Apparatus and method for controlling uplink transmission power in a multiple element carrier wave system

A user equipment for controlling uplink transmission power in a multiple component carrier system, comprising:

• a signal generation unit generating an uplink signal to be transmitted on a first serving cell;
• a reception unit receiving from a base station random access initiate information commanding initiation of a random access procedure with respect to a second serving cell;
• a power adjustment unit calculating estimated power headroom based on both a first transmission power scheduled for transmission of the uplink signal and a second transmission power scheduled for transmission of a Physical Random Access Channel (PRACH) to which a random access preamble is mapped, comparing the estimated power headroom with a threshold power, and adjusting the first transmission power and the second transmission power based on a power allocation priority;
• and
• a transmission unit, if the estimated power headroom is less than threshold power, transmitting the uplink signal and the PRACH at the same time by the adjusted first transmission power and the adjusted second transmission power or transmitting selectively either the uplink signal or the PRACH based on the power allocation priority.