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Content for
TR 23.885
Word version: 11.0.0
1…
5…
5
Architecture model and reference points
6
Solutions
7
Assessment of the solutions
8
Conclusion
A
Mechanisms to re-enable E-UTRAN capability
B
Mechanisms for GERAN/UTRAN sending Handover/Relocation Required message
$
Change history
5
Architecture model and reference points
5.1
General
5.2
Reference architecture
Word‑p. 11
5.2.1
3GPP UTRAN/GERAN and E-UTRAN SRVCC architecture
5.2.2
3GPP UTRAN/GERAN and UTRAN (HSPA) SRVCC architecture
5.3
Functional Entities
Word‑p. 12
5.3.1
MSC Server enhanced for SRVCC
5.4
Reference points
6
Solutions
6.1
Solution 1: Session transfer initiated on E-UTRAN/HSPA
6.1.1
Functional Description
6.1.2
Information flows
Word‑p. 13
6.1.2.1
GERAN/UTRAN Attach procedure
6.1.2.2
E-UTRAN attach procedure
6.1.2.3
Call establishment procedure in GERAN/UTRAN
6.1.2.4
SRVCC from E-UTRAN/HSPA to GERAN/UTRAN
Word‑p. 14
6.1.2.5
Handover procedure in GERAN/UTRAN
6.1.2.6
Call flows for SRVCC from UTRAN/GERAN to E-UTRAN
6.1.2.6.1
SRVCC handover from GERAN without DTM support to E-UTRAN
6.1.2.6.2
SRVCC handover from UTRAN or GERAN with PS handover support to E-UTRAN
Word‑p. 16
6.1.2.7
Call flows for SRVCC from UTRAN/GERAN to HSPA
Word‑p. 18
6.1.2.7.1
SRVCC handover from GERAN without DTM support to HSPA
6.1.2.7.2
SRVCC handover from UTRAN or GERAN with PS handover support to HSPA
Word‑p. 19
6.2
Solution 2: Session transfer initiated on E-UTRAN/HSPA
Word‑p. 20
6.2.0
General
6.2.1
Functional Description
Word‑p. 21
6.2.2
Information flows
6.2.2.1
GERAN/UTRAN Attach procedure
6.2.2.2
E-UTRAN attach procedure
6.2.2.3
Call establishment procedure in GERAN/UTRAN
6.2.2.4
SRVCC from E-UTRAN/HSPA to GERAN/UTRAN
Word‑p. 22
6.2.2.5
Handover procedure in GERAN/UTRAN
6.2.2.6
Call flows for SRVCC from UTRAN/GERAN to E-UTRAN
Word‑p. 23
6.2.2.6.1
SRVCC handover from GERAN without DTM support to E-UTRAN
6.2.2.6.2
SRVCC handover from UTRAN or GERAN with PS handover support to E-UTRAN
Word‑p. 24
6.3
Solution 3+5: Media anchoring in serving network with Access Transfer Control Functionality
Word‑p. 25
6.3.1
Architecture Reference Model
6.3.2
Functional Entities
Word‑p. 26
6.3.2.1
ATCF
6.3.2.2
SCC AS
Word‑p. 27
6.3.2.3
P-CSCF
6.3.2.4
MSC Server enhanced for reverse SRVCC
6.3.2.5
SGSN enhanced for rSRVCC
6.3.2.6
UE enhanced for rSRVCC
6.3.2.7
HSS
Word‑p. 28
6.3.2.8
MME/SGSN enhanced for rSRVCC
6.3.3
Message Flows
6.3.3.1
General principles
6.3.3.2
GERAN/UTRAN Attach procedure
Word‑p. 29
6.3.3.3
E-UTRAN attach procedure
6.3.3.3a
Informing the source RAN about the possibility to perform rSRVCC
6.3.3.4
Codec and transport address related procedure
Word‑p. 30
6.3.3.4.1
General
6.3.3.4.2
Information in IMS registration and handover procedure
6.3.3.5
Establish a session over CS
6.3.3.5.1
STN-SR allocated by the ATCF and Transfer Info sent to ATCF
6.3.3.5.2
Registration when ATCF involved
Word‑p. 31
6.3.3.5.3
Origination procedures when ATCF involved
6.3.3.5.4
Termination procedures when ATCF involved
Word‑p. 32
6.3.3.6
CS - PS Access Transfer Overview
Word‑p. 33
6.3.3.6.1
Anchored in ATGW
6.3.3.6.2
Not Anchored in ATGW
Word‑p. 34
6.3.3.7
Access Transfer Preparation
6.3.3.7.1
Access Transfer Preparation Alternative 1
6.3.3.7.2
Access Transfer Preparation Alternative 2
Word‑p. 36
6.3.3.7.3
Access Transfer Preparation Alternative 3
