Patent ID: 7298785

Claim:
A multicarrier demodulation method for receiving a multicarrier modulated signal which consists of N subcarriers containing N-L (L<N) nullcarriers as subcarriers and in which an effective symbol has a length T, and a frequency interval between two adjacent subcarriers of the N subcarriers is 1/T, and for demodulating the received signal to respective subcarriers, the method comprising: a step of estimating an excess delay of a delayed wave, and deciding a part of the symbol regarded as a to-be-used symbol part, on the basis of the estimated excess delay, where a length of the decided part of the symbol is TM/N (M<N) within the effective symbol length T and the part of the symbol is decided so as not to contain a part of the symbol suffering from a waveform distortion caused by the delayed wave; a step of decomposing a complex digital signal which is quadrature-detected at sampling intervals T/N into L subcarriers by use of M samples of the signal within the to-be-used symbol part by means of a matched filter; and one or a plurality of interference component removal steps of deciding L symbols tentatively from signals of the L subcarriers, obtaining interference components by use of the L tentative symbol decisions, that are contained in each of the signals of the L subcarriers separated by means of the matched filter and caused by other subcarriers, and subtracting the obtained interference components contained in each of the signals of the L subcarriers from the signals of the L subcarriers separated by means of the matched filter, to thereby obtain more reliable signals of the L subcarriers.