Selection of acknowledgment timing in wireless communications

1. An apparatus for a user equipment (UE) comprising:

baseband circuitry including processing circuitry configured to provide a Frequency Division Duplex-Time Division Duplex (FDD-TDD) hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback procedure for a primary serving cell (PCell) frame structure type-2, further configured to:

establish a connection to the primary serving cell (PCell) and a secondary serving cell (SCell) of an enhanced-Node B (eNB) of the LTE wireless communication network, the PCell having a TDD configuration and the SCell having a FDD configuration;

categorize a type of downlink data subframe in use by the SCell; and

select a hybrid automatic repeat request (HARQ) timing sequence configuration for use with downlink data received from the SCell based on the type of downlink data subframe received from the SCell; and transceiver circuitry to

receive the downlink data through the PCell and SCell; and

transmit acknowledgement information associated with the downlink data subframe received from the SCell according to the selected hybrid automatic repeat request (HARQ) timing sequence configuration in an uplink (UL) subframe over the connection to the PCell;

wherein the PCell uses Type-2 subframes and the SCell uses Type-1 subframes,

wherein the UE is configured to not monitor a Physical Downlink Control Channel (PDCCH)/Enhanced Physical Downlink Control Channel (EPDCCH) in another serving cell for scheduling the serving cell;

wherein a timing sequence configuration with which to transmit an acknowledgement/negative acknowledgement (ACK/NACK) comprises a table including values associated with an ACK/NACK for a DL subframe on the SCell to be transmitted in the UL subframe on the PCell, wherein a UL ACK/NACK transmission of subframe n is in subframe n-k, where k>=4.

2. The apparatus of claim 1 , wherein the table comprises:

DL-reference

UL/DL

Subframe n

Configuration

0

1

2

3

4

5

6

7

8

9

0

—

—

6, 5

5, 4

4

—

—

6, 5

5, 4

4

1

—

—

7, 6

6, 5,

—

—

—

7, 6

6,

—

4

5, 4

2

—

—

8, 7, 6, 5, 4

—

—

—

—

8, 7, 6,

—

—

5, 4

3

—

—

11, 10, 9, 8, 7, 6

6, 5

5, 4

—

—

—

—

—

4

—

—

12, 11, 10, 9, 8, 7

7, 6,

—

—

—

—

—

—

5, 4

5

—

—

13, 12, 11, 10, 9,

—

—

—

—

—

—

—

8, 7, 6, 5, 4

6

—

—

8, 7

7, 6

6, 5

—

—

7

7,

—

6, 5.

3. The apparatus of claim 2 , wherein the DL-reference UL/DL Configuration of the timing sequence configuration is defined by the following table:

Uplink-

Downlink-

downlink

to-Uplink

config-

Switch-point

Subframe number

uration

periodicity

0

1

2

3

4

5

6

7

8

9

0

5

ms

D

S

U

U

U

D

S

U

U

U

1

5

ms

D

S

U

U

D

D

S

U

U

D

2

5

ms

D

S

U

D

D

D

S

U

D

D

3

10

ms

D

S

U

U

U

D

D

D

D

D

4

10

ms

D

S

U

U

D

D

D

D

D

D

5

10

ms

D

S

U

D

D

D

D

D

D

D

6

5

ms

D

S

U

U

U

D

S

U

U

 D.

4. The apparatus of claim 1 , wherein the processing circuitry is further configured to select a hybrid automatic repeat request (HARQ) timing sequence configuration for use by the PCell based on the type of downlink data subframe.

5. The apparatus of claim 1 , wherein the processing circuitry is further configured to select a hybrid automatic repeat request (HARQ) timing sequence configuration for use on the PCell based on a PCell TDD uplink-downlink timing sequence configuration indicated in a received first system information block (SIB 1 ) when the PCell is TDD configured.

6. The apparatus of claim 1 , wherein the Type-1 downlink data subframe comprises a subframe that is a downlink data subframe on both the PCell and the SCell, or that is a downlink data subframe on both a scheduling cell and a scheduled cell in a case of a cross-carrier scheduling configuration, and wherein more than one TDD serving cell is configured and the configured scheduling cell is not the PCell; and/or

wherein the Type-2 downlink data subframe comprises a subframe that is downlink only on the SCell.

7. The apparatus of claim 1 , wherein:

i) the selected HARQ timing sequence configuration for DL data transmission in subframe n-k, where k>=4, comprises transmitting a HARQ in a first available UL subframe n on PCell; or

ii) the HARQ timing sequence configuration selected for DL data transmission in subframe n-k, where k>=4, comprises transmitting a HARQ in an available UL subframe n on PCell in a distributed fashion across available UL subframes.

