A wireless communication terminal and a method for controlling power and using a channel by adjusting a channel bandwidth of the wireless communication terminal. The wireless communication terminal generates a plurality of channels by dividing at least part of a frequency band for ultra-wideband communications to a plurality of frequency bands, receives a chaotic signal having a plurality of frequency components in the channels, and adjusts a frequency bandwidth which forms the channel when a certain condition is satisfied. Accordingly, since the chaotic carrier is transmitted and received in the narrow frequency band by adjusting the frequency bandwidth, the power consumption can be reduced drastically and the high-quality communications are feasible between the portable terminal and the wireless headset in the optimized channel environment. Furthermore, a greater number of portable terminals and wireless headsets can execute the radio communications in a certain wireless communication range.