Patent ID: 8908634

Claim:
A method for controlling a voice call continuity (VCC) function by a terminal, the method comprising: receiving, by a terminal, a feature tag indicating whether or not a VCC application server (VCC AS) currently supports a VCC function, wherein the feature tag is transmitted from the VCC AS when an operator policy related to the VCC function is changed; enabling or disabling, by the terminal, a corresponding VCC functionality of the terminal based on the received feature tag, wherein the corresponding VCC functionality of the terminal is enabled if the feature tag indicates the VCC AS currently supports the VCC function, and the corresponding VCC functionality of the terminal is disabled if the feature tag indicates the VCC AS currently does not support the VCC function; determining, by the terminal, a domain for transmitting VCC enabling information which indicates whether the corresponding VCC functionality of the terminal is enabled or disabled, between a circuit switching (CS) domain an IP multimedia subsystem (IMS) domain; transmitting a call setup message from the terminal to a mobile switching center, the call setup message including the VCC enabling information which indicates whether the VCC functionality of the terminal is enabled or disabled; transmitting an initial address message (IAM) message including the VCC enabling information from the mobile switching center to a media gateway controller; transmitting an invite message including the VCC enabling information from the media gateway controller to the VCC AS through an IMS core; and selectively performing, by the VCC AS, an anchoring operation in response to the invite message based on the VCC enabling information included in the invite message, wherein the CS domain is selected for transmitting the VCC enabling information when the feature tag indicates the VCC AS currently does not support the VCC function; wherein the VCC enabling information is transmitted, by the terminal, via the determined domain, wherein an outgoing call or session from the terminal is not anchored by the VCC AS, when the VCC enabling information indicates that the corresponding VCC functionality of the terminal is disabled, and wherein a domain transfer is not performed when the outgoing call or session is not anchored by the VCC AS.