Method and apparatus for conditional handover based on the service time of candidate cells in a wireless communication system

1. A method performed by a wireless device in a wireless communication system, the method comprising,

receiving, from a network, handover configuration including information related to candidate cells to be measured and service time of each of the candidate cells;

performing measurement on the candidate cells;

selecting a cell among the candidate cells based on the service time of each of the candidate cells; and

performing handover to the selected cell,

wherein the cell is selected among the candidate cells based on remaining time of the service time of each of the candidate cells from a specific time point, and

wherein the measurement on the candidate cells is performed at the specific time point.

2. The method of claim 1 , wherein the candidate cells includes a non-terrestrial networks (NTN) cell.

3. The method of claim 1 , wherein the method further comprises,

determining whether each of the candidate cells meets a handover condition based on the measurement, wherein the handover configuration includes information on the handover condition.

4. The method of claim 3 , wherein the cell is selected among the candidate cells which meet the handover condition.

5. The method of claim 3 , wherein the each of the candidate cells is determined to meet the handover condition based on that cell quality of the each of the candidate cells being equal to or higher than a cell quality threshold.

6. The method of claim 3 , wherein the each of the candidate cells is determined to meet the handover condition based on that the service time of each of the candidate cells being equal to or higher than a minimum time threshold.

7. The method of claim 3 , wherein the each of the candidate cells is determined to be met the handover condition based on that the service time of each of the candidate cells being lower than a maximum time threshold.

8. The method of claim 1 , wherein the wireless device is in communication with at least one of a user equipment, a network, or an autonomous vehicle other than the wireless device.

9. A wireless device configured to operate in a wireless communication system, the wireless device comprising:

a transceiver;

a memory; and

at least one processor operatively coupled to the transceiver and the memory, and configured to:

control the transceiver to receive, from a network, handover configuration including information related to candidate cells to be measured and service time of each of the candidate cells,

perform handover to the selected cell,

wherein the cell is selected among the candidate cells based on remaining time of the service time of each of the candidate cells from a specific time point, and

wherein the measurement on the candidate cells is performed at the specific time point.

10. The wireless device of claim 9 , wherein the at least one processor is further configured to,

determine whether each of the candidate cells is met meets a handover condition, wherein the handover configuration includes information on the handover condition.

11. The wireless device of claim 10 , wherein the cell is selected among the candidate cells which meet the handover condition.

12. A non-transitory computer-readable medium having stored thereon a plurality of instructions, which, when executed by a processor of a wireless device, cause the wireless device to:

receive, from a network, handover configuration including information related to candidate cells to be measured and service time of each of the candidate cells;

perform measurement on the candidate cells;

select a cell among the candidate cells based on the service time of each of the candidate cells; and

perform handover to the selected cell,

wherein the cell is selected among the candidate cells based on remaining time of the service time of each of the candidate cells from a specific time point; and

wherein the measurement on the candidate cells is performed at the specific time point.