Method and device for transmitting ack/nack in wireless communication system

A method for transmitting an acknowledgement/not-acknowledgement (ACK/NACK) of UE in which a plurality of serving cells has been configured, the method comprising:

• receiving data in a subframe n−k of a second serving cell;
• and
• transmitting an ACK/NACK signal for the data in a subframe n of a first serving cell which is associated with the subframe n−k of the second serving cell,
• wherein the first serving cell is a primary cell in which the UE performs an initial connection establishment procedure or connection re-establishment procedure with a base station, and the first serving cell uses a Frequency Division Duplex (FDD) radio frame,
• the second serving cell is a secondary cell additionally allocated to the UE in addition to the primary cell, and the second serving cell uses a Time Division Duplex (TDD) radio frame, and
• in the subframe n−k, the k is determined to be a value identical with ACK/NACK timing of the second serving cell.

User Equipment (UE), comprising:

• a Radio Frequency (RF) unit transmitting and receiving radio signals;
• and
• a processor connected to the RF unit,
• wherein the processor receives data in a subframe n of a second serving cell and transmits an ACK/NACK signal for the data in a subframe n+kSCC(n) of a first serving cell which is associated with the subframe n of the second serving cell,
• the first serving cell is a primary cell in which the UE performs an initial connection establishment procedure or connection re-establishment procedure with a base station, and the first serving cell uses a Frequency Division Duplex (FDD) radio frame,
• the second serving cell is a secondary cell additionally allocated in addition to the primary cell, and the second serving cell uses a Time Division Duplex (TDD) radio frame, and
• the kSCC(n) is a predetermined value.