Patent ID: 7636366

Claim:
An OFDM radio communications system comprising a plurality of transmitters transmitting OFDM signals and a receiver conducting macro-diversity reception based on the OFDM signals, wherein each of the transmitters comprises: first allocation means for allocating pilot signals to a first pilot subcarrier and a second pilot subcarrier different in frequency, respectively; second allocation means for allocating macro-diversity signals subjected to macro-diversity to a first data subcarrier, whose frequency is the same as a frequency of the first pilot subcarrier and whose transmission timing is successive to a transmission timing of the first pilot subcarrier, and a second data subcarrier, whose frequency is the same as a frequency of the second pilot subcarrier and whose transmission timing is successive to a transmission timing of the second pilot subcarrier; third allocation means for allocating a non-macro-diversity signal not subjected to macro-diversity to a third data subcarrier whose frequency is between the frequency of the first pilot subcarrier and the frequency of the second pilot subcarrier and whose transmission timing is between the transmission timing of the first pilot subcarrier and the transmission timing of the second pilot subcarrier; and transmission means for OFDM-modulating and transmitting the pilot signals, the macro-diversity signals and the non-macro-diversity signal, through the subcarriers to which the signals are allocated by the first allocation means, the second allocation means and the third allocation means; and wherein the receiver comprises: reception means for receiving the pilot signals, the macro-diversity signals and the non-macro-diversity signal, through the subcarriers transmitted by the transmission means; first estimation means for conducting channel estimation of the first data subcarrier in accordance with the pilot signal of the first pilot subcarrier received by the reception means, and for conducting channel estimation of the second data subcarrier in accordance with the pilot signal of the second pilot subcarrier received by the reception means; and second estimation means for conducting channel estimation of the third data subcarrier in accordance with the pilot signal of the first pilot subcarrier received by the reception means and the pilot signal of the second pilot subcarrier received by the reception means.