Embodiments of the present disclosure relate to methods and apparatuses for HARQ-ACK codebook reduction. According to an embodiment of the present disclosure, a method can include: transmitting a plurality of uplink data channels to a BS; and receiving a HARQ-ACK codebook in first DCI indicating downlink feedback. At least one of the plurality of uplink data channels is configured by the BS, and each uplink data channel is associated with each HARQ process. The HARQ-ACK codebook includes at least two sub-codebooks: a first sub-codebook including TB-level HARQ-ACK information bits for a first set of HARQ processes and a second sub-codebook including CBG-level HARQ-ACK information bits for a second set of HARQ processes. The first DCI has the same size with the second DCI for scheduling uplink data transmission. Embodiments of the present disclosure can ensure both UE side and BS side have the same understanding on the reduced HARQ-ACK codebook.