Method for detecting a structure of downlink control for adding carrier

A method for detecting a structure of downlink control for adding carrier in a communications network in which data transmission is planned by a physical control channel downlink PDCCH, the method including, in a computer of user, EU: receiving signaling in the upper layer that enables adding carrier to the UE, and read the PDCCHs of component carriers, CCs, wherein the control information downlink DCI, reads the PDCCHs of CCs according to one of a plurality of predefined formats derived signaling in the upper layer.