Downlink control information (DCI) design for multi-component carrier scheduling

1. A method of wireless communication performed by a user equipment, the method comprising:

receiving a downlink control information (DCI) message having a DCI format, the DCI message scheduling a downlink data communication over a single component carrier or multiple component carriers, wherein the DCI message includes a first hybrid automatic repeat request (HARQ) process ID associated with a first component carrier and a second HARQ process ID associated with a second component carrier, the second HARQ process ID different from the first HARQ process ID;

determining, based on the received DCI message, whether the downlink data communication is scheduled over the single component carrier or the multiple component carriers;

receiving, based on the determining, the downlink data communication over the single component carrier or the multiple component carriers; and

transmitting, based on at least one of the first HARQ process ID or the second HARQ process ID, a HARQ feedback for the downlink data communication received over the single component carrier or the multiple component carriers.

2. The method of claim 1 , wherein the determining whether the downlink data communication is scheduled over the single component carrier or the multiple component carriers includes:

determining whether the DCI message has a first format associated with the single component carrier or a second format associated with the multiple component carriers.

3. The method of claim 1 , wherein the determining whether the downlink data communication is scheduled on the single component carrier or the multiple component carriers includes:

determining whether the received DCI message was received in a first search space associated with the single component carrier or a second search space associated with the multiple component carriers.

4. The method of claim 3 , wherein the receiving the DCI message includes receiving the DCI message in the first search space associated with the single component carrier.

5. The method of claim 3 , wherein the receiving the DCI message includes receiving the DCI message in the second search space associated with the multiple component carriers.

6. The method of claim 1 , wherein the determining whether the downlink data communication is scheduled over the single component carrier or the multiple component carriers includes:

determining whether at least one field of the DCI message indicates the downlink data communication is scheduled over the single component carrier or the multiple component carriers.

7. The method of claim 6 , wherein the at least one field includes a first field associated with the first component carrier and a second field associated with the second component carrier.

8. The method of claim 7 , wherein the determining whether the downlink data communication is scheduled over the single component carrier or the multiple component carriers includes:

determining the downlink data communication is scheduled over the single component carrier based on at least one of the first field or the second field having a value that is not assigned for a primary purpose of the respective field.

9. The method of claim 8 , wherein the value is not assigned for a frequency domain resource allocation (FDRA).

10. The method of claim 8 , wherein the determining whether the downlink data communication is scheduled over the single component carrier or the multiple component carriers includes:

determining the downlink data communication is scheduled over the multiple component carriers based on the first field and the second field having values that are assigned for the respective primary purpose of the first and second fields.

11. The method of claim 1 , wherein the downlink data communication scheduled by the DCI message includes a first retransmission associated with the first HARQ process ID and a second retransmission associated with the second HARQ process ID.

12. The method of claim 1 , wherein the DCI message includes a third HARQ process ID associated with the first component carrier and the second component carrier.

13. The method of claim 1 , wherein:

the receiving the DCI message includes receiving the DCI message over a physical downlink control channel (PDCCH) of a secondary cell; and

the receiving the downlink data communication includes receiving at least a first part of the downlink data communication over a physical downlink shared channel (PDSCH) of a primary cell.

14. The method of claim 13 , wherein the receiving the downlink data communication further includes:

receiving at least a second part of the downlink data communication over a PDSCH of the secondary cell.

15. A user equipment, comprising:

a transceiver configured to receive a downlink control information (DCI) message having a DCI format, the DCI message scheduling a downlink data communication over a single component carrier or multiple component carriers, wherein the DCI message includes a first hybrid automatic repeat request (HARQ) process ID associated with a first component carrier and a second HARQ process ID associated with a second component carrier, the second HARQ process ID different from the first HARQ process ID;

a processor in communication with the transceiver, the processor configured to determine, based on the received DCI message, whether the downlink data communication is scheduled over the single component carrier or the multiple component carriers,

wherein the transceiver is further configured to:

receive, based on the determination of the processor, the downlink data communication over the single component carrier or the multiple component carriers; and

transmit, based on at least one of the first HARQ process ID or the second HARQ process ID, a HARQ feedback for the downlink data communication received over the single component carrier or the multiple component carriers.

