A method and a user equipment (UE) are described for transmitting power headroom (PH) information. The UE generates PH information, and transmits the PH information to a base station. The PH information includes a first field including a plurality of indicators, each of the plurality of indicators indicating the presence of a second field indicating a PH level of a corresponding secondary cell (SCell). The PH information further includes a type-1 PH field and a type-2 PH field for a primary cell (PCell). Each of the plurality of indicators is set to 0 or 1. An indicator, which has been set to 1, indicates that the second field exists for the corresponding SCell, and an indicator, which has been set to 0, indicates that the second field does not exist for the corresponding SCell.