In the mobile communication system 100, the radio access network device 120 is an access device through which the terminal device accesses the mobile communication system in a wireless manner. The radio access network device 120 may be a device configured to communicate with the terminal device. The network device may be a base transceiver station (BTS) in the global system for mobile communications (GSM) system or the code division multiple access (CDMA) system, a NodeB (NB) in the wideband code division multiple access (WCDMA) system, an evolved NodeB (eNB or eNodeB) in the LTE system, or a radio controller in a cloud radio access network (CRAN) scenario. Alternatively, the network device may be a relay node, an access point, a vehicle-mounted device, a wearable device, a network device in the future 5G network, a network device in a future evolved PLMN network, or the like. It should be understood that a specific technology and a specific device form that are used by the radio access network device are not limited in the embodiments of this application. In this application, the radio access network device is referred to as a network device for short. Unless otherwise specified, in this application, all network devices are radio access network devices. In this application, the network device may be a network device itself, or may be a chip used in the network device to complete a wireless communication processing function.

It should be understood that division of manners, cases, types, and embodiments in the embodiments of this application are merely for ease of description, but should not constitute any special limitation, and features in various manners, types, cases, and embodiments may be combined when there is no contradiction.