One disclosure of the present specification provides a method for identifying a secondary cell on the basis of discovery signals. The method may comprise the step of receiving information on a discovery signal measurement timing configuration (DMTC) and a measurement cycle from a serving cell. The DMTC may include a DMTC periodicity. The measurement cycle may indicate the measurement cycle of an inactivated secondary cell (Scell) by subframe unit. The method may comprise the step of identifying the secondary cell. If DRX is used, the secondary cell is considered an intra-frequency cell, and the secondary cell is a small cell and identified based on discovery signals, the identification of the small cell can be performed in two hours.