A base station of a wireless communication system is disclosed. The base station of the wireless communication includes a communication module, and a processor. The processor is configured to, when receiving a physical downlink control channel (PDCCH) indicating a change of a downlink (DL) bandwidth part (BWP), change the DL BWP based on the PDCCH indicating the change of the DL BWP, and not include a physical downlink shared channel (PDSCH) scheduled by a PDCCH received before receiving the PDCCH indicating the change of the DL BWP in a PDSCH candidate set, and transmit a semi-static HARQ-ACK codebook including hybrid automatic repeat request (HARQ)-ACK information of a physical downlink shared channel (PDSCH) corresponding to the PDSCH candidate set to a base station of the wireless communication system.