Method for operating failure timer during conditional handover in wireless communication system

A method performed by a serving cell in a wireless communication system, the method comprising:

• transmitting, to a target cell, a handover request message;
• receiving, from the target cell, a handover request acknowledge(ACK) message;
• and
• transmitting, to a user equipment (UE), configuration information for a conditional handover to the target cell,
• wherein whether at least one of conditions included in the configuration information for the conditional handover is satisfied is determined, and
• wherein the conditional handover to the target cell is performed, and a timer included in the configuration information is started in case that at least one of the conditions included in the configuration information for the conditional handover is satisfied.

A user equipment (UE) comprising:

• a transceiver configured to transmit or receive at least one signal;
• and
• a controller coupled to the transceiver,
• wherein the controller is configured to:
• receive, from a serving cell, configuration information for a conditional handover to a target cell;
• determine whether at least one of conditions included in the configuration information for the conditional handover is satisfied;
• and
• perform the conditional handover to the target cell and start a timer included in the configuration information, in case that at least one of the conditions included in the configuration information for the conditional handover is satisfied.

A base station comprising:

• a transceiver configured to transmit or receive at least one signal;
• and
• a controller coupled to the transceiver,
• wherein the controller is configured to:
• transmit, to a target cell, a handover request message;
• receive, from the target cell, a handover request acknowledge(ACK) message;
• and
• transmit, to a user equipment (UE), configuration information for a conditional handover to the target cell,
• wherein whether at least one of conditions included in the configuration information for the conditional handover is satisfied is determined, and
• wherein the conditional handover to the target cell is performed and a timer included in the configuration information is started in case that at least one of the conditions included in the configuration information for the conditional handover is satisfied.