In a communication system, subchannel state information for a plurality of user equipments (UEs) are collected, and a plurality of subchannel state prediction parameter values for the respective UEs are calculated using the subchannel state information. In addition, the communication system allocates at least one subchannel among the plurality of subchannels to a first UE having the highest priority. Subsequently, the communication system determines whether to allocate additional power to the at least one subchannel based on the plurality of subchannel state prediction parameter values, and allocates additional power to a subchannel that needs the additional power among the at least one subchannel.