Patent ID: 8073385

Claim:
A wireless repeater, comprising: an input antenna for receiving an input signal; an output antenna for outputting an amplified signal; an amplifier for amplifying the received input signal and providing the output amplified signal to the output antenna; a band filter for limiting the input signal to an operational frequency band of the repeater; a sub-band filter for limiting the output of the band filter to one or more sub-bands within the operational frequency band of the repeater; and a digital feedback path coupled to the output of the sub-band filter and including a digital signal processor for adaptively canceling an echo between the output antenna and the input antenna by implementing an adaptive algorithm based on cross and autocorrelation measurements obtained from the power spectrum of a signal representing the digital output of the repeater and the cross spectrum of the same repeater digital output signal with the repeater input signal after echo cancellation, where the cross and power spectra are normalized by the power spectrum.