Patent ID: 8687581

Claim:
A method for transmitting control information from a base station of a wireless communications system supporting carrier aggregation where non-backward compatible component carrier (NBC CC) and backward compatible component carrier (BC CC) coexist, the method comprising the steps of: transmitting information on physical cell ID (physical cell identification or PCI) for use in uplink signal transmission, to a user equipment; and receiving an uplink signal, which is generated using the PCI, from the user equipment, wherein, if non-backward compatible downlink component carrier (NBC DL CC) and backward compatible downlink component carrier (BC DL CC) are aggregated by carrier aggregation and connected with one uplink component carrier (UL CC), the step of transmitting information on PCI includes transmitting information on PCI of the BC DL CC through the NBC DL CC, and the step of receiving an uplink signal includes receiving the uplink signal generated based on the PCI of the BC DL CC.