According to a second aspect, an embodiment of this application provides a communications apparatus. The communications apparatus includes a processor, the processor is coupled to a memory, and the memory is configured to store an instruction. The processor is configured to execute the instruction stored in the memory, to perform the method in any one of the first aspect or the possible designs of the first aspect. Optionally, the communications apparatus may further include the memory. Optionally, the communications apparatus may further include a transceiver, configured to support the communications apparatus in sending and/or receiving information in the foregoing method. Optionally, the communications apparatus may be a terminal device, or may be an apparatus in a terminal device, for example, a chip or a chip system. The chip system includes at least one chip, and the chip system may further include another circuit structure and/or discrete component.

According to a third aspect, an embodiment of this application provides a communications apparatus, configured to implement the method in any one of the first aspect or the possible designs of the first aspect. The communications apparatus includes corresponding functional modules respectively configured to implement the steps in the foregoing method, for example, a processing unit and a transceiver unit.

According to a fourth aspect, an embodiment of this application provides a communications method. The method includes: receiving, by a network device, a message 3 sent by a terminal device; and when determining that the message 3 includes a first media access control layer control element MAC CE, determining, by the network device, quality of a channel between the network device and the terminal device based on channel quality information in the first MAC CE.