This invention relates to the proposal of component carrier (de)activation message that is allowing a activation or deactivation of one or more component carriers in the uplink or downlink. Furthermore, the invention relates to the use of the new component carrier (de)activation message in methods for (de)activation of downlink component carrier(s) configured for a mobile terminal, a base station and a mobile terminal. To enable efficient and robust (de)activation of component carriers, the invention proposes to use component carrier-specific or cell-RNTI(s) for the scrambling of the CRC of the component carrier (de)activation message, and to explicitly indicate the intended recipient of the component carrier (de)activation message in a corresponding field in the message. Furthermore, the invention further proposes different designs of the component carrier (de)activation message and further uses thereof, so as to trigger CQI reporting and/or SRS transmission by a mobile terminal.