A power controllable wireless mobile communications system using an adaptive modulation and coding scheme includes a signal-to-noise ratio (SNR) extracting unit which extracts a SNR from a received signal that is processed using a predetermined first modulation and coding scheme; a modulation and coding scheme determining unit which compares the extracted SNR with a first requested SNR for the received signal and determines a second modulation and coding scheme; a power control value determining unit which compares the extracted SNR with a second requested SNR for a signal of the second modulation and coding scheme and determines a power control value; and a signal generating unit which inserts a field indicating the second modulation and coding scheme and a power control command field for the power control value, into data to be transmitted, processes a resulting signal according to the second modulation and coding scheme, and generates a transmission signal.