A method for controlling transmission powers by a communication apparatus in a wireless communication system supporting a plurality of component carriers, the method includes controlling transmission powers for one or more channels per each component carrier in such a way that a total transmission power of one or more channels in a corresponding component carrier does not exceed a maximum transmission power configured for the corresponding component carrier; when a simultaneous transmission of a sounding reference symbol (SRS) on a first component carrier, and a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH) on a second component carrier is scheduled, checking whether a total transmission power of the SRS, the PUSCH and PUCCH exceeds a maximum transmission power configured for the communication apparatus; and dropping a transmission of the SRS if the total transmission power of the SRS, the PUSCH and PUCCH exceeds the maximum transmission power configured for the communication apparatus.