Carrier determination for a device

1. An apparatus comprising:

a processor that determines a first carrier of a plurality of carriers for a first device to transmit first hybrid automatic repeat request acknowledgement feedback information;

a transmitter that:

transmits, to the first device, first downlink control information indicating the first carrier, wherein the first downlink control information further indicates a set of physical resource blocks within the first carrier to the first device; and

transmits second downlink control information to a second device, wherein the second downlink control information indicates the first carrier and the set of physical resource blocks within the first carrier for the second device to transmit second hybrid automatic repeat request acknowledgement feedback information; and

a receiver that:

receives the first hybrid automatic repeat request acknowledgement feedback information from the first device on the first carrier using the set of physical resource blocks; and

receives the second hybrid automatic repeat request acknowledgement feedback information from the second device on the first carrier using the set of physical resource blocks.

2. The apparatus of claim 1 , wherein the first downlink control information further indicates an orthogonal cover sequence index to the first device.

3. The apparatus of claim 1 , wherein:

the processor determines a control channel for the first device, wherein the control channel is defined by at least one of the set of physical resource blocks and an orthogonal cover sequence index, and the first downlink control information indicates the control channel; and

the receiver receives the first hybrid automatic repeat request acknowledgement feedback information from the first device using the control channel.

4. The apparatus of claim 1 , wherein:

the processor determines a time for the first device to transmit the first hybrid automatic repeat request acknowledgement feedback information;

the transmitter transmits, to the first device, a first indicator indicating a first time offset between a downlink transmission for the first device and the determined time; and

the receiver receives the first hybrid automatic repeat request acknowledgement feedback information from the first device during the determined time.

5. The apparatus of claim 4 , wherein:

the transmitter transmits, to the second device, a second indicator indicating a second time offset between a downlink transmission for the second device and the determined time; and

the receiver receives the second hybrid automatic repeat request acknowledgement feedback information from the second device during the determined time.

6. The apparatus of claim 1 , wherein the first downlink control information indicates an offset between the end of a downlink transmission burst and the start of an uplink transmission burst.

7. The apparatus of claim 1 , wherein:

the processor determines a random backoff counter for the first device; and

the transmitter transmits, to the first device, a first indicator indicating the random backoff counter.

8. The apparatus of claim 7 , wherein the transmitter transmits, to a second device, a second indicator indicating the random backoff counter.

9. A method comprising:

determining a first carrier of a plurality of carriers for a first device to transmit first hybrid automatic repeat request acknowledgement feedback information;

transmitting, to the first device, first downlink control information indicating the first carrier, wherein the first downlink control information further indicates a set of physical resource blocks within the first carrier to the first device;

transmitting second downlink control information to a second device, wherein the second downlink control information indicates the first carrier and the set of physical resource blocks within the first carrier for the second device to transmit second hybrid automatic repeat request acknowledgement feedback information;

receiving the first hybrid automatic repeat request acknowledgement feedback information from the first device on the first carrier using the set of physical resource blocks; and

receiving the second hybrid automatic repeat request acknowledgement feedback information from the second device on the first carrier using the second set of physical resource blocks.

10. The method of claim 9 , wherein the first downlink control information further indicates an orthogonal cover sequence index to the first device.

11. The method of claim 9 , further comprising:

determining a control channel for the first device, wherein the control channel is defined by at least one of the set of physical resource blocks and an orthogonal cover sequence index, and the first downlink control information indicates the control channel; and

receiving the first hybrid automatic repeat request acknowledgement feedback information from the first device using the control channel.

12. The method of claim 9 , further comprising:

determining a time for the first device to transmit the first hybrid automatic repeat request acknowledgement feedback information;

transmitting, to the first device, a first indicator indicating a first time offset between a downlink transmission for the first device and the determined time; and

receiving the first hybrid automatic repeat request acknowledgement feedback information from the first device during the determined time.

13. The method of claim 12 , further comprising:

transmitting, to the second device, a second indicator indicating a second time offset between a downlink transmission for the second device and the determined time; and

receiving the second hybrid automatic repeat request acknowledgement feedback information from the second device during the determined time.

14. The method of claim 9 , wherein the first downlink control information indicates an offset between the end of a downlink transmission burst and the start of an uplink transmission burst.

15. The method of claim 9 , further comprising:

determining a random backoff counter for the first device; and

transmitting, to the first device, a first indicator indicating the random backoff counter.

16. The method of claim 15 , further comprising transmitting, to a second device, a second indicator indicating the random backoff counter.

17. An apparatus comprising:

a receiver that receives first downlink control information indicating:

a first carrier of a plurality of carriers for transmitting hybrid automatic repeat request acknowledgement feedback information; and

a control channel for transmitting the hybrid automatic repeat request acknowledgement feedback information, wherein the first downlink control information further indicates a set of physical resource blocks within the first carrier for transmitting the hybrid automatic repeat request acknowledgement feedback information, and the control channel is defined by at least one of the set of physical resource blocks and an orthogonal cover sequence index; and

a transmitter that transmits the hybrid automatic repeat request acknowledgement feedback information on control channel using the set of physical resource blocks.

18. The apparatus of claim 17 , wherein the first downlink control information further indicates an orthogonal cover sequence index for transmitting the hybrid automatic repeat request acknowledgement feedback information.

19. The apparatus of claim 17 , wherein:

the receiver receives a first indicator indicating a time offset between a downlink transmission and a time for transmitting the hybrid automatic repeat request acknowledgement feedback information; and

the transmitter transmits the hybrid automatic repeat request acknowledgement feedback information during the time.

20. The apparatus of claim 17 , wherein the first downlink control information indicates a time offset between the end of a downlink transmission burst and the start of an uplink transmission burst.

21. The apparatus of claim 17 , further comprising a processor, wherein:

the receiver receives a second indicator indicating a random backoff counter; and

the processor performs listen-before-talk using the random backoff counter on the first carrier.

22. A method comprising:

receiving first downlink control information indicating:

a first carrier of a plurality of carriers for transmitting hybrid automatic repeat request acknowledgement feedback information; and

a control channel for transmitting the hybrid automatic repeat request acknowledgement feedback information, wherein the first downlink control information further indicates a set of physical resource blocks within the first carrier for transmitting the hybrid automatic repeat request acknowledgement feedback information, and the control channel is defined by at least one of the set of physical resource blocks and an orthogonal cover sequence index; and

transmitting the hybrid automatic repeat request acknowledgement feedback information on the control channel using the set of physical resource blocks.

23. The method of claim 22 , wherein the first downlink control information further indicates an orthogonal cover sequence index for transmitting the hybrid automatic repeat request acknowledgement feedback information.

24. The method of claim 22 , further comprising:

receiving a first indicator indicating a time offset between a downlink transmission and a time for transmitting the hybrid automatic repeat request acknowledgement feedback information; and

transmitting the hybrid automatic repeat request acknowledgement feedback information during the time.

25. The method of claim 22 , wherein the first downlink control information indicates a time offset between the end of a downlink transmission burst and the start of an uplink transmission burst.

26. The method of claim 22 , further comprising:

receiving a second indicator indicating a random backoff counter; and

performing listen-before-talk using the random backoff counter on the first carrier.