Patent ID: 8411768

Claim:
A communication system comprising: a transmission apparatus comprising: a generation unit configured to generate an orthogonal frequency division multiplexing (OFDM) symbol in which a modulation parameter at a time of data transmission is arranged in a subcarrier of a direct current component; an adjustment symbol addition unit configured to add an adjustment symbol having a time length based on fluctuations in a clock signal to a rear end of the OFDM symbol; and a transmission unit configured to transmit a transmission frame including the OFDM symbol and the adjustment symbol; and a receiving apparatus comprising: a calculation unit configured to calculate an average value within an effective symbol period in the OFDM symbol included in the transmission frame received by the receiving apparatus; an extraction unit configured to extract the modulation parameter arranged in the subcarrier of the direct current component based on the calculated average value; and a demodulation unit configured to perform OFDM demodulation processing using the modulation parameter extracted by the extraction unit, wherein the OFDM symbol includes an effective symbol and a guard interval, and the modulation parameter includes timing information for the effective symbol.