Method and apparatus for performing data transmission under processing enhanced handover in wireless communication system

A user equipment (UE) in a wireless communication system, the UE comprising:

• at least one transceiver;
• at least one processor;
• and
• at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising:
• transmitting an uplink (UL) data to a first node based on a first Quality of Service (QoS) flow to data radio bearer (DRB) mapping rule;
• receiving, from the first node, a handover command including information related to a second QoS flow to DRB mapping rule;
• transmitting the UL data to the first node based on the first QoS flow to DRB mapping rule, until an UL data path is switched from the first node to the second node;
• and
• transmitting the UL data to the second node based on the second QoS flow to DRB mapping rule, after the UL data path is switched from the first node to the second node.

An apparatus for a user equipment (UE), the apparatus comprising:

• at least one processor;
• and
• at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising:
• transmitting an uplink (UL) data to a first node based on a first Quality of Service (QoS) flow to data radio bearer (DRB) mapping rule;
• receiving, from the first node, a handover command including information related to a second QoS flow to DRB mapping rule;
• transmitting the UL data to the first node based on the first QoS flow to DRB mapping rule, until an UL data path is switched from the first node to the second node;
• and
• transmitting the UL data to the second node based on the second QoS flow to DRB mapping rule, after the UL data path is switched from the first node to the second node.

A computer readable storage medium storing at least one computer program comprising instructions that, when executed by at least one processor, cause the at least one processor to perform operations for a user equipment (UE), the operations comprising:

• transmitting an uplink (UL) data to a first node based on a first Quality of Service (QoS) flow to data radio bearer (DRB) mapping rule;
• receiving, from the first node, a handover command including information related to a second QoS flow to DRB mapping rule;
• transmitting the UL data to the first node based on the first QoS flow to DRB mapping rule, until an UL data path is switched from the first node to the second node;
• and
• transmitting the UL data to the second node based on the second QoS flow to DRB mapping rule, after the UL data path is switched from the first node to the second node.

A method for transmitting an uplink (UL) data by a user equipment (UE) in a wireless communication system, the method comprising:

• transmitting the UL data to a first node based on a first Quality of Service (QoS) flow to data radio bearer (DRB) mapping rule;
• receiving, from the first node, a handover command including information related to a second QoS flow to DRB mapping rule;
• transmitting the UL data to the first node or a second node based on the first QoS flow to DRB mapping rule until receiving an indication for applying the second QoS flow to DRB mapping rule;
• and
• transmitting the UL data to the first node or the second node based on the second QoS flow to DRB mapping rule, after receiving the indication for applying the second QoS flow to DRB mapping rule.