Voice Call Continuity (VCC) between Circuit Switched (CS) and IP Multimedia Subsystem (IMS); Stage 2
The present document specifies the functional architecture and information flows of the Voice Call Continuity feature which provides the capability to transfer the path of an existing voice call between a 3GPP CS system (GSM/UMTS) and IMS, and vice versa. These capabilities were designed per requirements in TS 22.101 [20].