Method and apparatus for a remote user equipment (UE) to support direct to indirect communication path switching in a wireless communication system

A remote UE (User Equipment), comprising:

• a control circuit;
• a processor installed in the control circuit;
• and
• a memory installed in the control circuit and operatively coupled to the processor;
• wherein the processor is configured to execute a program code stored in the memory to:
• establish a Radio Resource Control (RRC) connection with a network node;
• transmit a Layer 2 Identity (L2ID) of the remote UE to the network node;
• receive a first RRC Reconfiguration message from the network node for path switching from direct to indirect communication, wherein the first RRC Reconfiguration message includes a L2ID of a relay UE for the path switching;
• establish a PC5 connection with the relay UE;
• and
• transmit a first RRC Reconfiguration Complete message corresponding to the first RRC Reconfiguration message to the network node via the relay UE after establishing the PC5 connection with the relay UE,
• wherein the first RRC Reconfiguration Complete message forwarded from the relay UE to the network node is included in an adaptation layer Protocol Data Unit (PDU) and a local UE Identity (ID) for the remote UE is included in a header of the adaptation layer PDU.

A method for a network node, comprising:

• the network node establishes a Radio Resource Control (RRC) connection with a remote User Equipment (UE);
• the network node receives a Layer 2 Identity (L2ID) of the remote UE from the remote UE;
• the network node transmits a first RRC Reconfiguration message to the remote UE for path switching the remote UE from direct to indirect communication, wherein the first RRC Reconfiguration message includes a L2ID of a relay UE for the path switching;
• and
• the network node receives a first RRC Reconfiguration Complete message corresponding to the first RRC Reconfiguration message from the remote UE via the relay UE,
• wherein the first RRC Reconfiguration Complete message forwarded from the relay UE to the network node is included in an adaptation layer Protocol Data Unit (PDU) and a local UE Identity (ID) for the remote UE is included in a header of the adaptation layer PDU.