Abstract: A method for handling a call using Sessions Initiation Protocol (SIP) includes sending an INVITE or a first media type by a network side to user equipment, sending an UPDATE of a second media type by the user equipment to the network side, receiving an SIP global failure response for the UPDATE by the user equipment from the network side, sending an SIP success response for the INVITE of the first media type by the user equipment to the network side, receiving an ACK of the first media type by the user equipment from the network side, and establishing a call session of the first media type between the user equipment and the network side.

Abstract: A voice call management method is provided. The voice call management method may be applied to an apparatus. The voice call management method may include the following steps. The apparatus may determine the current scenario associated with the operation environment of the apparatus. Then, the apparatus may determine to perform a voice call through a modem (MD) voice engine or through an application processor (AP) voice engine according to the current scenario.

Abstract: A method to manage call continuity in a network environment including a circuit-switched network and an IP multimedia subsystem (IMS) network is provided. A UE monitors one or more ongoing sessions in an IMS network, and the ongoing sessions contain at least one conference call. The UE detects a network-switching event for the UE to switch from the IMS network to a circuit-switched CS network. The UE then determines the one or more ongoing sessions within the IMS network to be released or transferred to the CS network. Finally, the UE performs a session transfer procedure for transferring the determined sessions.

Abstract: A method to manage call continuity in a network environment including a circuit-switched network and an IP multimedia subsystem (IMS) network is provided. A UE monitors one or more ongoing sessions in an IMS network, and the ongoing sessions contain at least one conference call. The UE detects a network-switching event for the UE to switch from the IMS network to a circuit-switched CS network. The UE then determines the one or more ongoing sessions within the IMS network to be released or transferred to the CS network. Finally, the UE performs a session transfer procedure for transferring the determined sessions.

Abstract: A method to manage call continuity in a network environment including a circuit-switched network and an IP multimedia subsystem (IMS) network is provided. A UE monitors one or more ongoing sessions in an IMS network, and the ongoing sessions contain at least one conference call. The UE detects a network-switching event for the UE to switch from the IMS network to a circuit-switched CS network. The UE then determines the one or more ongoing sessions within the IMS network to be released or transferred to the CS network. Finally, the UE performs a session transfer procedure for transferring the determined sessions.

Abstract: A method to manage call continuity in a network environment including a circuit-switched network and an IP multimedia subsystem (IMS) network is provided. A UE monitors one or more ongoing sessions in an IMS network, and the ongoing sessions contain at least one conference call. The UE detects a network-switching event for the UE to switch from the IMS network to a circuit-switched CS network. The UE then determines the one or more ongoing sessions within the IMS network to be released or transferred to the CS network. Finally, the UE performs a session transfer procedure for transferring the determined sessions.

Abstract: A proxy server including a system manager and a database is provided. The system manager includes an internal registrar module, an external registrar module, a session manager module and a signal routing module. The internal registrar module provides an internal register service for a plurality of nodes in a first service network. The external registrar module registers at an internet service provider providing network services in a second service network. The session manager module manages session processes in the first service network and the second service network and manages the network services shared between the registered nodes. The signal routing module routes control signals of the session processes between the first service network and the second service network. The database stores information related to the registered nodes.

Abstract: A proxy server including a system manager and a database is provided. The system manager includes an internal registrar module, an external registrar module, a session manager module and a signal routing module. The internal registrar module provides an internal register service for a plurality of nodes in a first service network. The external registrar module registers at an internet service provider providing network services in a second service network. The session manager module manages session processes in the first service network and the second service network and manages the network services shared between the registered nodes. The signal routing module routes control signals of the session processes between the first service network and the second service network. The database stores information related to the registered nodes.