Method and apparatus for multicast transmission with separation of cp and up in a wireless communication system

A method performed by a Central Unit (CU)-Control Plane (CP) of a Radio Access Network (RAN) node in a wireless communication system, the method comprising,

• transmitting, to a CU-User Plane (UP) of the RAN node, a Bearer Context Setup Request message to request establishing resources for a Multicast and/or Broadcast Service (MBS),
• wherein the Bearer Context Setup Request message includes an identifier (ID) of the MBS;
• receiving, from the CU-UP, a Bearer Context Setup Response message in response to the Bearer Context Setup Request message;
• transmitting, to a Distributed Unit (DU) of the RAN node, a Context Setup Request message to request establishing a radio bearer for the MBS;
• and
• receiving, from the DU, a Context Setup Response message in response to the Context Setup Request message.

A Central Unit (CU)-Control Plane (CP) of a Radio Access Network (RAN) node in a wireless communication system comprising:

• a memory;
• and
• at least one processor operatively coupled to the memory, and configured to:
• transmit, to a CU-User Plane (UP) of the RAN node, a Bearer Context Setup Request message to request establishing resources for a Multicast and/or Broadcast Service (IBS),
• wherein the Bearer Context Setup Request message includes an identifier (ID) of the MBS;
• receive, from the CU-UP, a Bearer Context Setup Response message in response to the Bearer Context Setup Request message;
• transmit, to a Distributed Unit (DU) of the RAN node, a Context Setup Request message to request establishing a radio bearer for the MBS;
• and
• receive, from the DU, a Context Setup Response message in response to the Context Setup Request message.

A non-transitory computer-readable medium having stored thereon a plurality of instructions, which, when executed by a processor of a Central Unit (CU)-Control Plane (CP) of a Radio Access Network (RAN) node in a wireless communication system, cause the CU-CP of the RAN node to perform operations, wherein the operations comprises:

• transmitting, to a CU-User Plane (UP) of the RAN node, a Bearer Context Setup Request message to request establishing resources for a Multicast and/or Broadcast Service (MBS),
• wherein the Bearer Context Setup Request message includes an identifier (ID) of the MBS;
• receiving, from the CU-UP, a Bearer Context Setup Response message in response to the Bearer Context Setup Request message;
• transmitting, to a Distributed Unit (DU) of the RAN node, a Context Setup Request message to request establishing a radio bearer for the MBS;
• and
• receiving, from the DU, a Context Setup Response message in response to the Context Setup Request message.