Data forwarding method and system for vertical handover

A data forwarding method for a vertical handover of a user equipment, comprising:

• acquiring an address of a data forwarding unit located in a serving network and an address of a forwarding attachment unit located in a target network;
• transmitting information required for establishing an Internet Protocol (IP) tunnel with forwarding attachment unit to the data forwarding unit;
• and
• performing, when the vertical handover is initiated, an intra-network handover from a serving base station to the data forwarding unit.

A data forwarding apparatus located in a serving network for a vertical handover, comprising:

• a user equipment controller which acquires an address of a forwarding attachment unit located in a target network and a data forwarding preparation request from a user equipment;
• an Internet Protocol (IP) tunnel controller which establishes an IP tunnel with the forwarding attachment unit using the address acquired by the user equipment controller;
• and
• a data forwarding controller which forwards, when the vertical handover is initiated, handover packets buffered in a serving base station to the forwarding attachment unit through the IP tunnel.

A user equipment for a vertical handover from a serving network to a heterogeneous target network, comprising:

• a forward attachment function (FAF) acquisition unit for acquiring an address of a forward attachment unit located in the target network;
• a data forwarding function (DFF) acquisition unit for acquiring an address of a data forwarding unit located in the serving network;
• a DFF signaling controller for controlling transmission of information required for establishing an Internet Protocol (IP) tunnel between the data forwarding unit and the forward attachment unit to the data forwarding unit and controlling, when the vertical handover is initiated, an intra-network handover from a serving base station to the data forwarding unit;
• and
• an FAF signaling controller for controlling, after being connected to the target network, transmission of handover packets from the data forwarding unit to a target base station.