4.7 Voice Call Continuity for cdma2000 1x (saes-vcc_1x) uid_360020

Resources: S2

References

Document	Title/Contents
WID(s)
SP-080132	WID on 3GPP System Architecture Evolution Specification (SAES) - covers S1,S2,S3
Impacted Specifications
TS	?
New Dedicated Specifications/Reports
TS	?

4.8 Sae impacts on ims (saes-sa_ims) uid_350031

Resources: S2

References

Document	Title/Contents
WID(s)
SP-080132	WID on 3GPP System Architecture Evolution Specification (SAES) - covers S1,S2,S3
Impacted Specifications
TS	?
New Dedicated Specifications/Reports
TS	?

4.9 Cs Fallback in eps (saes-csfb) uid_390036

Resources: S2,C1,C4

References

Document	Title/Contents
WID(s)
SP-080097	S2 WID on CS Fallback in EPS
CP-080791	C1 WID on Stage 3 for CS Fallback in EPS
Impacted Specifications
CT1	TS 24.007, 24.008, 24.011, 29.018
CT4	TS 23.007, 23.008
New Dedicated Specifications/Reports
TS 23.272	Circuit Switched (CS) fallback in Evolved Packet System (EPS); Stage 2 - S2
TS 23.401	General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access - S2
TS 24.301	Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3 -C1
TS 29.118	Mobility Management Entity (MME) - Visitor Location Register (VLR) SGs interface specification - C1
TR 24.801	3GPP System Architecture Evolution (SAE); CT WG1 aspects
TS 29.274	3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3 - C4
TS 29.277	Optimized Handover Procedures and Protocols between EUTRAN Access and 1xRTT Access - C4

UID	Name	Resource	Hyperlink	TS_TR
390036	CS Fallback in EPS	-	SP-080097	-
400001	Stage 2 for CS Fallback in EPS	S2	SP-080097	new (23.272, 23.401)
400102	Stage 3 for CS Fallback in EPS	C1	CP-080791	24.007, 24.008, 24.011, 29.018, new (24.301, 24.801, 29.118)
400003	Stage 3 for CS Fallback in EPS	C4	CP-080791	23.007, 23.008, 29.274, new 29.277

In order to guarantee support of legacy CS services such as voice for UEs camped on E-UTRAN, mobile operators are expected to deploy IMS. Many operators however will continue to have access to already deployed 2G/3G CS network for foreseeable future which can also be used as a fallback. Such CS fallback can help to:

• provide smooth transition to LTE by better utilising an already deployed CS infrastructure for voice services with UE with LTE and 2G/3G capability.

• decouple the deployment of IMS from the deployment of the Evolved Packet System for other operators who choose not to use LTE for legacy CS services at all but instead use UE with LTE and 2G/3G capability for delivery of CS services such as voice over 2G/3G CS domain,

In order to achieve these goals a mechanism is required to inform UE with LTE and 2G/3G capability of incoming/outgoing CS calls and thus may trigger the reselection of a suitable CS domain access (either 2G or 3G).

This work specifies the architecture enhancements for functionality to enable Fallback from E-UTRAN access to 2G/3G CS domain access. Using this functionality, voice and other CS-domain services (e.g. CS UDI video / SMS/ LCS / USSD) are realized by reuse of CS infrastructure. It documents overall CS Fallback architecture and stage 2 level specifications for the 3GPP components. Roaming aspects were documented as well.

CT1 and CT4 specified Stage3 capabilities and functionalities according to SA2 Stage 2 in TS 23.272 as follows:

• combined EPS/IMSI attach and tracking area update procedures based on similar mechanisms as those used by the combined GPRS attach and routing area update procedures from 3GPP TS 24.008, in order to register the UE to the CS domain for future Fallback from E-UTRAN access to 2G/3G CS domain access;

• IMSI or combined EPS/IMSI detach procedure, both UE and network initiated, based on similar mechanisms as those used by the GPRS detach procedure from 3GPP TS 24.008;

• CS fallback related capability for the UE to receive the CS paging request via EPS and respond to this paging via the GERAN/UTRAN, or to request a CS call in E-UTRAN and establish the call in GERAN/UTRAN;

• procedures for supporting Mobile originating and Mobile terminating SMS in EPS;

• procedures required for the support of CS fallback to 1xRTT;

• procedures on the SGs interface between the MME and the MSC, based on the Gs interface procedures.