Method for establishing downlink HARQ-ACK timing and apparatus therefor

1. A method of establishing, by a user equipment, downlink HARQ-ACK timing when a primary cell and a secondary cell having different duplex modes are established for the user equipment, the method comprising:

receiving, by the user equipment, a downlink signal on the secondary cell; and

applying, by the user equipment, HARQ-ACK timing established to be used in the duplex mode of the primary cell as HARQ-ACK timing regarding the received downlink signal, when the user equipment transmits an HARQ-ACK for the downlink signal on the primary cell,

wherein when the primary cell is established as a time division duplex (TDD) primary cell and the secondary cell is established as a frequency division duplex (FDD) secondary cell,

the applying of the HARQ-ACK timing comprises applying HARQ-ACK timing included in an uplink subframe-specific downlink association set established to be used in the TDD primary cell, as HARQ-ACK timing for the downlink signal received on the FDD secondary cell,

wherein when an interval of a switch-point periodicity of the uplink subframe-specific downlink association set established for the TDD primary cell is K where the K is one of 5 and 10, the applying of the HARQ-ACK timing comprises: adding, by the user equipment the K to the uplink subframe-specific downlink association set; and applying the K added uplink subframe-specific downlink association set as HARQ-ACK timing for the TDD primary cell and the FDD secondary cell regarding the downlink signal

wherein the applying of the HARQ-ACK timing comprises: applying, by the user equipment HARQ-ACK timing added to a single uplink subframe within a switch-point periodicity established for the TDD primary cell, as HARQ-ACK timing regarding the downlink signal, and wherein when an interval of the switch-point is 10 subframes, the single uplink subframe is a subframe 2 , and when the interval of the switch-point is 5 subframes, the single uplink subframe is a subframe 3 , and

wherein the applying of the HARQ-ACK timing comprise: applying, by the user equipment HARQ-ACK timing added to the uplink subframe-specific downlink association set of the TDD primary cell according to a sequence of a downlink subframe in which the downlink signal is transmitted, as HARQ-ACK timing regarding the downlink signal.

2. The method according to claim 1 wherein, when two or more uplink subframes are present within a switch-point periodicity of the TDD primary cell, the HARQ-ACK timing regarding the downlink signal is distributed to the two or more uplink subframes.

3. A method of establishing, by a base station, downlink HARQ-ACK timing when establishing a primary cell and a secondary cell having different duplex modes for user equipment, the method comprising:

transmitting, by the base station, a downlink signal to the user equipment on the secondary cell; and

receiving, by the base station through the primary cell, an HARQ-ACK in response to the downlink signal from the user equipment, on an uplink subframe to which HARQ-ACK timing established to be used in the duplex mode of the primary cell is applied,

wherein when the primary cell is established as a time division duplex (TDD) primary cell and the secondary cell is established as a frequency division duplex (FDD) secondary cell,

the applying of the HARQ-ACK timing comprises applying HARQ-ACK timing included in an uplink subframe-specific downlink association set established to be used in the TDD primary cell, as HARQ-ACK timing for the downlink signal transmitted on the FDD secondary cell,

wherein when an interval of a switch-point periodicity of the uplink subframe-specific downlink association set established for the TDD primary cell is K where the K is one of 5 and 10, the receiving of the HARQ-ACK comprises: receiving, in the base station, the HARQ-ACK for the TDD primary cell and the FDD secondary cell regarding the downlink signal regarding the downlink signal from the user equipment on an uplink subframe to which HARQ-ACK timing in which the K is added to the uplink subframe-specific downlink association set is applied,

wherein the receiving of the HARQ-ACK comprises: receiving, by the base station, the HARQ-ACK in response to the downlink signal from the user equipment on a single uplink subframe within a switch-point periodicity established for the TDD primary cell wherein added HARQ-ACK timing is applied to the uplink subframe, and wherein when an interval of the switch-point periodicity is 10 subframes, the single uplink subframe is subframe 2 , and when the interval of the switch-point periodicity is 5 subframes, the single uplink subframe is a subframe 3 , and

wherein the receiving of the HARQ-ACK comprises receiving, by the base station, the HARQ-ACK in response to the downlink signal from the user equipment on an uplink subframe in which added HARQ-ACK timing is applied to the uplink subframe-specific downlink association set of the TDD primary cell according to a sequence of a downlink subframe in which the downlink signal is transmitted.

4. The method according to claim 3 , wherein, when two or more uplink subframes are present within a switch-point periodicity of the TDD primary cell, HARQ-ACK timing regarding the downlink signal is distributed to the two or more uplink subframes.

5. A user equipment for establishing downlink HARQ-ACK timing when a primary cell and a secondary cell having different duplex modes are established for the user equipment, the user equipment comprising:

a receiver configured to receive a downlink signal on the second cell; and a controller configured to apply HARQ-ACK timing established to be used in the duplex mode of the primary cell as HARQ-ACK timing regarding the received downlink signal, when the user equipment transmits an HARQ-ACK signal for the downlink signal on the primary cell,

wherein when the primary cell is established as a time division duplex (TDD) primary cell and the secondary cell is established as a frequency division duplex (FDD) secondary cell,

the applying of the HARQ-ACK timing comprises applying HARQ-ACK timing included in an uplink subframe-specific downlink association set established to be used in the TDD primary cell, as HARQ-ACK timing for the downlink signal received on the FDD secondary cell,

wherein when an interval of a switch-point periodicity of the uplink subframe-specific downlink association set established for the TDD primary cell is K, the controller is configured to: add the K to the uplink subframe-specific downlink association set; and apply the K added uplink subframe-specific downlink association set as HARQ-ACK timing for the TDD primary cell and the FDD secondary cell regarding the downlink signal wherein the K is one of 5 and 10,

wherein the controller is configured to apply HARQ-ACK timing added to a single uplink subframe within a switch-point periodicity established for the TDD primary cell as HARQ-ACK timing regarding the downlink signal and wherein when an interval of the switch-point periodicity is 10 subframes, the single uplink subframe is a subframe 2 , and when the interval of the switch-point periodicity is 5 subframes, the single uplink subframe is a subframe 3 , and

wherein the controller is configured to apply HARQ-ACK timing added to the uplink subframe-specific downlink association set of the TDD primary cell according to a sequence of a downlink subframe in which the downlink signal is transmitted, as HARQ-ACK timing regarding the downlink signal.

6. The user equipment according to claim 5 , wherein when two or more uplink subframes are present within a switch-point periodicity of the TDD primary cell, the HARQ-ACK timing regarding the downlink signal is distributed to the two or more uplink subframe.