Patent ID: 7406140

Claim:
A loop interference canceller for canceling loop interference between transmission/reception antennas when multicarrier signals having reference carriers at regular intervals are relayed at the same frequency for transmission and reception, comprising: a cancellation section that cancels loop interference included in a received signal using a filter for which a factor is set; a transmission path characteristic estimation section that estimates the transmission path characteristic of a signal after said loop interference is canceled; a residual characteristic calculation section that calculates a cancellation residual based on the estimation result of said transmission path estimation section; a 0 insertion section that inserts 0 data for the output of said residual characteristic calculation section; an inverse fast Fourier transform section that transforms the output of said 0 insertion section into a time domain signal; a windowing section that, with respect to the output of said inverse fast Fourier transform section, extracts either a range without the repetitive component of the transmission path characteristic or a range specified by the factor of said filter, whichever is smaller; and an updating section that updates the factor of said filter based on the output of said windowing section.