Patent ID: 8824394

Claim:
A method of monitoring a control channel in a multiple carrier system, the method performed by a user equipment (UE) and comprising: receiving, by the UE, a first control format indicator (CFI) indicating a size of a control region of a first component carrier via the first component carrier; receiving, by the UE, downlink control information (DCI) comprising a cross-CFI indicating a size of a control region of a second component carrier being different than the first component carrier over a first downlink control channel in the control region of the first component carrier; receiving, by the UE via the second component carrier, a second CFI indicating the size of the control region of the second component carrier; receiving, by the UE, a higher layer signal including information on whether to use or discard the second CFI which is received via the second component carrier; determining whether to use the cross-CFI or the second CFI based on the higher layer signal; if the cross-CFI is determined to be used, monitoring, at the UE, a second downlink control channel in the control region of the second component carrier using the cross-CFI and discarding the second CFI; and if the second-CFI is determined to be used, monitoring, at the UE, a second downlink control channel in the control region of the second component carrier using at least the second-CFI.