According to the present invention, a first physical downlink control channel (PDCCH) and a second PDCCH can be transmitted to user equipment. A first physical downlink data channel (PDSCH) corresponding to the first PDCCH, and a second PDSCH corresponding to the second PDCCH can be transmitted to the user equipment. When the first PDSCH has a lower decoding priority than the second PDSCH, and the decoding timing of the first PDSCH and the decoding timing of the second PDSCH overlap, the user device may decode the second PDSCH and not the first PDSCH at the decoding timing, and transmit information with respect to the first PDSCH as first ACK/NACK information. As a reply to the first ACK/NACK information, a third PDCCH not having a corresponding PDSCH may be transmitted to the user equipment.