An LTE-A system and power control method for controlling cell interference based on codeword-specific transmission power adjustment with a transmission power control offset parameter. The method includes transmitting a parameter KS signaled by a higher layer and codeword-specific power control parameters from a base station to a terminal; calculating gains at the terminal, using the codeword-specific power control parameters and the parameter KS; calculating, at the terminal, codeword-specific transmit powers according to the gains; and transmitting, from the terminal to the base station, at least two codewords at the codeword-specific transmit powers.