Method and device for transmitting sounding reference signal

TDD (time division duplex) and FDD cell sounding reference is performed by a plurality of serving cells is set, the wireless device having the (frequency division duplex) cell, a signal transmission method is provided. The wireless device receives the downlink control information according to a second serving cell from the first serving cell. The wireless device determines whether to transmit the sounding reference simho depending on whether the the downlink control information includes an aperiodic SRS (sounding reference signal) request.