16. The user equipment of claim 15 , wherein the processor is further configured to:

determine whether the DCI message has a first format associated with the single component carrier or a second format associated with the multiple component carriers.

17. The user equipment of claim 15 , wherein the processor is further configured to:

determine whether the received DCI message was received in a first search space associated with the single component carrier or a second search space associated with the multiple component carriers.

18. The user equipment of claim 15 , wherein the processor is further configured to:

determine whether at least one field of the DCI message indicates the downlink data communication is scheduled over the single component carrier or the multiple component carriers.

19. The user equipment of claim 18 , wherein the at least one field includes a first field associated with the first component carrier and a second field associated with the second component carrier.

20. The user equipment of claim 19 , wherein the processor is further configured to:

determine the downlink data communication is scheduled over the single component carrier based on at least one of the first field or the second field having a value that is not assigned for a primary purpose of the respective field.

21. The user equipment of claim 20 , wherein the value is not assigned for a frequency domain resource allocation (FDRA).

22. The user equipment of claim 20 , wherein the processor is further configured to:

determine the downlink data communication is scheduled over the multiple component carriers based on the first field and the second field having values that are assigned for the respective primary purpose of the first and second fields.

23. The user equipment of claim 15 , wherein the processor is further configured to:

determine the downlink data communication scheduled by the DCI message includes a first retransmission associated with the first HARQ process ID and a second retransmission associated with the second HARQ process ID.

24. The user equipment of claim 15 , wherein the transceiver is further configured to receive the DCI message including a third HARQ process ID associated with the first component carrier and the second component carrier.

25. The user equipment of claim 15 , wherein the transceiver is further configured to:

receive the DCI message over a physical downlink control channel (PDCCH) of a secondary cell; and

receive at least a first part of the downlink data communication over a physical downlink shared channel (PDSCH) of a primary cell.

26. The user equipment of claim 25 , wherein the transceiver is further configured to:

receive at least a second part of the downlink data communication over a PDSCH of the secondary cell.

27. A user equipment, comprising:

means for receiving a downlink control information (DCI) message having a DCI format, the DCI message scheduling a downlink data communication over a single component carrier or multiple component carriers, wherein the DCI message includes a first hybrid automatic repeat request (HARQ) process ID associated with a first component carrier and a second HARQ process ID associated with a second component carrier, the second HARQ process ID different from the first HARQ process ID;

means for determining, based on the received DCI message, whether the downlink data communication is scheduled over the single component carrier or the multiple component carriers;

means for receiving, based on the determining, the downlink data communication over the single component carrier or the multiple component carriers; and

means for transmitting, based on at least one of the first HARQ process ID or the second HARQ process ID, a HARQ feedback for the downlink data communication received over the single component carrier or the multiple component carriers.

28. A non-transitory computer-readable medium having program code recorded thereon for wireless communication by a user equipment, the program code comprising:

code for causing the user equipment to receive a downlink control information (DCI) message having a DCI format, the DCI message scheduling a downlink data communication over a single component carrier or multiple component carriers, wherein the DCI message includes a first hybrid automatic repeat request (HARQ) process ID associated with a first component carrier and a second HARQ process ID associated with a second component carrier, the second HARQ process ID different from the first HARQ process ID;

code for causing the user equipment to determine, based on the received DCI message, whether the downlink data communication is scheduled over the single component carrier or the multiple component carriers;

code for causing the user equipment to receive, based on the determining, the downlink data communication over the single component carrier or the multiple component carriers; and

code for causing the user equipment to transmit, based on at least one of the first HARQ process ID or the second HARQ process ID, a HARQ feedback for the downlink data communication received over the single component carrier or the multiple component carriers.