2009年12月27日

Service Continuity (1) - VCC, SCC, ICS, MMSC, SRVCC Overview

Service Continuity (1) - VCC, SCC, ICS, MMSC, SRVCC Overview











Alternatives for Delivering Voice in FTTP

Alternatives for Delivering Voice in FTTP

1). Service / Call / Session Continuity Overview


§ VCC - Voice Call Continuity

§ SCC - Service Centralization and Continuity

§ ICS - IMS Centralized Services

§ MMSC - MultiMedia Session Continuity

§ SRVCC - Single Radio Voice Call Continuity


2). VCC OV - Voice Call Continuity


§ The VCC function provides PS-CS Mobility for Voice functions.

§ The 3GPP Release 7 Voice Call Continuity also supports an optimized approach to VCC that reduces idle time during Inter-technology handoff (between WiFi and GSM).

§ The previous Voice Call Continuity (VCC) specification which requires the handover decision to be made by the mobile (device-centric Voice Call Continuity (VCC))


3). SCC OV - Service Centralization and Continuity


§ The VCC function provides PS-CS Mobility for Voice functions.

§ The VCC AS capability will evolve into the SCC AS capability to additionally support CS-PS and PS-PS functionality with service continuity across the transfers.

§ The 3GPP Release 8 IMS Service Centralization and Continuity (SCC) AS encompasses IMS Centralized Services (ICS) functions and IMS Service Continuity (SC) functions.

§ IMS service continuity (SC) is coupled with IMS Centralized Services (ICS) so that all session signaling is controlled in IMS whatever the type of access used by the terminal (i.e. CS or PS).


4). ICS OV - IMS Centralized Services


§ While in Release 7, the hot application specifications for IMS services were Multi Media Telephony (MMTel) and device-centric VCC

§ IMS multimedia telephony service is the main interest to ICS. ICS also supports IMS service continuity

§ The work in 3GPP Release 8 seems to have to have shifted towards IMS Centralized Services (ICS) and a network-centric Voice Call Continuity.

§ IMS Centralized Services is an approach to the provision of communication services wherein services and service control are based on IMS mechanisms and enablers.

§ ICS is provided for a diversity of access networks (including circuit switched and IP based, wireless and wireline). Service continuity between domains (CS, PS) is also provided.

§ ICS allow mobile operators to connect and deliver IMS services to any device by connecting the IMS core to 2G, 3G, UMA Macro, Pico and Femto cells.

§ ICS as an enabler for wireless-wireline convergence (like FMC). With ICS, the user services are provided by IMS. ICS users are IMS subscribers. User sessions are controlled in IMS via PS or CS access.

§ Services supported by ICS should include at least: IMS supplementary services defined within 3GPP 24.173 and Other IMS hosted services

§ The ICS is an interim solution for a transition period when VoIP is not generally available due to lack of VoIP capable radio accesses (e.g. LTE, HSPA).


5). MMSC OV - MultiMedia Session Continuity


§ The combination of IMS centralized services (ICS) with IMS-based service continuity (SCC) have been standardized as multimedia session continuity (MMSC) in 3GPP Rel 8.


The following potential MMSC enhancements to IMS specifications that can improve the multimedia session continuity experience

§ Identification of session continuity scenarios;

§ PS-PS session continuity;

§ PS-PS session continuity in conjunction with PS-CS continuity;

§ Session continuity between 3GPP and non-3GPP systems;

§ Network-initiated Multimedia Session Transfer;

§ Mobility of media components of a session between different terminals under the control of the same user;

§ Coexistence and/or potential interactions with possible underlying mobility solutions defined by 3GPP. The solutions developed within this study should not have any impacts to underlying mobility solutions.

§ Session continuity between terminals in IMS service continuity solution will encompass the following capabilities - have been postponed to release 9:

- transfer/retrieve some or all media components

- add/remove media components of an ongoing multimedia session between different UEs.


6). SRVCC OV - Single Radio Voice Call Continuity


§ From network centric Single Radio Voice Call Continuity (SR VCC) approach is a major step towards solving the LTE voice gap.

§ Single Radio Voice Call Continuity (SRVCC) is used for Circuit Switched (CS) calls that are anchored in the IMS

- from E‑UTRAN to CDMA2000 1xCS

- from E‑UTRAN to UTRAN/GERAN

- from HSPA to UTRAN/GERAN

§ SRVCC from E‑UTRAN/UTRAN (HSPA) access to 3GPP UTRAN/GERAN CS accesses for voice calls that are anchored in the IMS

§ Handling of SRVCC from 3GPP UTRAN/GERAN CS accesses to E‑UTRAN/UTRAN (HSPA) direction is not specified in this release (R8)

§ A 3GPP SRVCC UE is a UE enhanced for IMS Service Continuity with the additional UE capabilities described in this specification for SRVCC between two access networks as above.

§ SRVCC (as Voice call continuity) between IMS over PS access and CS access for calls is anchored in IMS when the UE is capable of transmitting/receiving on only one of those access networks at a given time.


7). 3GPP Standards for related Service / Call Continuity


7-1). For VCC:

§ TS23.206 - Voice Call Continuity (VCC) between CS and IMS; Stage 2

§ TS23.507 - TISPAN; VCC; Stage 2 [TS23.206 Release 7, modified]

§ TS23.806 - Voice call continuity between CS) and IMS Study

§ TS23.826 - Feasibility study on VCC support for Emergency Calls

§ TS24.206 - Voice call continuity between CS and IMS; Stage 3


7-2). For Service Continuity (SCC):

§ TS23.237 - IMS Service Continuity

§ TS23.838 - IMS Service Continuity enhancements; Service, policy and interactions

§ TS24.237 - IP Multimedia Subsystem (IMS) Service Continuity; Stage 3

§ TS22.937 - Requirements for Service Continuity between mobile and WLAN networks


7-3). For ICS:

§ TS22.892 - Study on IMS Centralized Services (ICS) requirements

§ TS23.292 - IMS Centralized Services

§ TS23.883 - IMS Centralized Services study - Phase 2

§ TS23.892 - IP Multimedia Subsystem (IMS) centralized services

§ TS24.292 - IP Multimedia Core Network subsystem Centralized Services; Stage 3


7-4). For MMSC:

§ TS23.893 - Feasibility study on multimedia session continuity (MMSC); Stage 2


7-5). For SRVCC:

§ TS23.216 - Single Radio Voice Call Continuity

§ TS23.870 - SR VCC support for IMS Emergency Calls

§ TS29.820 - EPS; 3GPP Sv interface (MME to MSC, and SGSN to MSC) for SRVCC






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