Method for supporting handover and corresponding apparatus

A method performed by A user plane function (UPF) for supporting an inter-system handover from an evolved packet system (EPS) system to a 5th generation (5G) system, the method comprising:

• receiving, from a session management function (SMF), a message including first tunnel information for data forwarding between a serving gateway (SGW) and the UPF, and second tunnel information for downlink data forwarding between a base station and the UPF allocated by the base station;
• receiving, from the SGW, a data packet through a tunnel for data forwarding based on the first tunnel information;
• and
• forwarding, to the base station, the data packet in a protocol data unit (PDU) session tunnel.

An access and mobility management function (AMF) for supporting an inter-system handover from an evolved packet system (EPS) system to a 5th generation (5G) system, the AMF comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• receive, from a session management function (SMF), a first message including quality of service (Qos) flow information;
• transmit, to a base station, a handover request message including E-UTRAN radio access bearer (E-RAB) information and the Qos flow information;
• receive, from the base station, a handover request acknowledgement message including information indicating whether a data forwarding for at least one Qos flow associated with a protocol data unit (PDU) session is accepted or not, the information being determined based on the E-RAB information and the QoS flow information, when the PDU session is accepted by the base station;
• and
• transmit, to the SMF, a second message including tunnel information for the data forwarding.

A user plane function (UPF) for supporting an inter-system handover from an evolved packet system (EPS) system to a 5th generation (5G) system, the UPF comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• receive, from a session management function (SMF), a message including first tunnel information for data forwarding between a serving gateway (SGW) and the UPF and second tunnel information for downlink data forwarding between a base station and the UPF allocated by the base station;
• receive, from the SGW, a data packet through a tunnel for data forwarding based on the first tunnel information;
• and
• forward, to the base station, the data packet in a protocol data unit (PDU) session tunnel.