Method and apparatus for selecting carrier

1. A method for transmitting, by a user equipment (UE), a medium access control protocol data unit (MAC PDU) in a wireless communication system, the method comprising:

allocating resource grants on multiple carriers;

selecting a first carrier among the multiple carriers, based on allocation times of the resource grants;

allocating a resource of the selected first carrier to a logical channel with the highest priority;

selecting a second carrier among the multiple carriers, based on the allocation times of the resource grants, based on remaining data for the logical channel and a resource grant on the selected first carrier being exhausted; and

transmitting the MAC PDU, based on the resource of the selected first carrier.

2. The method of claim 1 , wherein the first carrier is a carrier which has the earliest resource grant among the multiple carriers.

3. The method of claim 2 , wherein, based on a plurality of carriers having the earliest resource grant, the first carrier is a carrier which has the lowest channel busy ratio (CBR) value among the plurality of carriers.

4. The method of claim 1 , wherein the first carrier is a carrier which has a resource grant within a time offset among the multiple carriers.

5. The method of claim 4 , wherein, based on a plurality of carriers having the resource grant within the time offset, the first carrier is a carrier which has the lowest channel busy ratio (CBR) value among the plurality of carriers.

6. The method of claim 4 , wherein the time offset starts from a time of the earliest resource grant among the multiple carriers.

7. The method of claim 1 , further comprising:

constructing the MAC PDU, based on a data of the logical channel with the highest priority.

8. The method of claim 1 , further comprising:

selecting a destination, having the logical channel with the highest priority, among logical channels having data available for transmission.

9. The method of claim 8 , wherein the resource of the selected first carrier is allocated to the logical channel with the highest priority, among the logical channels belonging to the selected destination and having data available for transmission.

10. The method of claim 1 , wherein the second carrier is a carrier which has the second earliest resource grant among the multiple carriers.

11. The method of claim 1 , wherein the second carrier is a carrier which has a resource grant within a time offset among the multiple carriers.

12. The method of claim 1 , the resource grants are allocated on the multiple carriers, by the UE, autonomously.

13. The method of claim 1 , the resource grants are allocated on the multiple carriers, by the UE, based on a configuration received from a base station.

14. The method of claim 1 , wherein the UE communicates with at least one of a mobile terminal, a network or autonomous vehicles other than the UE.

15. A user equipment (UE) configured to transmit a medium access control protocol data unit (MAC PDU) in a wireless communication, the UE comprising:

at least one transceiver;

at least one processor; and

at least one memory storing instructions that, based on being executed by the at least one processor, control the UE to perform operations comprising:

allocating resource grants on multiple carriers;

selecting a first carrier among the multiple carriers, based on allocation times of the resource grants;

allocating a resource of the selected first carrier to a logical channel with the highest priority;

selecting a second carrier among the multiple carriers, based on the allocation times of the resource grants, based on remaining data for the logical channel and a resource grant on the selected first carrier being exhausted; and

transmitting, via the transceiver, the MAC PDU, based on the resource of the selected first carrier.