A method for controlling transmission powers by a communication apparatus in a wireless communication system supporting a plurality of component carriers; and a communication apparatus therefore are discussed. The method according to one embodiment includes controlling transmission powers for one or more channels per each component carrier; when a sounding reference symbol (SRS) transmission overlaps with a physical uplink shared channel (PUSCH) transmission in a time domain, checking whether a total of a PUSCH transmission power for the PUSCH transmission on a first component carrier and a SRS transmission power for the SRS transmission on a second component carrier exceeds a maximum transmission power configured for the communication apparatus; and dropping the SRS if the total of the PUSCH transmission power and the SRS transmission power exceeds the maximum transmission power configured for the communication apparatus.