Patent ID: 8175176

Claim:
An FFT window spread generating method comprising: when OFDM-modulated received signals each having a time length greater than or equal to an effective OFDM symbol length are demodulated by FFT processing using a spread FFT window, combining the received signals located before and/or after the effective OFDM symbol length by a predetermined arithmetic operation in a FFT window generating arithmetic unit to generate the spread FFT window, and using the received signals each having the time length greater than or equal to the effective OFDM symbol length, providing spreading windows spread before and/or after the effective OFDM symbol length, adding together the received signals lying within the spreading windows to the received signals which correspond to the received signals lying within the effective OFDM symbol length and are different in time position by the effective OFDM symbol length, and reducing the amplitudes of the added received signals to half respectively, thereby generating the spread FFT window.