Patent ID: 7627047

Claim:
An OFDM receiver apparatus mounted on a movable object for receiving an orthogonal frequency division multiplex (OFDM) signal, the OFDM receiver apparatus comprising: a plurality of directional antennas which receive an OFDM signal and output received signals, respectively; a moving velocity detector to detect a moving velocity of the movable object; a calculator to calculate a maximum Doppler center frequency from the moving velocity; an estimator to estimate a center frequency of a spectrum of a Doppler component in a frequency band not more than the maximum Doppler frequency from one of the received signals or a multiplexed signal obtained by multiplexing the received signals; a shift quantity calculator to calculate at least one shift quantity from the estimated center frequency of the estimator and directivity information representing directivity directions of the directional antennas; a plurality of frequency shifters to subject the received signals to frequency shift according to the shift quantity to compensate for Doppler shift; a combining unit configured to diversity-combine frequency shifted signals of the frequency shifters; and a demodulator/decoder to demodulate and decode combining diversity signals of the combining unit.