Method and apparatus for improving acknowledgement/negative acknowledgement feedback

1. A method for wireless communication comprising:

receiving a downlink grant for scheduling data transmissions, wherein the downlink grant includes a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe;

determining whether the TPC command is an acknowledgement/negative acknowledgement (ACK/NACK) resource indicator for an uplink control channel resource based on a value of the DAI, wherein the determining comprises:

using the TPC command for power control for a communication on the uplink subframe when the DAI is equal to one, and

reinterpreting the TPC command as the ACK/NACK resource indicator when the DAI is greater than one; and

transmitting, during the uplink subframe, one or more ACK/NACK feedback elements using the uplink control channel resource when the DAI is greater than one.

2. The method of claim 1 , wherein the determining further comprises:

receiving the TPC command where the DAI is greater than one.

3. The method of claim 2 , wherein the receiving further comprises receiving a second downlink grant including a second TPC command and a second DAI, where the second DAI is greater than one;

wherein the determining further comprises determining that the second TPC command has a same value as the TPC command, and

wherein the reinterpreting further comprises reinterpreting both the TPC command and the second TPC command as the ACK/NACK resource indicator.

4. The method of claim 1 , wherein the TPC command is determined to be the ACK/NACK resource indicator, the ACK/NACK resource indicator indicating the uplink control channel resource from a plurality of higher layer configured control channel resources; or an offset, relative to a higher layer configured control channel resource, which specifies the control channel resource for use as the uplink control channel resource.

5. The method of claim 4 , wherein the higher layer configured control channel resources are configured using radio resource control (RRC) signaling.

6. The method of claim 1 , wherein the method is performed as part of a time division duplex (TDD) operation.

7. The method of claim 1 , wherein the uplink control channel resource is associated with an uplink control channel, and wherein the uplink control channel is a physical uplink control channel (PUCCH).

8. The method of claim 7 , wherein the resource is formatted with PUCCH format 3.

9. The method of claim 1 , wherein the uplink control channel resource includes ACK/NACK information for each of one or more downlink subframes associated with the uplink subframe.

10. The method of claim 1 , wherein the method is performed as part of a single carrier operation.

11. The method of claim 1 , wherein the method is performed as part of a multi-carrier operation including a primary carrier and one or more secondary carriers, wherein the uplink control channel resource is transmitted on the uplink subframe of the primary carrier and provides ACK/NACK feedback for one or more downlink subframes associated with the primary carrier and the one or more secondary carriers.

12. A method of wireless communications, comprising:

transmitting a downlink grant for scheduling data transmissions, wherein the downlink grant includes a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe, wherein the TPC command provides power control for a communication on the uplink subframe when the DAI is equal to one, and wherein the TPC command is replaced with an acknowledgement/negative acknowledgement (ACK/NACK) resource indicator when the DAI is greater than one; and

receiving a signal including uplink control channel information, where ACK/NACK feedback for one or more downlink subframes associated with the uplink subframe are included in an uplink control channel resource indicated by the ACK/NACK resource indicator when the DAI is greater than one.

13. The method of claim 12 , further comprising:

determining that an uplink-downlink configuration results in greater than a threshold number of downlink subframes ACK/NACK feedback elements.

14. The method of claim 13 , wherein the threshold is 4 ACK/NACK responses.

15. The method of claim 12 , wherein the uplink control channel resource is associated with an uplink control channel, and wherein the uplink control channel is a physical uplink control channel (PUCCH) and wherein the uplink control channel resource is formatted as PUCCH format 3.

16. The method of claim 12 , wherein the ACK/NACK resource indicator indicates:

the uplink control channel resource from a plurality of higher layer configured control channel resources; or

an offset, relative to a higher layer configured control channel resource, which specifies the control channel resource for use as the uplink control channel resource.

17. The method of claim 16 , wherein the high layer configured control channel resources are configured using radio resource control (RRC) signaling.

18. The method of claim 12 , wherein the method is performed as part of a time division duplex (TDD) operation.

19. The method of claim 12 , wherein the method is performed as part of a single carrier operation.

20. The method of claim 12 , wherein the method is performed as part of a multi-carrier operation including a primary carrier and one or more secondary carriers, wherein the uplink control channel resource is transmitted on the uplink subframe of the primary carrier and provides ACK/NACK feedback for one or more downlink subframes associated with the primary carrier and the one or more secondary carriers.

21. An apparatus for wireless communication, comprising:

means for receiving a downlink grant for scheduling data transmissions, wherein the downlink grant includes a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe;

means for determining whether the TPC command is an acknowledgement/negative acknowledgement (ACK/NACK) resource indicator for an uplink control channel resource based on a value of the DAI, wherein the means for determining is configured to:

use the TPC command for power control for a communication on the uplink subframe when the DAI is equal to one, and

reinterpret the TPC command as the ACK/NACK resource indicator when the DAI is greater than one; and

means for transmitting, during the uplink subframe, one or more ACK/NACK feedback elements using the uplink control channel resource when the DAI is greater than one.

22. The apparatus of claim 21 , wherein the means for determining further comprises:

means for receiving the TPC command where the DAI is greater than one.

