A device and method in a radio communication system. The device includes: an acquisition unit for use in acquiring a signal quality of a mobile terminal relative to a source cell; an assessment unit for use in assessing the degree of change in the signal quality of the mobile terminal relative to the source cell on the basis of multiple signal qualities of the mobile terminal relative to the source cell acquired at every predetermined time interval; and, a triggering unit for use in triggering, on the basis of the degree of change in the signal quality of the mobile terminal relative to the source cell, the mobile terminal to submit a measurement result.