.11 Solution 11: Determine Emergency Call Numbers p. 21
6.11.1 Solution description p. 21
6.11.2 Retrieve the list of Emergency Call Numbers from a WLAN AP p. 21
6.12 Solution 12: Select a WLAN for Emergency Services p. 21
6.13 Solution 13: Determine Location & Country Info p. 22
6.14 Solution 14: Overall procedure p. 22
6.14.1 Network settings to support Emergency services over WLAN p. 22
6.14.2 Conditions for UE to set up an Emergency service over WLAN p. 22
6.14.3 Overview p. 22
6.14.4 EPC access for emergency services in S2b case p. 23
6.15 Solution 15: Authenticated UE leveraging indication of ePDG/TWAN support for emergency services p. 24
6.15.1 Overview p. 24
6.15.2 Way to provide the indication of emergency bearer support in case of Untrusted access p. 25
6.15.3 UE getting added IP Connectivity for emergency services over an ePDG p. 25
6.15.4 Way to provide the indication of emergency bearer support in case of trusted access p. 25
6.15.5 UE Request for PDN connectivity for emergency services in case of trusted access in MCM p. 26
6.16 Solution 16: Support of emergency services by TWAN p. 26
6.16.1 Overview p. 26
6.16.2 UE Attach to TWAN for emergency services (for emergency services that require authenticated UE) p. 26
6.17 Solution 17: Support of Mobility with 3GPP access (EPC). p. 28
6.17.1 Overview of the possible solutions p. 28
6.17.2 Solution based on retrieving PGW ID from LRF/GMLC p. 28
6.17.3 Solution based on HSS storing the PGW for emergency PDN connection p. 30
6.18 Solution 18 for Key issue 3: ePDG Push of location information to LRF/LS at emergency attachment/De-attachment p. 33
6.19 Solution 19: Support of emergency services for un-authenticated UE p. 34
6.19.1 Overview p. 34
6.19.2 Detailed solution for a TWAN access p. 36
6.19.2.1 Emergency session over TWAN for an UE with USIM but that but can't get authenticated (case 3) p. 36
6.19.2.2 Call flow for an emergency session over TWAN in SCM in case of an un-authenticated UE p. 36
6.19.2.3 Call flow for an emergency session over TWAN in MCM in case of an UE without USIM p. 39
6.19.2.4 Determination of the MSK in case of an un-authenticated UE p. 40
6.19.3 Detailed solution for Untrusted WLAN access p. 41
6.20 Solution 20: Support of emergency services for un-authenticated UE on S2b p. 43
6.21 Solution 21: Access Selection for Emergency Sessions p. 45
6.22 Solution 22: Local Emergency Numbers List over WLAN access p. 46
6.23 Solution 23 for Key issue 3: Using the emergency signalling channel for on-demand UE Location update mid-session. p. 46
6.24 Solution 24: ePDG selection for emergency bearer services p. 47
6.25 Solution 25 for Key issue 3: Network Initiated IKE-based WiFi Query for on-demand UE Location mid-emergency session. p. 50
6.26 Solution 26 for Key Issue 1: ePDG Selection for emergency services p. 51
6.27 Solution 27 for Key issue 3: NPLI for Untrusted WiFi emergency sessions p. 51
6.28 Solution 28: ePDG Selection for emergency services in phase 2 p. 52
6.29 Solution 29 for Key Issue 12: handover of an active emergency call from WLAN to 3GPP CS with E-STN-DR p. 56
6.29.1 Procedures p. 56
6.29.2 Impacts on existing nodes and functionality p. 57
6.29.3 Solution Evaluation p. 57
6.30 Solution 30 for Key issue 3: TWAG Push of location information to LRF/LS at emergency attachment/De-attachment p. 58
6.31 Solution 31: EIR check reusing the same Principle than in case of regular sessions p. 58
6.32 Solution 32: High level principles for emergency ePDG selection reusing the solution defined for regular ePDG selection p. 59
7 Overall evaluation p. 60
7.1 Overall evaluation for phase 1 (FS_SEW1) p. 60
7.2 Overall evaluation for phase 2 (FS_SEW2) p. 60
7.2.1 Evaluation on the solutions related with Determine Emergency Call Numbers p. 60
7.2.2 Evaluation on the solutions related with Support of Mobility with 3GPP access (EPC) p. 60
7.2.3 Evaluation on the solutions related with LRF p. 61
7.2.4 Evaluation on the solutions related with Handover of an active emergency call between WLAN and 3GPP CS p. 61
8 Conclusions p. 62
$ Change History p. 64
