Patent ID: 7414959

Claim:
Communication device for transmitting and receiving OFDM signals in a wireless communication system, the communication device comprising: antenna means having a plurality of antenna elements for transmitting and receiving said OFDM signals propagated through a plurality of transmission channels in said wireless communication system; means for obtaining channel information concerning attenuation properties of OFDM subcarrier signals transmitted through said plurality of transmission channels; and means for controlling amplitude of said OFDM subcarrier signals in accordance with said channel information, wherein said means for obtaining channel information calculates a magnitude ratio for a limited number of OFDM subcarrier signals received at each of said antenna by comparing a predetermined portion of said limited number of OFDM subcarrier signals with a reference preamble symbol to obtain the attenuation properties of said limited number of OFDM subcarrier signals and then determines the attenuation properties of the rest of OFDM subcarrier signals from said calculated magnitude ratio by estimation.