Optionally, the monitoring module 403 is configured to monitor a part or an entirety of third frequency resources in the K third frequency resources; and the processing module 404 is configured to: if the monitoring module 403 detects that H third frequency resources in the some or all third frequency resources are free, use at least one of the H third frequency resources as the target third frequency resource, where H is less than or equal to a quantity of the some or all third frequency resources, and H is a positive integer greater than or equal to 1.

Further optionally, the monitoring module 403 is specifically configured to monitor the some or all third frequency resources in the K third frequency resources according to a third predetermined rule; and/or the processing module 404 is specifically configured to select at least one of the H third frequency resources as the target third frequency resource according to a fourth predetermined rule.

The third predetermined rule includes at least one of the following: third frequency resources satisfying a first condition are monitored, and a quantity of monitored third frequency resources is less than or equal to a fourth threshold; and the fourth predetermined rule includes at least one of the following: third frequency resources satisfying the first condition are selected, and a quantity of selected third frequency resources is less than or equal to a fifth threshold; where the first condition is that a frequency measurement value corresponding to the third frequency resource is greater than or equal to a second threshold, the fourth threshold is less than or equal to K, and the fifth threshold is less than or equal to H.