A method, performed by a User Equipment (UE), includes receiving, from a base station (BS), a radio resource control (RRC) message comprising an information for configuring a Hybrid Automatic Repeat reQuest-ACKnowledge (HARQ-ACK) codebook list, first downlink control information (DCI) and second DCI; determining whether a size difference exists between a first downlink assignment index (DAI) field of the first DCI and a second DAI field of the second DCI; and inserting at least one bit with a zero value into one of the first DAI field and the second DAI field when the size difference between the first DAI field of the first DCI and the second DAI field of the second DCI is determined, wherein the HARQ-ACK codebook list includes a first HARQ-ACK codebook indicated by the first DCI and a second HARQ-ACK codebook indicated by the second DCI.