APPARATUS AND METHOD OF AUTOMATIC GAIN CONTROL IN A WIRELESS COMMUNICATION SYSTEM BY USE OF ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESSING

摘要

An automatic gain control (AGC) apparatus of a wireless mobile terminal, and method, in an orthogonal frequency division multiple access (OFDMA) system. A gain amplifier controls an amplification gain of received analog symbols. An analog-to-digital converter converts the received analog symbols into a digital signal. A fast Fourier transform (FFT) unit converts the digital signal into a frequency-domain signal. A power measurer measures power in the frequency domain in units of sub-carriers. A sub-carrier power accumulator detects a sub-camier carrying a signal, and accumulates its power value. A sub-carrier average power measurer estimates an average power value transmitted per sub-carrier from the accumulated power value. A control means compares the estimated average power value with a reference power value, and generates a control signal used for controlling a gain of the gain amplifier according to the comparison result.