Patent ID: 6996169
Filing Date: 2006-02-07
Classification: H04L

Abstract:
1. A decision feedback equalizer for suppressing intersymbol interference by feeding back already determined data so as to equalize the waveform distortion of a received radiowave caused by the fading in any radiowave transmission medium of the received radiowave, comprising: impulse response estimating means for estimating an impulse response of the radiowave transmission medium; a first waveform equalizing means for equalizing the waveform of the received wave based on an intersymbol interference component corresponding to more than two symbol-delayed wave and an estimated intersymbol interference component corresponding to one symbol-delayed wave, by using an impulse response from the radiowave transmission medium estimated by said impulse response estimating means, thereby producing an equalized signal, including an intersymbol interference component corresponding to an estimated one symbol-delayed wave, said estimated one symbol-delayed wave being produced by the use of an intersymbol interference component corresponding to more than two symbol-delayed waves; a second waveform equalizing means for equalizing the waveform of said equalized signal including an intersymbol interference component of a one-symbol delayed wave, based on an intersymbol interferences component corresponding to all the one symbol-delayed waves, using an intersymbol interferences component corresponding to all of the symbol-delayed waves, using the impulse response of the radiowave transmission medium estimated by said impulse response estimating means; area determination means for predicting, by determining the extent of a just-preceding symbol of an equalized signal, whether or not there is any determination error due to noise interference, said area determination means functioning to carry out area determination operations for each of said respective equalized signals of a given symbol where any appearance of error in determination is predicted, and for generating three signals that are an equalized signal of the given symbol presumed to be correct in its equalized signals, this determined data as to the given being obtained by demodulating the equalized signal, and a determined piece of data of just preceding symbol being employed for equalizing the just-equalized signal, said determined date of the given symbol being applied to said first waveform equalizing means to produce said estimated intersymbol interference component corresponding to the one-symbol delayed wave; and means for producing the intersymbol interference component corresponding to more than two symbol-delayed waves in order to feed back the intersymbol interference component corresponding to more than two symbol-delayed waves to said first waveform equalizing means.