Beam selection method and communication apparatus

A method comprising:

• sending, by a network device, a downlink reference signal on a third beam;
• receiving, by the network device, power measurement results that are of a first beam and a second beam of a terminal and that are reported by the terminal, wherein the power measurement results of the first beam and the second beam comprise first reference signal receiving power (RSRP), second RSRP, first back-off power, and second back-off power, or the power measurement results of the first beam and the second beam comprise a difference between the first RSRP and the first back-off power and a difference between the second RSRP and the second back-off power;
• wherein
• the first RSRP is receiving power at which the terminal receives the downlink reference signal from the third beam using the first beam, the second RSRP is receiving power at which the terminal receives the downlink reference signal from the third beam using the second beam;
• when the difference between the first RSRP and the first back-off power is greater than a difference between the second RSRP and the first back-off power, determining, by the network device, that an uplink working beam of the terminal is the first beam;
• and
• sending, by the network device, a beam adjustment notification to the terminal, wherein the beam adjustment notification comprises the uplink working beam.

A communication apparatus, wherein the communication apparatus comprises a transceiver and a processor, wherein

• the transceiver is configured to receive, on a first beam and a second beam, a downlink reference signal from a third beam of a network device;
• the processor is configured to:
• perform reference signal receiving power (RSRP) measurement on the first beam to obtain first RSRP, and perform RSRP measurement on the second beam to obtain second RSRP, and perform maximum permissible exposure (MPE) measurement on the first beam to obtain first back-off power, and perform MPE measurement on the second beam to obtain second back-off power;
• and
• the transceiver is further configured to:
• when a difference between the first RSRP and the first back-off power is greater than a difference between the second RSRP and the first back-off power, send uplink data using the first beam;
• and wherein
• the first RSRP is receiving power at which the apparatus receives the downlink reference signal from the third beam using the first beam, the second RSRP is receiving power at which the apparatus receives the downlink reference signal from the third beam using the second beam.