Mitel Networks Corporation

Zarlink Semiconductor Limited

Mitel Knowledge Corporation

Mitel Cloud Services, Inc.

Mitel Corporation

Mitef Networks Corporation

Dieter Schulz

Mirjana Popovic

Renee Johnston

Yonghua Fang

Jan Radecki

Rafik Alphonse Goubran

Paul Andrew Erb

Lee Dilkie

Graham Thompson

Charn Leung (David) Lo

Andrew Wu

Logendra Naidoo

Sonya G Fullarton

Michael Tetelbaum

Edward Peter Gancarcik

Radovan Prodanovic

Jean-Yves Patry

Roger Bastin

Dean Swan

Dennis Deans

Chi Keung Leung

Marco Nasr

Maziar Amiri

Ying Huang

Peter Bohacek

Dave Speirs

Jean-yves Patry

Charn Leung Lo

Sonya Fullarton

A communication system with a noise cancellation (NC) assembly providing adaptive or dynamic noise cancellation. The NC assembly includes a localizer module determining, during a communication session (active speaking or during idle times), a location of the active talker. The NC assembly includes a beam generator forming a beam in the determined direction of the active talker to enhance the active talker speech. Once the NC assembly has determined the position of the active talker, the NC assembly assigns a microphone of the microphone array or generated beam in that active direction to be the 'active signal' source. The NC assembly assigns a second microphone or beam to be the noise source for NC purposes, and this source may be selected to be in acoustic shadow of the first microphone used as the active signal source or may be the farthest away in its position from the active talker's position.

Adaptive noise cancelling for conferencing communication systems

A cloud based echo canceller is set forth for recreating an estimate of a lost packet or data at a server without requiring redundant data over the network or freezing operation of the echo canceller. In an exemplary embodiment, the echo cancelling function is not located in a single device, but is shared between the end-point and a cloud service, where the function of the end-point is to provide a time synchronized copy of the signal from the end-point loudspeaker and the signal received by the end-point microphone. Consequently, the high CPU intensive operations can be offloaded to a server such as a cloud server. In addition, several users can share the echo canceller, thereby reducing the cost of the overall function. According to an additional aspect, a further synchronization block is provided, in the form of a packet estimator, to compensate for packet or data loss in the send direction.

Cloud-based acoustic echo canceller

Technology for dynamic characterization of a communication device is disclosed. One method comprises sending an acoustic characterization excitation signal to be output by an acoustic transducer in the communication device. A received acoustic coupling signal that is received by a microphone of the communication device in response to the output of the acoustic transducer is measured. An acoustic signal conditioning algorithm is applied to at least one of the microphone or the acoustic transducer to reduce an amplitude of the acoustic signal or the received acoustic coupling signal to a level below a selected threshold.

Dynamic characterization of a communication device

An echo canceling system has an adaptive filter connected to an echo source, for canceling echo from an echo path. A fixed echo conditioning filter is connected in series with the adaptive filter, intermediate the echo source and the adaptive filter. The fixed echo conditioning filter cancels the constant part of the echo path using a measured impulse response of the echo path.

System for conditioning echo response of loop start trunk line

A method and apparatus for automatically adjusting volume of an audio signal on a mobile device, comprising playing the audio signal at an initial volume, sampling the audio signal, estimating a transfer function based on an echo path characteristic between the played audio signal and sampled audio signal, selecting a volume policy based on the estimated transfer function, and adjusting the volume of the audio signal in accordance with the selected volume policy.

Method and apparatus for automatically adjusting reminder volume on a mobile communication device

An echo canceller comprising a first adaptive filter having N_long coefficients for converging to an echo path, a non-adaptive filter representing a direct echo path portion captured by the first adaptive filter and having N_short default coefficients, where N_long&#x3e;N_short, for quick convergence of the echo canceller at start-up, wherein the default coefficients are replaced by the first N_short coefficients from the first adaptive filter responsive to an improvement in echo return loss enhancement (ERLE) of the first adaptive filter, a second adaptive filter having N_short default coefficients for modeling the direct echo path and providing an indication of double-talk and echo path changes, decision logic for receiving error signal outputs from the first and second adaptive filters and the non-adaptive filter and in response distinguishing between echo path changes and double-talk, and a non-linear processor for attenuating signals responsive to input from the decision logic.

