Method and apparatus for performing inter-menb handover without senb change in wireless communication system

A method performed by a target master node (MN) in an inter-MN handover procedure, the method comprising:

• receiving a handover request message from a source MN, wherein the handover request message includes an identifier (ID) of a secondary node (SN);
• transmitting a SN addition request message to the SN, wherein the SN addition request message includes an ID of a user equipment (UE), wherein the ID of the UE was allocated by the SN;
• receiving a SN addition request acknowledge message from the SN as a response to the SN addition request message;
• transmitting a handover request acknowledge message to the source MN as a response to the handover request message, wherein the handover request acknowledge message includes information indicating that the SN is kept in the inter-MN handover procedure,
• wherein the UE is currently connected to both the source MN and the SN in dual connectivity.

A target master node (MN) in an inter-MN handover procedure, the target MN comprising:

• a memory;
• a transceiver;
• and
• a processor, operably coupled to the memory and the transceiver, that:
• controls the transceiver to receive a handover request message from a source MN, wherein the handover request message includes an identifier (ID) of a secondary node (SN);
• controls the transceiver to transmit a SN addition request message to the SN, wherein the SN addition request message includes an ID of a user equipment (UE), wherein the ID of the UE was allocated by the SN,
• controls the transceiver to receive a SN addition request acknowledge message from the SN as a response to the SN addition request message;
• controls the transceiver to transmit a handover request acknowledge message to the source MN as a response to the handover request message, wherein the handover request acknowledge message includes information indicating that the SN is kept in the inter-MN handover procedure,
• wherein the UE is currently connected to both the source MN and the SN in dual connectivity.