Method and apparatus for supporting l1/l2-based mobility in cu-du split in a wireless network system

A Distributed Unit (DU) of a gNB, comprising:

• a transceiver;
• a memory;
• and
• at least one processor operatively coupled to the memory and the transceiver, and adapted to:
• receive, from a Central Unit (CU) of the gNB, a radio resource control (RRC) reconfiguration;
• forward, to a User Equipment (UE), the RRC reconfiguration;
• receive, from the UE, an RRC reconfiguration complete;
• forward, to the CU of the gNB, the RRC reconfiguration complete;
• receive, from a UE, a Layer 1 (L1) measurement report;
• transmit, to a CU of the gNB, a UE Context Modification Required message including information on at least one candidate target cell;
• receive, from the CU of the gNB, a UE Context Modification Confirm message include information on a target cell among the at least one candidate target cell;
• and
• transmit, to the UE, a cell switching command including information on the target cell.

A wireless device, comprising:

• a transceiver;
• a memory;
• and
• a processor operatively coupled to the transceiver and the memory, and adapted to:
• receive, from a Central Unit (CU) of the gNB through a Distributed Unit (DU) of the gNB, a radio resource control (RRC) reconfiguration;
• transmit, to the CU of the gNB through the DU of the gNB, an RRC reconfiguration complete;
• transmit, to the DU of the gNB, a Layer 1 (L1) measurement report,
• wherein the DU of the gNB transmits, to a CU of the gNB, a UE Context Modification Required message including information on at least one candidate target cell, and
• wherein the DU of the gNB receives, from the CU of the gNB, a UE Context Modification Confirm message include information on a target cell among the at least one candidate target cell;
• and
• receive, from the DU of the gNB, a cell switching command including information on the target cell.