Apparatus and method for controlling data flow in wireless communication system

A method performed by a secondary node (SN) for dual connectivity in a wireless communication system, the method comprising:

• receiving, from a master node (MN), an addition request message associated with at least one quality of service (QoS) flow of a protocol data unit (PDU) session for offloading the at least one QoS flow of the PDU session;
• transmitting, to the MN, an addition request acknowledge message, in response to the addition request message;
• and
• receiving, from the MN, a radio resource control (RRC) reconfiguration complete message,
• wherein the MN is configured with a first layer for mapping between a QoS flow and a data radio bearer (DRB),
• wherein the SN is configured with a second layer for mapping between a QoS flow and a DRB, and
• wherein the first layer and the second layer are configured for the PDU session for the offloading of the at least one QoS flow of the PDU session between the MN and the SN.

A core network entity, comprising:

• at least one transceiver;
• and
• at least one processor coupled to the at least one transceiver and configured to:
• receive, from a master node (MN), a session modification message for offloading at least one quality of service (QoS) flow of a protocol data unit (PDU) session from the MN to a secondary node (SN), wherein the PDU session comprises a plurality of QoS flows of the PDU session, and
• transmit, to the MN, a response message,
• wherein the session modification message includes information of the at least one QoS flow,
• wherein the MN is configured with a first layer for mapping between a QoS flow and a data radio bearer (DRB),
• wherein the SN is configured with a second layer for mapping between a QoS flow and a DRB, and
• wherein the first layer and the second layer are configured for the PDU session for the offloading of the at least one QoS flow of the PDU session between the MN and the SN.

A secondary node (SN) for dual connectivity in a wireless communication system, the SN comprising:

• at least one transceiver;
• and
• at least one processor operably coupled to the at least one transceiver and configured to:
• receive, from a master node (MN), an addition request message associated with at least one quality of service (QoS) flow of a protocol data unit (PDU) session for offloading the at least one QoS flow of the PDU session,
• transmit, to the MN, an addition request acknowledge message, in response to the addition request message, and
• receive, from the MN, a radio resource control (RRC) reconfiguration complete message,
• wherein the MN is configured with a first layer, for mapping between a QoS flow and a data radio bearer (DRB),
• wherein the SN is configured with a second layer for mapping between a QoS flow and a DRB, and
• wherein the first layer and the second layer are configured for the PDU session for the offloading of the at least one QoS flow of the PDU session between the MN and the SN.