23. The apparatus of claim 22 , wherein the means for receiving further comprises means for receiving a second downlink grant including a second TPC command and a second DAI, where the second DAI is greater than one;

wherein the means for determining further comprises means for determining that the second TPC command has a same value as the TPC command; and

wherein the means for reinterpreting further comprises means for reinterpreting both the TPC command and the second TPC command as the ACK/NACK resource indicator.

24. An apparatus of wireless communications, comprising:

means for transmitting a downlink grant for scheduling data transmissions, wherein the downlink grant includes a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe, wherein the TPC command provides power control for a communication on the uplink subframe when the DAI is equal to one, and wherein the TPC command is replaced with an acknowledgement/negative acknowledgement (ACK/NACK) resource indicator when the DAI is greater than one; and

means for receiving a signal including uplink control channel information, where ACK/NACK feedback for one or more downlink subframes associated with the uplink subframe are included in an uplink control channel resource indicated by the ACK/NACK resource indicator when the DAI is greater than one.

25. The apparatus of claim 24 , further comprising:

means for determining that an uplink-downlink configuration results in greater than a threshold number of downlink subframes ACK/NACK feedback elements.

26. The apparatus of claim 25 , wherein the threshold is 4 ACK/NACK responses.

27. A computer program product, comprising:

a non-transitory computer-readable medium comprising code for:

receiving a downlink grant for scheduling data transmissions, wherein the downlink grant includes a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe;

determining whether the TPC command is an acknowledgement/negative acknowledgement (ACK/NACK) resource indicator for an uplink control channel resource based on a value of the DAI, wherein the determining comprises:

using the TPC command for power control for a communication on the uplink subframe when the DAI is equal to one, and

reinterpreting the TPC command as the ACK/NACK resource indicator when the DAI is greater than one; and

transmitting, during the uplink subframe, one or more ACK/NACK feedback elements using the uplink control channel resource when the DAI is greater than one.

28. The computer program product of claim 27 , wherein the non-transitory computer-readable medium further comprises code for:

receiving the TPC command where the DAI is greater than one.

29. A computer program product, comprising:

a non-transitory computer-readable medium comprising code for:

transmitting a downlink grant for scheduling data transmissions, wherein the downlink grant includes a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe, wherein the TPC command provides power control for a communication on the uplink subframe when the DAI is equal to one, and wherein the TPC command is replaced with an acknowledgement/negative acknowledgement (ACK/NACK) resource indicator when the DAI is greater than one; and

receiving a signal including uplink control channel information, where ACK/NACK feedback for one or more downlink subframes associated with the uplink subframe are included in an uplink control channel resource indicated by the ACK/NACK resource indicator when the DAI is greater than one.

30. The computer program product of claim 29 , wherein the non-transitory computer-readable medium further comprises code for:

determining that an uplink-downlink configuration results in greater than a threshold number of downlink subframes ACK/NACK feedback elements.

31. An apparatus for wireless communication, comprising:

a processing system configured to:

receive a downlink grant for scheduling data transmissions, wherein the downlink grant includes a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe;

determine whether the TPC command is an acknowledgement/negative acknowledgement (ACK/NACK) resource indicator for an uplink control channel resource based on a value of the DAI, wherein the processing system is configured to determine by:

using the TPC command for power control for a communication on the uplink subframe when the DAI is equal to one, and

reinterpreting the TPC command as the ACK/NACK resource indicator when the DAI is greater than one; and

transmit, during the uplink subframe, one or more ACK/NACK feedback elements using the uplink control channel resource when the DAI is greater than one.

32. The apparatus of claim 31 , wherein the processing system is further configured to:

receive the TPC command where the DAI is greater than one.

33. The apparatus of claim 32 , wherein the processing system is further configured to:

receive a second downlink grant including a second TPC command and a second DAI, where the second DAI is greater than one;

determine that the second TPC command has a same value as the TPC command; and

reinterpret both the TPC command and the second TPC command as the ACK/NACK resource indicator.

34. The apparatus of claim 31 , wherein the TPC command is determined to be the ACK/NACK resource indicator, the ACK/NACK resource indicator indicating the uplink control channel resource from a plurality of higher layer configured control channel resources; or an offset, relative to a higher layer configured control channel resource, which specifies the control channel resource for use as the uplink control channel resource.

35. An apparatus for wireless communication, comprising:

a processing system configured to:

transmit a downlink grant for scheduling data transmissions, wherein the downlink grant includes a transmission power control (TPC) command and a downlink assignment index (DAI) for an uplink subframe, wherein the TPC command provides power control for a communication on the uplink subframe when the DAI is equal to one, and wherein the TPC command is replaced with an acknowledgement/negative acknowledgement (ACK/NACK) resource indicator when the DAI is greater than one; and

receive a signal including uplink control channel information, where ACK/NACK feedback for one or more downlink subframes associated with the uplink subframe are included in an uplink control channel resource indicated by the ACK/NACK resource indicator when the DAI is greater than one.

36. The apparatus of claim 35 , wherein the processing system is further configured to:

determine that an uplink-downlink configuration results in greater than a threshold number of downlink subframes ACK/NACK feedback elements.