1 Scope

22.2793GPPCombined Circuit Switched (CS) and IP Multimedia Subsystem (IMS) sessionsStage 1TS

The present document specifies service requirements for Combining CS and IMS services using a CS speech or CS multimedia call in association with an IMS session. The IMS session may consist of one or more IMS services.

Requirements for the following capabilities are included:

– Radio capability exchange.

– Terminal capability exchange.

– E.164 number exchange.

– Adding IMS session to an ongoing CS call.

– Adding a CS call to an ongoing IMS session.

– Supplementary services as they relate to CSICS.

It is intended that the capabilities defined herein for CSICS shall support interoperability between different operator networks, and roaming.