This application discloses that a terminal device determines at least one target time parameter set based on N time parameter sets, where time unit lengths corresponding to at least two of the N time parameter sets are different; determines M target times based on a first time and the at least one target time parameter set, generates a codebook based on response information corresponding to downlink information received at at least one of the M target times, and sends the codebook to a network device at the first time. Correspondingly, the network device determines, based on the response information included in the codebook, whether the downlink information corresponding to the response information is successfully transmitted. Therefore, when the time unit lengths corresponding to the at least two of the N time parameter sets are different, the network device and the terminal device have a consistent understanding of the codebook.