Patent ID: 7548522

Claim:
In a wireless communication system for transmitting and receiving data by using a multipath fading channel, an OFDM (orthogonal frequency division multiplexing) wireless communication system comprising: a transmitter for performing IDFT (inverse discrete Fourier transform) on-information transmit vectors at least twice to modulate them into an OFDM (orthogonal frequency division multiplexing) signals, transmitting the modulated OFDM signals through a multipath fading channel, modulating a pilot symbol vector for predicting an amplitude and a phase of the multipath fading channel into an OFDM signal, and transmitting the modulated OFDM signal through the multipath fading channel; and a receiver for demodulating the pilot symbol vector received through the multipath fading channel to predict the amplitude and the phase of the multipath fading channel, using the predicted amplitude and phase to compensate the amplitude and the phase multiplied to the received information transmit vectors, performing DFT (discrete Fourier transform) on the compensated information transmit vectors to average a noise signal value increased by the channel compensation in a specific interval with an amplitude of the channel with less than a mean value into a mean value within an OFDM symbol interval, and outputting the mean value, wherein the transmitter comprises a first IDFT unit for performing IDFT on the information transmit vectors and outputting IDFT-performed signals; and a second IDFT unit for performing IDFT on the IDFT-performed signals output from the first IDFT unit to modulate them into OFDM signals, and wherein the receiver comprises a first DFT unit for demodulating the received information transmit vectors into OFDM signals; and a second DFT unit for performing DFT on the compensated information transmit vectors and averaging a noise signal value which becomes enhanced in a specific interval with an amplitude of the channel with less than a mean value, to a mean value within a symbol interval.