Method for effectively transmitting control signal in wireless communication system

1. A method of transmitting a reception acknowledgement in a wireless communication system, performed by a user equipment, the method comprising:

determining M downlink subframes associated with an uplink subframe n at a specific uplink-downlink configuration, where M is the number of elements in a set K in accordance with the specific uplink-downlink configuration;

determining a counter value indicating a number of physical downlink control channels (PDCCHs) with an assigned physical downlink shared channel (PDSCH) transmission within downlink subframe n-k, where kεK, each PDCCH carrying a downlink assignment used for each PDSCH transmission, the downlink assignment including a bundling indicator indicating an accumulative number of PDCCHs with the assigned PDSCH transmission up to a present subframe corresponding to the downlink assignment;

determining a last bundling indicator having a value of a bundling indicator in a PDCCH detected by the user equipment in a downlink subframe n-ks, where ks is the smallest value in the set K;

determining whether at least one downlink assignment is missed based on the last bundling indicator and the counter value; and

transmitting an ACK/NACK signal on an uplink physical control channel (PUCCH) in the uplink subframe n if no downlink assignment is missed,

wherein the ACK/NACK signal is determined by a logical AND operation of ACK/NACKs for all PDSCH transmissions over the M downlink subframes; and

wherein a resource used for transmission of the PUCCH is associated with a resource used for transmission of a PDCCH carrying the downlink assignment in the downlink subframe n-ks.

2. The method of claim 1 , wherein the ACK/NACK signal is not transmitted if the at least one downlink assignment is missed.

3. The method of claim 1 , wherein the at least one downlink assignment is determined as missed if N DAI,last ≠(N DAI −1) mod 4+1, where N DAI,last denotes the value of the last bundling indicator, N DAI denotes the counter value and ‘mod’ denotes modulo operation.

4. The method of claim 1 , wherein the counter value further includes a number of PDCCHs intended for the user equipment.

5. The method of claim 1 , wherein the set K is defined as one of the following table in accordance with a subframe n and an uplink-downlink configuration:

uplink-

downlink

configura-

Subframe n

tion

0

1

2

3

4

5

6

7

8

9

0

—

—

6

—

5

—

—

6

—

4

1

—

—

6, 7

4

—

—

—

7, 6

4

—

2

—

—

8, 7, 4, 6

—

—

—

—

 8, 7,

—

—

4, 6

3

—

—

7, 6, 11

6, 5

5, 4

—

—

—

—

—

4

—

—

12, 8, 7, 11

6, 5, 4, 7

—

—

—

—

—

—

5

—

—

13, 12, 9,

—

—

—

—

—

—

—

8, 7, 5,

4, 11, 6

6

—

—

7

7

5

—

—

7

7

 —.

6. A user equipment of transmitting a reception acknowledgement in a wireless communication system, the user equipment comprising:

a radio frequency unit for receiving and transmitting radio signals; and

a processor operatively coupled with the radio frequency unit and configured for:

determining M downlink subframes associated with an uplink subframe n at a specific uplink-downlink configuration, where M is the number of elements in a set K in accordance with the specific uplink-downlink configuration;

determining a counter value indicating a number of physical downlink control channels (PDCCHs) with an assigned physical downlink shared channel (PDSCH) transmission within downlink subframe n-k, where kεK, each PDCCH carrying a downlink assignment used for each PDSCH transmission, the downlink assignment including a bundling indicator indicating an accumulative number of PDCCHs with the assigned PDSCH transmission up to a present subframe corresponding to the downlink assignment;

determining a last bundling indicator having a value of a bundling indicator in a PDCCH detected by the user equipment in a downlink subframe n-ks, where ks is the smallest value in the set K;

determining whether at least one downlink assignment is missed based on the last bundling indicator and the counter value; and

transmitting an ACK/NACK signal on an uplink physical control channel (PUCCH) in the uplink subframe n if no downlink assignment is missed,

wherein the ACK/NACK signal is determined by a logical AND operation of ACK/NACKs for all PDCCH transmissions over the M downlink subframes; and

wherein a resource used for transmission of the PUCCH is associated with a resource used for transmission of a PDCCH carrying the downlink assignment in the downlink subframe n-ks.

7. The user equipment of claim 6 , wherein the ACK/NACK signal is not transmitted if the at least one downlink assignment is missed.

8. The user equipment of claim 6 , wherein the processor is configured to determine that the at least one downlink assignment is missed if N DAI,last ≠(N DAI −1) mod 4+1, where N DAI,last denotes the value of the last bundling indicator, N DAI denotes the counter value and ‘mod’ denotes modulo operation.

9. The user equipment of claim 6 , wherein the counter value further includes a number of PDCCHs intended for the user equipment.

10. The user equipment of claim 6 , wherein the set K is defined as one of the following table in accordance with a subframe n and an uplink-downlink configuration:

uplink-

downlink

configura-

Subframe n

tion

0

1

2

3

4

5

6

7

8

9

0

—

—

6

—

5

—

—

6

—

4

1

—

—

6, 7

4

—

—

—

7, 6

4

—

2

—

—

8, 7, 4, 6

—

—

—

—

 8, 7,

—

—

4, 6

3

—

—

7, 6, 11

6, 5

5, 4

—

—

—

—

—

4

—

—

12, 8, 7, 11

6, 5, 4, 7

—

—

—

—

—

—

5

—

—

13, 12, 9,

—

—

—

—

—

—

—

8, 7, 5,

4, 11, 6

6

—

—

7

7

5

—

—

7

7

 —.