(1) Network device: The network device is a device that is in a network and that connects a terminal device to a wireless network. The network device is a node in a radio access network, and may also be referred to as a base station or a radio access network (RAN) node (or device). Currently, some network devices are, for example, a gNB, a transmission reception point (TRP), an evolved NodeB (eNB), a radio network controller (RNC), a NodeB (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, a home evolved NodeB or a home NodeB, HNB), a baseband unit (BBU), and a wireless fidelity (Wifi) access point (AP). In addition, in a network structure, the network device may include a centralized unit (CU) node and a distributed unit (DU) node. In this structure, a protocol layer of an eNB in a long term evolution (LTE) system is split, some functions of the protocol layer are controlled by a CU in a centralized manner, remaining or all functions of the protocol layer are distributed in DUs, and the CU controls the DUs in a centralized manner.
(2) Terminal device: The terminal device is also referred to as user equipment (UE), a mobile station (MS), a mobile terminal (MT), or the like, and is a device that provides a user with voice and/or data connectivity, for example, a handheld device or a vehicle-mounted device having a wireless connection function. Currently, some terminals are, for example, a mobile phone, a tablet computer, a notebook computer, a palmtop computer, a mobile internet device (MID), a wearable terminal, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, and a wireless terminal in a smart home.