Uplink feedback methods for operating with a large number of carriers
A method and apparatus for uplink feedback for operating with a large number of carriers are disclosed herein. A method in a wireless transmit/receive unit (WTRU) includes receiving a plurality of transport blocks over a set of a plurality of configured carriers, generating hybrid automatic repeat request (HARQ)-acknowledgment (ACK) feedback for the transport blocks and determining a number of HARQ-ACK feedback bits to use for the HARQ-ACK feedback. Further, the WTRU may apply, to the HARQ-ACK feedback bits, Reed-Muller coding on a condition that the number of HARQ-ACK feedback bits is less than or equal to a threshold or convolutional coding on a condition that the number of HARQ-ACK feedback bits is greater than a threshold. The WTRU may then transmit the encoded HARQ-ACK feedback bits. In addition, the WTRU may conditionally append cyclic redundancy check (CRC) bits onto the HARQ-ACK feedback bits, and encode and transmit the CRC bits.
1. A method, for uplink feedback for operating with a plurality of carriers, in a wireless transmit/receive unit (WTRU), the method comprising:
receiving, by the WTRU, a plurality of transport blocks over a plurality of configured carriers;
generating, by the WTRU, hybrid automatic repeat request (HARQ) acknowledgment (ACK) feedback for the plurality of transport blocks and channel state information (CSI) feedback for at least one of the plurality of configured carriers;
generating, by the WTRU, a feedback message that includes a number of HARQ-ACK feedback bits for the HARQ-ACK feedback and a number of CSI feedback bits for the CSI feedback;
determining, by the WTRU, a Physical Uplink Control Channel (PUCCH) format based on the number of HARQ-ACK feedback bits and the number of CSI feedback bits; and
transmitting, by the WTRU, the feedback message using the determined PUCCH format.
2. The method of claim 1 , wherein determining a PUCCH format comprises:
selecting, by the WTRU, a first PUCCH format or a second PUCCH format on a condition that the number of HARQ-ACK feedback bits is greater than zero and the number of CSI feedback bits is greater than zero;
wherein selecting a first PUCCH format or a second PUCCH format comprises:
selecting, by the WTRU, the first PUCCH format on a condition that a sum of the number of HARQ-ACK feedback bits and the number of CSI feedback bits is greater than a first threshold; and
selecting, by the WTRU, the second PUCCH format on a condition that a sum of the number of HARQ-ACK feedback bits and the number of CSI feedback bits is less than or equal to the first threshold.
3. The method of claim 1 , further comprising:
selecting, by the WTRU, a first PUCCH format or a third PUCCH format on a condition that the number of HARQ-ACK feedback bits is equal to zero and the number of CSI feedback bits is greater than zero;
selecting, by the WTRU, the first PUCCH format on a condition that the number of CSI feedback bits is greater than a second threshold; and
selecting, by the WTRU, the third PUCCH format on a condition that the number of CSI feedback bits is less than or equal to the second threshold.
4. The method of claim 1 , further comprising:
selecting, by the WTRU, a first PUCCH format or a fourth PUCCH format on a condition that the number of HARQ-ACK feedback bits is greater than zero and the number of CSI feedback bits is equal to zero;
selecting, by the WTRU, the first PUCCH format on a condition that the number of HARQ-ACK feedback bits is greater than a third threshold; and
selecting, by the WTRU, the fourth PUCCH format on a condition that the number of HARQ-ACK feedback bits is less than or equal to the third threshold.
5. The method of claim 1 , wherein at least one of the number of HARQ-ACK feedback bits for the HARQ-ACK feedback or the number of CSI feedback bits for the CSI feedback is determined based on a plurality of downlink assignments for carriers in the plurality of configured carriers.
6. The method of claim 1 , wherein at least one of the number of HARQ-ACK feedback bits for the HARQ-ACK feedback or the number of CSI feedback bits for the CSI feedback is determined based on at least one of a number of transport blocks, a number of carriers in the plurality of configured carriers or a number of subframes over which the transport blocks are received.
7. The method of claim 1 , wherein the plurality of configured carriers includes more than five configured carriers.
8. A wireless transmit/receive unit (WTRU) for uplink feedback for operating with a plurality of carriers, the WTRU comprising:
a transceiver; and
a processor operatively coupled to the transceiver;
wherein the transceiver is configured to receive a plurality of transport blocks over a plurality of configured carriers;
wherein the processor is configured to generate hybrid automatic repeat request (HARQ) acknowledgment (ACK) feedback for the plurality of transport blocks and channel state information (CSI) feedback for at least one of the plurality of configured carriers;
wherein the processor is configured to generate a feedback message that includes a number of HARQ-ACK feedback bits for the HARQ-ACK feedback and a number of CSI feedback bits for the CSI feedback;
wherein the processor is configured to determine a Physical Uplink Control Channel (PUCCH) format based on the number of HARQ-ACK feedback bits and the number of CSI feedback bits; and
wherein the transceiver is configured to transmit the feedback message using the determined PUCCH format.