8. The apparatus of claim 1 , wherein the processing circuitry is configured to transmit acknowledgement information associated with the downlink data according to the selected hybrid automatic repeat request (HARQ) timing sequence configuration and comprises being configured to transmit acknowledgement information on a physical uplink shared channel (PUSCH) on the PCell.

9. The apparatus of claim 1 , wherein the processing circuitry is configured to transmit acknowledgement information comprising transmitting for a PCell PDSCH or a SCell PDSCH on a UL subframe of a PUSCH or physical uplink control channel (PUCCH) on PCell.

10. A machine readable medium comprising a plurality of non-transitory instructions that, in response to being executed on a computing device, cause the computing device to carry out a method comprising:

associating, by a user equipment (UE), with the primary serving cell (PCell) and a secondary serving cell (SCell) of an enhanced-Node B (eNB), the PCell having a TDD configuration and the SCell having a FDD configuration, wherein the PCell uses Type-2 subframes and the SCell uses Type-1 subframes;

categorizing a type of downlink data subframe in use by the SCell;

selecting, by the UE, a hybrid automatic repeat request (HARQ) timing sequence configuration for use by the SCell based on the type of downlink data subframe received from the SCell;

receiving, by the UE, downlink data through the PCell and SCell; and

transmitting acknowledgement information associated with the downlink data according to the selected hybrid automatic repeat request (HARQ) timing sequence configuration in an uplink (UL) subframe over the connection to the PCell;

wherein the UE does not monitor a Physical Downlink Control Channel (PDCCH)/Enhanced Physical Downlink Control Channel (EPDCCH) in another serving cell for scheduling the serving cell; and

wherein transmitting acknowledgement information comprises transmitting an acknowledgement/negative acknowledgement (ACK/NACK) according to a timing sequence configuration comprising a table including values associated with an ACK/NACK for a DL subframe on the SCell to be transmitted in the UL subframe on the PCell, wherein a UL ACK/NACK transmission of subframe n is in subframe n-k, where k>=4.

11. The method of claim 1 , wherein the table comprises:

DL-reference

UL/DL

Subframe n

Configuration

0

1

2

3

4

5

6

7

8

9

0

—

—

6, 5

5, 4

4

—

—

6, 5

5, 4

4

1

—

—

7, 6

6, 5,

—

—

—

7, 6

6,

—

4

5, 4

2

—

—

8, 7, 6, 5, 4

—

—

—

—

8, 7, 6,

—

—

5, 4

3

—

—

11, 10, 9, 8, 7, 6

6, 5

5, 4

—

—

—

—

—

4

—

—

12, 11, 10, 9, 8,

7, 6,

—

—

—

—

—

—

7

5, 4

5

—

—

13, 12, 11, 10, 9,

—

—

—

—

—

—

—

8, 7, 6, 5, 4

6

—

—

8, 7

7, 6

6, 5

—

—

7

7,

—

6, 5.

12. The machine readable medium of claim 10 , wherein the DL-reference UL/DL Configuration of the timing sequence configuration is defined by the following table:

Uplink-

Downlink-

downlink

to-Uplink

config-

Switch-point

Subframe number

uration

periodicity

0

1

2

3

4

5

6

7

8

9

0

5

ms

D

S

U

U

U

D

S

U

U

U

1

5

ms

D

S

U

U

D

D

S

U

U

D

2

5

ms

D

S

U

D

D

D

S

U

D

D

3

10

ms

D

S

U

U

U

D

D

D

D

D

4

10

ms

D

S

U

U

D

D

D

D

D

D

5

10

ms

D

S

U

D

D

D

D

D

D

D

6

5

ms

D

S

U

U

U

D

S

U

U

 D.

13. The machine readable medium of claim 9 , wherein the hybrid automatic repeat request (HARQ) timing sequence configuration is selected by a PCell TDD uplink-downlink timing sequence configuration indicated in a first system information block (SIB 1 ) configuration when PCell is TDD.

14. The machine readable medium of claim 10 , wherein the Type-1 downlink data subframe comprises a subframe that is a downlink data subframe on both the PCell and the SCell, or that is a downlink data subframe on both a scheduling cell and a scheduled cell in a case of a cross-carrier scheduling configuration, and wherein more than one TDD serving cell is configured and the configured scheduling cell is not the PCell, and/or

wherein the Type-2 of downlink data subframe comprises a subframe that is downlink only on the SCell.

15. The machine readable medium of claim 10 , the HARQ timing sequence configuration for DL data transmission in subframe n-k, where k>=4, comprises transmitting a HARQ in a first available UL subframe n on PCell; or

wherein the HARQ timing sequence configuration for DL data transmission in subframe n-k, where k>=4, comprises transmitting a HARQ in an available UL subframe n on PCell in a distributed fashion across available UL subframes.