Content for TR 23.749 Word version: 14.0.0
1 Scope p. 6
GSMA has identified a new roaming model for VoLTE called "S8 Home Routed (S8HR)" whereby the PGW, PCRF and P-CSCF are located in the HPLMN also when the UE is roaming in a VPLMN. S8HR roaming architecture aims to provide IMS services to UEs roaming in VPLMN with the UE to network IMS interface (Gm) between the UE and the HPLMN only and not requiring any IMS network to network interface (NNI) between the VPLMN and HPLMN.
The present document studies and evaluates the architecture enhancements required to support S8HR for VoLTE. The architecture enhancements should also be applicable to other IMS services.
The study will cover at a minimum the following topics:
- Support of Emergency calls to meet regulatory requirement
- Impacts on SRVCC for the S8HR roaming scenarios required by GSMA.
- Coexistence of LBO and S8HR roaming architectures
- Providing VPLMN Identity to IMS entities in HPLMN
- Handling of geo-local number
2 References p. 6
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.
[1]
TR 21.905: "Vocabulary for 3GPP Specifications".
[2] Void.
[3] Void.
[4]
GSMA PRD IR.92: "IMS Profile for Voice and SMS".
[5]
GSMA PRD IR.94: "IMS Profile for Conversational Video Service".
[6]
GSMA PRD IR.88: "LTE and EPC Roaming Guidelines".
[7]
TS 23.401: "General Packet Radio Service (GPRS) Enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access".
[8]
TS 23.228: "IP Multimedia Subsystem (IMS); Stage 2".
[9]
TS 23.167: "IP Multimedia Subsystem (IMS) emergency sessions".
[10]
TS 24.229: "IP Multimedia Call Control based on SIP and SDP; Stage 3 ".
[11]
TS 23.203: "Policy and Charging Control architecture".
[12]
TS 33.203: "Access Security for IP-based services".
[13]
TS 22.278: "Service requirement for the Evolved Packet System (EPS)".
3 Definitions, symbols and abbreviations p. 7
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
3.1 Definitions p. 7
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.
VoLTE:
Voice over LTE is a profile for voice over IMS over LTE, and for SMS over IMS and SMS over SGs as defined in GSMA PRD IR.92 [4].
3.2 Symbols p. 7
For the purposes of the present document, the following symbols apply:
VoLTE
Voice over LTE
S8HR
S8 Home Routed
3.3 Abbreviations p. 7
