A device in a wireless communication system, comprising: an obtaining unit for obtaining a signal quality of a mobile terminal with respect to a source cell; an evaluating unit for evaluating, according to a plurality of signal qualities of the mobile terminal with respect to the source cell which are obtained every predetermined period of time, a variation degree of the signal quality of the mobile terminal with respect to the source cell; and a triggering unit for triggering the mobile terminal, according to the variation degree of the signal quality of the mobile terminal with respect to the source cell, to report a measurement result; wherein the obtaining unit is further adapted to judge, according to the signal quality of the mobile terminal with respect to the source cell, whether a signal quality of the mobile terminal with respect to a target cell is obtained; and the evaluating unit is further adapted to evaluate a variation degree of signal qualities of the mobile terminal with respect to the source cell and the target cell, according to a plurality of signal qualities of the mobile terminal with respect to the source cell and the target cell which are obtained every predetermined period of time; wherein the evaluating unit is further adapted to determine an offset of the variations of the signal qualities of the mobile terminal with respect to the source cell and the target cell according to configuration parameters of the source cell, calculate a signal quality difference between the signal qualities of the mobile terminal with respect to the source cell and the target cell, and use a difference between the signal quality difference and the offset as a judgment threshold value for evaluating the variation degree of the signal qualities of the mobile terminal with respect to the source cell and the target cell. an obtaining unit for obtaining a signal quality of a mobile terminal with respect to a source cell; an evaluating unit for evaluating, according to a plurality of signal qualities of the mobile terminal with respect to the source cell which are obtained every predetermined period of time, a variation degree of the signal quality of the mobile terminal with respect to the source cell; and a triggering unit for triggering the mobile terminal, according to the variation degree of the signal quality of the mobile terminal with respect to the source cell, to report a measurement result; wherein the obtaining unit is further adapted to judge, according to the signal quality of the mobile terminal with respect to the source cell, whether a signal quality of the mobile terminal with respect to a target cell is obtained; and the evaluating unit is further adapted to evaluate a variation degree of signal qualities of the mobile terminal with respect to the source cell and the target cell, according to a plurality of signal qualities of the mobile terminal with respect to the source cell and the target cell which are obtained every predetermined period of time; wherein the evaluating unit is further adapted to determine an offset of the variations of the signal qualities of the mobile terminal with respect to the source cell and the target cell according to configuration parameters of the source cell, calculate a signal quality difference between the signal qualities of the mobile terminal with respect to the source cell and the target cell, and use a difference between the signal quality difference and the offset as a judgment threshold value for evaluating the variation degree of the signal qualities of the mobile terminal with respect to the source cell and the target cell.