A base station which communicates with a user equipment (UE) is described. The RRC configuration information may indicate that a maximum number of codewords scheduled by DCI is two. The base station may comprise transmitting circuitry configured to, after a channel access procedure, transmit, to the UE, a PDSCH which contains only a first transport block. The base station may further comprise receiving circuitry configured to receive, from the UE, a HARQ-ACK feedback including at least a first HARQ-ACK information bit and a second HARQ-ACK information bit. The first HARQ-ACK information bit may correspond to the first transport block of the PDSCH. The second HARQ-ACK information bit may be set to NACK. A contention window for the channel access procedure may be adjusted using the HARQ-ACK feedback, wherein the second HARQ-ACK information bit may be ignored.