Method for transmitting ack/nack information to uplink physical control channel

Disclosed is a communication system which transmits ACK/NACK information on downlink data by using an uplink control channel. The communication system individually allocates radio resources for a plurality of slots included in an uplink sub frame. Consequently, uplink radio resources may be used freely, and it is even possible to flexibly handle a situation in which the amount of the ACK/NACK information is increased.