Patent ID: 7580484

Claim:
An Orthogonal Frequency Division Multiplexing (OFDM) demodulator for demodulating an OFDM signal, an OFDM symbol defining a transmission unit of the OFDM signal being produced by dividing data streams into a plurality of carriers which are within a predetermined bandwidth and which are modulated with orthogonal modulation and discretely inserting a synchronizing signal with known power and known phase in a predetermined carrier, said OFDM demodulator comprising: transformation means for transforming said OFDM signal into a data signal comprising a carrier of said OFDM symbol; extraction means for extracting said synchronizing signal from said data signal transformed by said transformation means; a plurality of time axis filtration means for predicting carrier correction values based on said synchronizing signal contained within said OFDM symbol which is separated in a time axis direction relative to said carrier regarded as a carrier signal segment for correction and for performing correction in a time axis direction of said carrier signal segment for correction; weighting composite output means for weighting and performing composite output relative to each of said carrier correction values predicted by said plurality of time axis filtration means; detection means for detecting an amount of time variation in said carrier correction values in said time axis direction based on said synchronizing signal in a plurality of different OFDM symbols; selection means for selecting at least one of said carrier correction values predicted by at least one of said plurality of time axis filtration means among said carrier correction values predicted by said plurality of time axis filtration means, or a weighting composite value relative to each of said carrier correction values predicted by said plurality of time axis filtration means, based on a detection result of said detection means; frequency axis prediction means for predicting a correction value in a carrier frequency axis direction of said carrier regarded as said carrier signal segment for correction based on a result selected by said selection means; and waveform equivalence means for performing waveform equivalence of said data signal transformed by said transformation means using a result predicted by said frequency axis prediction means.