User equipment apparatus for simultaneously transmitting signals via a plurality of wireless communication chips to which different wireless communication schemes are applied and method for controlling transmission power thereof

A method for controlling a transmission power at a user equipment, the method comprising:

• determining a transmission mode as to whether the user equipment is currently operated to transmit a signal through one wireless communication chip or to transmit a plurality of signals simultaneously through a first wireless communication chip and a second wireless communication chip;
• determining whether a set of frequencies of the plurality of signals transmitted from the first and second wireless communication chips causes intermodulation distortion if the determined transmission mode is a mode that transmits the plurality of signals simultaneously through the first and second wireless communication chips;
• and
• performing a first power back-off as much as a preset value for a transmission power of a signal to be transmitted from the second wireless communication chip having a lower priority than the first wireless communication chip if the set of the frequencies causes intermodulation distortion;
• wherein the performing the first power back-off comprises subtracting the preset value from a transmission power value of the signal to be transmitted from the second wireless communication chip.