The base station first sends a high-frequency narrow beam of the region B1 to the mobile terminal in the region B1 according to the first scanning information, and the sending step lasts for a period of time T1. The mobile terminal successively receives, within T1, the high-frequency narrow beam of the region B1 regions U1, U2, U3, . . . , and UN. Afterwards, the base station sends a high-frequency narrow beam of the region B2 to the mobile terminal in the region B2, and the mobile terminal separately and successively receives, within T1, the high-frequency narrow beam of the region B2 in the regions U1, U2, U3 . . . , and UN. In such a sequence, the base station successively sends high-frequency narrow beams to the mobile terminal in total Q regions B1, B2, B3, . . . , and BQ. The mobile terminal receives, using Q×N high-frequency narrow beams in total, the Q high-frequency narrow beams sent by the base station, determines Q×N receiving statistics of received signals on the Q×N high-frequency narrow beams that are in a one-to-one correspondence with the Q scanning sectors and the N scanning sectors 1, and records the Q×N receiving statistics in a Q×N matrix.
Step 703: The mobile terminal sends a coarse scanning result to the base station using the low frequency channel.