Word‑p. 38
6.3.3.7.4
Access Transfer Preparation Alternative 4
Word‑p. 40
6.3.3.7.5
Access Transfer Preparation Alternative 5 (the combination)
Word‑p. 43
6.3.3.8
IMS Session Continuity procedure
Word‑p. 45
6.3.3.8.0
General
6.3.3.8.1
Anchored in ATGW
Word‑p. 46
6.3.3.8.2
Not Anchored in ATGW
Word‑p. 47
6.3.3.9
Identification of serving PS node
Word‑p. 48
6.3.3.9.1
Alternative 1: CN nodes based
6.3.3.9.2
Alternative 2: UE and/or RAN provided information
6.3.3.9.3
Alternative 3: RAN provided information
Word‑p. 49
6.3.4
IMS registration Considerations
Word‑p. 50
6.3.4.1
General
6.3.4.2
ATCF controlled registration
6.3.4.3
SCC AS controlled registration
Word‑p. 51
6.3.4.4
rSRVCC HO Cancellation in case of UE loss of IMS registration
Word‑p. 52
6.4
Solution 4: Session transfer by local anchoring with Indirect Forwarding
Word‑p. 53
6.4.1
Functional Description
6.4.2
Architecture Reference Model
Word‑p. 54
6.4.3
Information flows
6.4.3.1
Initial ATTACH / TA update procedure
6.4.3.2
Call origination procedure in GERAN/UTRAN
6.4.3.3
Call termination procedure in GERAN/UTRAN
Word‑p. 56
6.4.3.4
SRVCC handover from UTRAN or GERAN to LTE
Word‑p. 57
6.5
Solution 5: IMS procedure is initiated by MSC Server to ATCF
Word‑p. 59
6.5.1
Architecture Reference Model
6.5.1.1
General
6.5.1.2
Concepts of reverse SRVCC
Word‑p. 60
6.5.2
Functional Entities
Word‑p. 61
6.5.2.1
ATCF
6.5.2.2
SCC AS
6.5.2.3
S-CSCF
Word‑p. 62
6.5.2.4
MSC Server enhanced for reverse SRVCC
6.5.2.5
MME
6.5.2.6
UE enhanced for reverse SRVCC
6.5.2.7
UTRAN/GERAN
6.5.3
Message Flows
Word‑p. 63
6.5.3.1
Home control rSRVCC
6.5.3.2
RAU/LAU/TAU procedure
6.5.3.3
GERAN/UTRAN performs handover procedure
6.5.3.4
Maintaining IMS Registration
6.5.3.5
Preparation of media transfer
6.5.3.6
Selection of the ATCF
Word‑p. 64
6.5.3.7
Originating sessions in CS
Word‑p. 65
6.5.3.7.1
Serving MSC Server is not enhanced for ICS
6.5.3.7.2
Serving MSC Server is enhanced for ICS
Word‑p. 66
6.5.3.7.3
Serving MSC Server is enhanced for rSRVCC
6.5.3.7.4
UE is enhanced for ICS
Word‑p. 67
6.5.3.8
Terminating sessions in CS
Word‑p. 68
6.5.3.8.1
UE is not enhanced for ICS
6.5.3.8.2
UE is enhanced for ICS
Word‑p. 69
6.5.3.9
CS - PS Access Transfer
Word‑p. 70
6.5.3.9.0
Introduction
6.5.3.9.1
IMS Session Continuity procedure
6.5.3.9.2
CS to PS handover procedure
Word‑p. 71
6.5.3.10
Failure to complete CS-PS Access Transfer
Word‑p. 72
7
Assessment of the solutions
Word‑p. 73
7.1
Assessment Criteria
7.2
Assessment of the solution 3+5 access transfer preparation alternatives
Word‑p. 74
8
Conclusion
Word‑p. 77
8.1
General
8.2
Access Transfer preparation / How to reserve bearer for VoIP
8.3
Source SGSN selection by MSC Server
8.4
Maintaining IMS registration over PS access during the CS session
8.5
Summary
A
Mechanisms to re-enable E-UTRAN capability
Word‑p. 78
A.1
Functional description
A.2
Information flows
Word‑p. 79
A.2.1
Proposed signalling flow for Alternative A to re-enable E-UTRAN capabilities using broadcast indicator
A.2.2
Proposed signalling flow for Alternative B to re-enable E-UTRAN capabilities using NAS indicator
Word‑p. 80
A.2.3
Proposed signalling flow for Alternative C to re-enable E-UTRAN capabilities using change in RFSP/RAC of the UE
Word‑p. 81
B
Mechanisms for GERAN/UTRAN sending Handover/Relocation Required message
Word‑p. 82
$
Change history
Word‑p. 83