In a possible manner, the terminal device receives the PDCCH transmitted by the network device, where the PDCCH is configured to transmit slot format indicator (SFI), and the SFI includes indication information of the subband for communication in the BWP. The terminal device determines the subband for communication in the BWP according to the indication information.

In another possible manner, the terminal device detects a reference signal on each of the multiple subbands included in the BWP to determine the subband for communication in the BWP. For example, if the reference signal is detected by the terminal device on subband 1, the terminal device determines that subband 1 is used for communication. If the reference signal is not detected by the terminal device on subband 0, the terminal device determines that subband 0 is not used for communication.

In another possible manner, the terminal device receives first indication information transmitted by the network device, and the first indication information instructs the terminal device to receive the control channel according to the second control resource set, to enable the terminal device to switch, according to the first indication information, from receiving the PDCCH according to the first control resource set to receiving the PDCCH according to the second control resource set. Optionally, the first indication information is physical layer signaling.

Optionally, the network device may also transmit second indication information to the terminal device. The second indication information is configured to indicate a position of the first control resource set, to enable the terminal device to determine the first control resource set before receiving the PDCCH according to the first control resource set. Optionally, the second indication information is radio resource control (RRC) signaling.