In a wireless communication technology, to reduce power consumption of a terminal device to monitor a physical downlink control channel (PDCCH) for paging, a concept of wake up signal (WUS) is introduced before each paging subframe (Paging Occasion, PO). The terminal device needs to monitor, in a conventional manner and on a corresponding PO, the PDCCH for paging, only after the terminal device detects, before the PO, a WUS. However, a plurality of terminal devices share one PO and a WUS before the PO. Therefore, provided that any terminal device belonging to the PO needs to be paged, another terminal device that is not paged also detects the WUS before the PO. To prevent a terminal device that is not paged from also detecting the WUS before the PO, a base station configures a plurality of wake up signals. A configuration of the plurality of wake up signals includes a mapping relationship between group information and a wake up signal. In other words, different group information corresponds to different wake up signals. In addition, the base station sends the configuration of the plurality of wake up signals to a terminal device, so that the terminal device may calculate, based on an identifier of the terminal device, a group to which the terminal device belongs, and then determine, based on the group and the mapping relationship, a wake up signal that the terminal device needs to monitor, so as to monitor the wake up signal, without a need to monitor a wake up signal corresponding to another group. In this way, when a terminal in a group needs to be paged, only a terminal device in the group detects the WUS before the PO, and a terminal device in another group does not detect the WUS before the PO, and therefore is not woken up. Theoretically, a quantity of woken-up terminal devices is decreased, thereby reducing a false alarm probability of paging.