In an exemplary embodiment there is sent to a user equipment UE downlink control information DCI comprising an indication of an access codeword and an indication that at least one component carrier CC is activated for the UE, and there is received from the UE the access codeword which is an acknowledgement that the UE has activated the at least one CC. The access codeword is received on an uplink channel which a) lies in the at least one activated CC if there is an activated uplink channel in the activated CC, or b) is previously activated if there is no activated uplink channel in the activated CC. In another embodiment DCI comprising the above two indications is received from a network, the received indications are used to select and access the at least one CC; and activating the CC is acknowledged by sending the access codeword.