9. The WTRU of claim 8 , wherein determining a PUCCH format further comprises the processor is configured to select a first PUCCH format or a second PUCCH format on a condition that the number of HARQ-ACK feedback bits is greater than zero and the number of CSI feedback bits is greater than zero;
wherein to select a first PUCCH format or a second PUCCH format comprises:
the processor is configured to select the first PUCCH format on a condition that a sum of the number of HARQ-ACK feedback bits and the number of CSI feedback bits is greater than a first threshold; and
wherein the processor is configured to select the second PUCCH format on a condition that a sum of the number of HARQ-ACK feedback bits and the number of CSI feedback bits is less than or equal to the first threshold.
10. The WTRU of claim 8 , wherein the processor is configured to select a first PUCCH format or a third PUCCH format on a condition that the number of HARQ-ACK feedback bits is equal to zero and the number of CSI feedback bits is greater than zero;
wherein the processor is configured to select the first PUCCH format on a condition that the number of CSI feedback bits is greater than a second threshold; and
wherein the processor is configured to select the third PUCCH format on a condition that the number of CSI feedback bits is less than or equal to the second threshold.
11. The WTRU of claim 8 , wherein the processor is configured to select a first PUCCH format or a fourth PUCCH format on a condition that the number of HARQ-ACK feedback bits is greater than zero and the number of CSI feedback bits is equal to zero;
wherein the processor is configured to select the first PUCCH format on a condition that the number of HARQ-ACK feedback bits is greater than a third threshold; and
wherein the processor is configured to select the fourth PUCCH format on a condition that the number of HARQ-ACK feedback bits is less than or equal to the third threshold.
12. The WTRU of claim 8 , wherein at least one of the number of HARQ-ACK feedback bits for the HARQ-ACK feedback or the number of CSI feedback bits for the CSI feedback is determined based on a plurality of downlink assignments for carriers in the plurality of configured carriers.
13. The WTRU of claim 8 , wherein at least one of the number of HARQ-ACK feedback bits for the HARQ-ACK feedback or the number of CSI feedback bits for the CSI feedback is determined based on at least one of a number of transport blocks, a number of carriers in the plurality of configured carriers or a number of subframes over which the transport blocks are received.
14. The WTRU of claim 8 , wherein the plurality of configured carriers includes more than five configured carriers.
15. A method, for uplink feedback for operating with a plurality of carriers, in a wireless transmit/receive unit (WTRU), the method comprising:
receiving, by the WTRU, a plurality of transport blocks over a plurality of configured carriers;
generating, by the WTRU, hybrid automatic repeat request (HARQ) acknowledgment (ACK) feedback for the plurality of transport blocks and channel state information (CSI) feedback for at least one of the plurality of configured carriers;
generating, by the WTRU, a feedback message that includes a number of HARQ-ACK feedback bits for the HARQ-ACK feedback and a number of CSI feedback bits for the CSI feedback;
determining, by the WTRU, one or more Physical Uplink Control Channel (PUCCH) resources based on the number of HARQ-ACK feedback bits and the number of CSI feedback bits; and
transmitting, by the WTRU, the feedback message using the determined one or more PUCCH resources.
16. The method of claim 15 , wherein determining one or more PUCCH resources comprises:
selecting, by the WTRU, first PUCCH resources or second PUCCH resources on a condition that the number of HARQ-ACK feedback bits is greater than zero and the number of CSI feedback bits is greater than zero;
wherein selecting first PUCCH resources or second PUCCH resources comprises:
selecting, by the WTRU, the first PUCCH resources on a condition that a sum of the number of HARQ-ACK feedback bits and the number of CSI feedback bits is greater than a first threshold; and
selecting, by the WTRU, the second PUCCH resources on a condition that a sum of the number of HARQ-ACK feedback bits and the number of CSI feedback bits is less than or equal to the first threshold.
17. The method of claim 15 , further comprising:
selecting, by the WTRU, first PUCCH resources or third PUCCH resources on a condition that the number of HARQ-ACK feedback bits is equal to zero and the number of CSI feedback bits is greater than zero;
selecting, by the WTRU, the first PUCCH resources on a condition that the number of CSI feedback bits is greater than a second threshold; and
selecting, by the WTRU, the third PUCCH resources on a condition that the number of CSI feedback bits is less than or equal to the second threshold.
18. The method of claim 15 , further comprising:
selecting, by the WTRU, first PUCCH resources or fourth PUCCH resources on a condition that the number of HARQ-ACK feedback bits is greater than zero and the number of CSI feedback bits is equal to zero;
selecting, by the WTRU, the first PUCCH resources on a condition that the number of HARQ-ACK feedback bits is greater than a third threshold; and
selecting, by the WTRU, the fourth PUCCH resources on a condition that the number of HARQ-ACK feedback bits is less than or equal to the third threshold.
19. The method of claim 15 , wherein at least one of the number of HARQ-ACK feedback bits for the HARQ-ACK feedback or the number of CSI feedback bits for the CSI feedback is determined based on a plurality of downlink assignments for carriers in the plurality of configured carriers.
20. The method of claim 15 , wherein at least one of the number of HARQ-ACK feedback bits for the HARQ-ACK feedback or the number of CSI feedback bits for the CSI feedback is determined based on at least one of a number of transport blocks, a number of carriers in the plurality of configured carriers or a number of subframes over which the transport blocks are received.