In this possible implementation, for example, the terminal device includes a water meter, a smoke alarm, a mobile phone, and a computer. The core network device may determine, based on service features of the water meter and the smoke alarm, that a category to which the water meter and the smoke alarm belong is the category of uplink service trigger, and determine, based on service features of the mobile phone and the computer, that a category to which the mobile phone and the computer belong is the category of the downlink service trigger. In addition, after separately determining the categories to which the water meter, the smoke alarm, the mobile phone, and the computer respectively belong, the core network device sends the categories to which the water meter, the smoke alarm, the mobile phone, and the computer respectively belong to the corresponding water meter, smoke alarm, mobile phone, and computer. In addition, the water meter, the smoke alarm, the mobile phone, and the computer all receive a configuration of a plurality of wake up signals sent by the network device. For the configuration of the plurality of wake up signals, refer to the foregoing Table 2. Wake up signals corresponding to the category of the uplink service trigger are a wake up signal 1, a wake up signal 2, a wake up signal 3, and a wake up signal 4, and wake up signals corresponding to the category of the downlink service trigger are a wake up signal 5, a wake up signal 6, a wake up signal 7, and a wake up signal 8. For the water meter, the water meter may determine to-be-determined wake up signals in the eight wake up signals based on the category of the uplink service trigger to which the water meter belongs. The to-be-determined wake up signals are the wake up signal 1, the wake up signal 2, the wake up signal 3, and the wake up signal 4. Then, the water meter further determines the to-be-monitored wake up signal that the water meter needs to monitor in the four to-be-determined wake up signals: the wake up signal 1, the wake up signal 2, the wake up signal 3, and the wake up signal 4, based on a remainder obtained after the modulo-4 operation is performed on an identifier of the water meter. If the remainder obtained after the modulo-4 operation is performed on the identifier of the watch is 0, the water meter may determine, based on the group 1, that the to-be-monitored signal that the water meter needs to monitor is 1, and monitor the wake up signal 1. For the smoke alarm, the smoke alarm may determine to-be-determined wake up signals in the eight wake up signals based on the category of the uplink service trigger to which the smoke alarm belongs. The to-be-determined wake up signals are the wake up signal 1, the wake up signal 2, the wake up signal 3, and the wake up signal 4. Then, the smoke alarm further determines the to-be-monitored wake up signal that the smoke alarm needs to monitor in the four to-be-determined wake up signals: the wake up signal 1, the wake up signal 2, the wake up signal 3, and the wake up signal 4, based on a remainder obtained after the modulo-4 operation is performed on an identifier of the smoke alarm. If the remainder obtained after the modulo-4 operation is performed on the identifier of the smoke alarm is 2, the smoke alarm may determine, based on the group 3, that the to-be-monitored signal that the water meter needs to monitor is 3, and monitor the wake up signal 3. For the mobile phone, the mobile phone may determine to-be-determined wake up signals in the eight wake up signals based on the category of the downlink service trigger to which the mobile phone belongs. The to-be-determined wake up signals are the wake up signal 5, the wake up signal 6, the wake up signal 7, and the wake up signal 8. Then, the mobile phone further determines the to-be-monitored wake up signal that the mobile phone needs to monitor in the four to-be-determined wake up signals: the wake up signal 5, the wake up signal 6, the wake up signal 7, and the wake up signal 8, based on a remainder obtained after the modulo-4 operation is performed on an identifier of the mobile phone. If the remainder obtained after the modulo-4 operation is performed on the identifier of the smoke alarm is 1, the mobile phone may determine, based on the group 2, that the to-be-monitored signal that the water meter needs to monitor is 6, and monitor the wake up signal 6. For the computer, the computer may determine to-be-determined wake up signals in the eight wake up signals based on the category of the downlink service trigger to which the computer belongs. The to-be-determined wake up signals are the wake up signal 5, the wake up signal 6, the wake up signal 7, and the wake up signal 8. Then, the computer further determines the to-be-monitored wake up signal that the computer needs to monitor in the four to-be-determined wake up signals: the wake up signal 5, the wake up signal 6, the wake up signal 7, and the wake up signal 8, based on a remainder obtained after the modulo-4 operation is performed on an identifier of the computer. If the remainder obtained after the modulo-4 operation is performed on the identifier of the smoke alarm is 3, the computer may determine, based on the group 4, that the to-be-monitored signal that the water meter needs to monitor is 8, and monitor the wake up signal 8. In this way, when the core network device pages the mobile phone by using the wake up signal 6, for the water meter, the smoke alarm, the mobile phone, and the computer that are monitoring wake up signals, only the mobile phone can detect the wake up signal 6 and be woken up by the wake up signal 6. None of the water meter, the smoke alarm, and the computer detects the wake up signal 6 and is woken up. This reduces false alarm probabilities of paging of the water meter, the smoke alarm, and the computer, thereby reducing power consumption of the water meter, the smoke alarm, and the computer that are not paged.