Device and method for call forwarding based on IMS

A call forwarding device based on an Internet Protocol (IP) multimedia subsystem (IMS), comprising:

• a terminal;
• and
• an IMS communication system connected to the terminal;
• wherein the IMS communication system is respectively connected to an IMS special service number device, an IMS user database and an IMS maintenance device;
• the terminal communicates with the IMS communication system through a wired network or a wireless network;
• after the terminal establishes a communication with the IMS special service number device, a forwarding condition and a forwarding number set through an IVR, and a calling number and a called number of the terminal are saved in the IMS user database;
• the IMS communication system allocates Session Initiation Protocol (SIP) accounts for the terminal, and a communication is established among the SIP accounts;
• wherein the SIP accounts comprise a calling number and a called number of the terminal, and a forwarding number set by the called number;
• when the calling number of the terminal dials the called number, the communication system of the IMS detects a status of the called number, and a communication is established between the calling number and the forwarding number of the terminal according to the forwarding condition set by the called number;
• wherein the communication comprises a voice communication, a video communication and a message communication, so that the video communication and the message communication are forwarded together with the voice communication;
• the terminal comprises an Internet Protocol (IP) videophone, an electronic device installed with an SIP client, and an Integrated Access Device (IAD) adaptable to a digital phone;
• and the IP videophone, the electronic device and the IAD are connected to the IMS communication system through the wired network;
• and
• the terminal further comprises a Voice over Long-Term Evolution (VoLTE)/Voice over New Radio (VoNR) mobile terminal and an electronic device installed with the SIP client;
• and the VoLTE/VoNR mobile terminal and the electronic device are connected to the IMS communication system through the wireless network,
• wherein when the wired network fails, the IMS communication system detects that the called number is offline, and the call forwarding is activated, the calling number of the terminal establishes the communication with the forwarding number, and when the wired network is restored, the offline call forwarding is automatically disabled.