US 7,406,140 B2 · Wraparound canceller, relay system, and wraparound cancelling method

Abstract

A loop interference canceller that carries out an adaptive operation of responding to time variations of the phase or level of loop interference wave or key station wave at high speed and with high accuracy and reduces the size of an apparatus. The loop interference canceller of the present invention limits the number of data pieces of the transmission path characteristic estimation section, realizes expansion to the entire band not through interpolation but through 0 insertion in a frequency domain and windowing after time domain transformation to reduce the number of data pieces processed and speed up the adaptive operation of the loop interference canceller, and can thereby realize high trackability for time variations of the phase and level of loop interference wave or key station wave, increase the accuracy of processing inside, perform high accuracy cancellation operation, reduce the circuit scale and achieve an advantageous effect of realizing miniaturization of the apparatus.

Claims11

Dependent claims

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.

5 more elements

Dependencies are inferred from the claim text.

Wraparound canceller, relay system, and wraparound cancelling method

Life of this patent

Wraparound canceller, relay system, and wraparound cancelling method

Life of this patent

Abstract

Claims11