The present document studies the mechanisms needed to support IMS Emergency sessions over WLAN (both in the Trusted -S2a - and in the untrusted -S2b- cases)
The study is split up into 2 phases corresponding to 2 SID (FS_SEW1 and FS_SEW2).
Topics to be studied in phase 1 (FS_SEW1) are:
Providing access to EPC over WLAN in order to support an emergency session only in case of "Valid" UEs as in the case 1 in clause 18.104.22.168 of TS 23.401: the support of emergency session is only studied for UEs which (a) have valid credentials to access EPC over WLAN and (b) are authorized to connect to EPC over WLAN in the location where they initiate an emergency session.
Providing Location information (in particular for untrusted WLAN). Only existing location determination mechanisms are considered i.e. location determination mechanisms that should not require standard effort. No location accuracy requirements are considered in phase 1.
Phase 1(FS_SEW1) will not consider solutions that imply specification activities in other SDO(s).
Topics to be studied in phase 2 (FS_SEW2) correspond to all the features not covered by phase 1, e.g.:
Support of other cases for the access to EPC over WLAN (e.g. the UE is authenticated but is in a location where it is restricted from regular service, or is unauthenticated or has no USIM).
Roaming cases (user not in his / her home country).
Support of session continuity of emergency sessions at inter-access mobility.
The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
: "Vocabulary for 3GPP Specifications".
: "Service aspects; Service principles".
: "General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access".
: " IP Multimedia Subsystem (IMS) emergency sessions".
IEEE Std 802.11-2012: "IEEE Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications".
WiFi Alliance Technical Committee, Hotspot 2.0 Technical Task Group: "Hotspot 2.0 (Release 2) Technical Specification", ver.5.00.
: "Architecture enhancements for non-3GPP accesses".
: "IP Multimedia Subsystem (IMS) Service Continuity; Stage 2".
: "Functional stage 2 description of Location Services (LCS)".
"Private Header (P-Header) Extensions to the Session Initiation Protocol (SIP) for the 3GPP".
: "Numbering, addressing and identification".
: "IP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3".
: "Location Services (LCS); Evolved Packet Core (EPC) LCS Protocol (ELP) between the Gateway Mobile Location Centre (GMLC) and the Mobile Management Entity (MME); SLg interface".
: "3GPP System Architecture Evolution (SAE); Security aspects of non-3GPP accesses e".
For the purposes of the present document, the terms and definitions given in TR 21.905
and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905
Emergency Session Transfer Number for DRVCC:
A number used by the UE to request the EATF AS to perform Session Transfer from PS to CS access. The E-STN-DR is dynamically assigned by EATF during IMS emergency session procedure with WLAN.
For the purposes of the present document, the abbreviations given in TR 21.905
and the following apply.
An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905
Emergency Session Transfer Number for DRVCC