Method and device for transmitting signal in wireless communication system

A base station configured to receive a hybrid automatic repeat request (HARQ-ACK) payload in a carrier aggregation (CA) wireless communication system, the base station comprising:

• a radio frequency (RF) unit;
• and
• a processor,
• wherein the processor is configured to:
• transmit a first physical downlink control channel (PDCCH) for downlink scheduling through one of plural cells in a time interval, the first PDCCH including a first downlink assignment index (DAI) and a second DAI;
• transmit a downlink data based on the first PDCCH;
• and
• receive the HARQ-ACK payload including HARQ-ACK information for the downlink data generated by a user equipment (UE) based on the first and second DAIs,
• wherein the first DAI is related to a counter value of the downlink scheduling, the counter value being counted in a cell prioritized manner in a unit of {cell, time interval} pair, and
• wherein the second DAI is related to a total number of downlink scheduling(s) over the plural cells, up to a current time interval within a set of time intervals, the total number being updated from time interval to time interval, and the second DAI has a same value as other second DAIs corresponding to a plurality of first PDCCHs and received in a same time interval.