A method for initialization of a group of customer premises equipment devices (CPEs) during a training that registers capabilities of the CPEs is disclosed, wherein at least one CPE registers late to the training and cannot be registered. The method includes determining capabilities of the CPEs during a joining phase of the training, wherein it is determined whether a CPE device is capable of employing vectoring and placing in a hold status the at least one CPE that registers late by keeping a line active that is coupled to the at least one CPE. The method further includes providing another joining phase after the joining phase to register the at least one CPE that registers late.

Certain aspects of the present disclosure provide techniques for generating and decoding orthogonal frequency division (OFDM) waveforms with peak reduction tones (PRTs) designed to reduce PAPR. By generating PRT tones with a machine learning (e.g., neural network) based encoder and mapping some of the PRT tones to subcarriers used for physical channels or signals, PAPR may be reduced while efficiently using system resources.

A variable update step size is determined in proportion to a magnitude ratio or magnitude difference between a first residual signal and a second residual signal. The first residual signal is obtained by using adaptive filter coefficient sequence, where the adaptive filter coefficient sequence has been obtained in previous operations of the adaptive equalizer. The second residual signal is obtained by using a prior update adaptive filter coefficient sequence, where the prior update adaptive filter coefficient sequence is obtained by performing a coefficient update with an arbitrary prior update step size on the adaptive filter coefficient sequence having been obtained in previous operations of the adaptive equalizer.

The apparatus for reconstructing a desired signal using a full duplex radio (FDR) scheme includes: a digital self-interference cancellation unit configured to output a first digital signal; a demodulator configured to demodulate the first digital signal; a modulator configured to modulate the demodulated first digital signal; an attenuator configured to attenuate the modulated first digital signal by applying an attenuation coefficient to the modulated first digital signal; and an operation unit configured to receive the attenuated first digital signal and the first digital signal, and transmit a residual signal to the digital self-interference cancellation unit, wherein the residual signal is obtained by subtracting the attenuated first digital signal from the first digital signal.

The apparatus for reconstructing a desired signal using a full duplex radio (FDR) scheme includes: a digital self-interference cancellation unit configured to output a first digital signal; a demodulator configured to demodulate the first digital signal; a modulator configured to modulate the demodulated first digital signal; an attenuator configured to attenuate the modulated first digital signal by applying an attenuation coefficient to the modulated first digital signal; and an operation unit configured to receive the attenuated first digital signal and the first digital signal, and transmit a residual signal to the digital self-interference cancellation unit, wherein the residual signal is obtained by subtracting the attenuated first digital signal from the first digital signal.

In example implementations, an apparatus is provided. The apparatus includes an adaptive filter and a double talk detector in communication with the adaptive filter. The adaptive filter is to calculate a transfer function with coefficients for a particular time that is applied to an output signal of a microphone to cancel echoes caused by a reference signal in the output signal of the microphone. The double talk detector is to determine a peak of the coefficients, detect double talk based on a location of the peak of the coefficients, and transmit a pause signal to the adaptive filter in response to detection of the double talk, wherein the pause signal is to pause a calculation of updates to the coefficients by the adaptive filter.

An echo cancellation system that synchronizes output audio data with input audio data in a heterogeneous system. The system may increment a counter as outgoing audio frames are sent to a digital-to-analog converter in a speaker. As incoming audio frames are received by an analog-to-digital converter in a microphone, the system may copy contents of the counter into the incoming audio frames. Based on the contents of the counter, the incoming audio frames may be associated with corresponding outgoing audio frames. After synchronizing the incoming audio frames and the outgoing audio frames, the system may perform Acoustic Echo Cancellation by removing the outgoing audio frames from the incoming audio frames.

From a mixed signal in which a first signal and a second signal are mixed, the second signal is removed at low processing cost and without delay. As a result, an estimated first signal which has low residue of the second signal and low distortion is obtained. An estimated first signal is generated by subtracting a pseudo second signal which is estimated to be mixed in a first mixed signal in which a first signal and a second signal are mixed from the first mixed signal. The pseudo second signal is obtained by a first adaptive filter using a second mixed signal in which the first signal and the second signal are mixed in a different proportion from the first mixed signal. A coefficient update amount of the first adaptive filter is made smaller as compared with a case when the estimated first signal is smaller than the first mixed signal, in case the estimated first signal is larger than the first mixed signal.

From a mixed signal in which a first signal and a second signal are mixed, the second signal is removed at low processing cost and without delay. As a result, an estimated first signal which has low residue of the second signal and low distortion is obtained. An estimated first signal is generated by subtracting a pseudo second signal which is estimated to be mixed in a first mixed signal in which a first signal and a second signal are mixed from the first mixed signal. The pseudo second signal is obtained by a first adaptive filter using a second mixed signal in which the first signal and the second signal are mixed in a different proportion from the first mixed signal. A coefficient update amount of the first adaptive filter is made smaller as compared with a case when the estimated first signal is smaller than the first mixed signal, in case the estimated first signal is larger than the first mixed signal.

An echo removal device comprises: an echo canceller that includes a first delay unit configured to delay a reception signal from a communication counterpart, and that is configured to subtract, from a transmission signal for the communication counterpart, a cancellation signal that is generated based on the delayed reception signal obtained by the first delay unit and property information which simulates a property of an echo path; a second delay unit configured to delay the reception signal by an amount of delay different from an amount of delay of the first delay unit; an echo suppressor configured to receive the delayed reception signal obtained by the second delay unit and an output of the echo canceller; and a delay amount calculator configured to calculate and set the amount of delay of the first delay unit and the amount of delay of the second delay unit based on the property information.