Method and apparatus for detecting echo path changes in an acoustic echo canceller

The present invention relates generally to tone detection in echo canceling systems, and more particularly to a method of monitoring oscillations of adaptive filter coefficients for narrow band tone detection in echo cancellation systems. The invention is directed at improving communication in a telephone communication network having one or more hybrid connections. A method for detecting continuous tones in an echo canceling system having an adaptive filter is provided. Continuous tones have a deleterious effect on the performance of adaptive filters. In the present invention, the adaptive filter coefficients are monitored. Oscillation of those coefficients indicates continuous tone presence.

Narrow band tone detection in echo canceling system

A system and method for providing early detection of encrypted signals within a secure connection for voice over Internet protocol (VoIP). The system and method includes a non-complex, in-band, and early encryption detector within the voice path. A transmitter sends out a known pattern. Based upon the received pattern, the receiver decides whether its encryption capabilities match up with those of the transmitter. If the capabilities do not match, then the receiver waits for the signalling message for the correct mode of operation. No packets are utilized until the receiver and transmitter encryption capabilities are matched.

Early detection system and method for encrypted signals within packet networks

A method of selecting an optimum impedance for a loop start trunk line, comprising successively applying respective ones of a plurality of impedance settings to the loop start trunk line, for each impedance setting measuring the impulse response of the trans-hybrid echo path by applying audio test signals to obtain a time-domain trans-hybrid transfer function and deriving a frequency-domain spectrum representative of trans-hybrid loss, and then calculating figure of merit of the transfer function based on the power spectrum. Once all impedance settings have been tested, the optimum impedance is selected as the impedance setting associated with the highest calculated figure of merit.

Method for selecting impedance setting for loop start trunk line

A method of determining residue-echo threshold for the trans-hybrid echo path of a loop start (LS) trunk line, comprising the steps of estimating the impulse response of the trans-hybrid echo path, passing a speech-like signal through the LS trunk circuit and collecting the echo signal. The collected echo signal is compared to the convolution of the speech-like signal with the estimated impulse response. The difference between the convolution result and the collected echo signal is the residue echo, which represents the effect of nonlinearity. With different levels of excitation signal, a curve of residue echo power level against input signal level is obtained, and the distortion characteristics are derived from this curve.

Method of measuring distortion and determining residue-echo threshold in loop start trunk circuits

A method is provided for discriminating between the case of a single talker with an acoustic reflection and the case of two talkers, regardless of their power levels. The method is implemented in real time by performing a cross-correlation between pairs of average power signals originating from pairs of beamformers. A detection decision is then made based on the value of the cross correlation and its lag.

Detecting acoustic echoes using microphone arrays

A method of controlling a buffer for reducing jitter in a packet network is provided, with a fast attack and a slow decay time to track delay changes in the network. The principal function of the method for controlling the jitter buffer is to minimize the delay within the buffer and use packet loss compensation in the event that the buffer enters an underflow condition.

Method of dynamic adaptation for jitter buffering in packet networks

A method for detecting echo path changes in an echo canceller using the statistics of the echo canceling behavior (i.e. signal and performance information), to distinguish between new line and double talk conditions. A moving counter is incremented or decremented based on monitored levels of ERL (Echo Return Loss), ERLE (Echo Return Loss Enhancement), noise and signal energies. When the counter reaches a predetermined threshold value indicative of sustained poor echo cancellation performance, a determination is made that there is a probable new line condition (i.e. echo path change). This echo path change information is then passed to the echo canceller to enable re-convergence.

Method for detecting echo path changes in echo cancellers

An echo canceller comprising a digital filter having adaptive coefficients which are updated to simulate an echo response, a temporary register for storing default coefficients, and a controller for monitoring ERLE and in the event the ERLE is greater than a first predetermined threshold then enabling the digital filter and replacing the default coefficients in the temporary register with the adaptive coefficients, and in the event the ERLE is less than a second predetermined threshold then disabling the digital filter and replacing the adaptive coefficients with said the default coefficients from the temporary register.

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Dunrobin, Canada

Dieter Schulz