Abstract: A system and method for detecting a synchronization (sync) signal in a communication signal are disclosed. A received communication signal is stored in a memory and portions thereof are read from the memory and monitored to detect the sync signal. When a detected sync signal is determined to be invalid, previously read portions of the received communication signal, preferably beginning at a portion of the received signal immediately after a start of the detected sync signal, are again read and monitored to detect the sync signal. Such reading and monitoring of previously read portions of a received signal provide for recovery from so-called false triggering based on invalid sync signals.

Abstract: A system and method is described for establishing a homogenized communications infrastructure that enables a variety of disparate communication devices to communicate transparently with each other over a computer data network. The system and method allow for such communications to take place by converting all communications from all participants in the form of audio, video, textual, and binary data messages into discrete data units that are carried over a computer data network. These communications are propagated to other participants by relay to their particular devices in such a way that individual participants are insulated from the type and implementation of all other participants' devices.

Abstract: An echo canceler has an adaptive filter that generates an echo replica signal from a far-end signal. The filter coefficients of the adaptive filter are updated according to a residual error signal, which is obtained by subtracting the echo replica signal from a near-end signal to cancel echo. A background noise estimator estimates the near-end background noise power level from the residual error signal. A step size calculator uses the estimated near-end background noise power in determining the step size of the adaptive updating of the filter coefficients. When the estimated near-end background noise level is high, a small step size is used, which improves echo cancellation under these conditions. When the estimated near-end background noise level is low, a larger step size is used to permit rapid convergence of the filter coefficients.

Abstract: The present invention provides a technique for automatically establishing a virtual circuit from one edge device to another through a core network. The virtual circuit may comprise one or more pseudowire segments. These pseudowire segments extend between adjacent edge and core devices within the core network. Pseudowire segments through the core network are automatically stitched together as a setup message is forwarded from a first edge device to a second edge device through the core network. A virtual circuit is established in one direction, and packets are forwarded in an opposite direction. With the present invention, a virtual circuit comprising any number of pseudowire segments, as well as two attachment circuits, may be established in an automatic and efficient manner upon being initiated by the first edge device.

Abstract: The present invention discloses a method for improving channel estimation in a communications network.

Abstract: Embodiments related to echo compensation have been described and depicted.

Abstract: Disclosed is a non-linear echo canceller and method for cancelling echo during full duplex communication in a hands free communication system. An input signal from a far-end talker and an input signal from the output from an echo canceller are received. K spectral subbands are created for each input signal. The spectral echo residual power at each subband is estimated and compared to a clean signal power to calculate a signal to echo ratio. Gains are calculated based on each calculated ratio and non-linear echo is cancelled based on the calculated gains.

Abstract: A digital controller includes a sampling component that samples an output signal from a system and an input signal to the system at a first sampling rate, which is at least equal to a predetermined operating rate. An input parameter obtaining component obtains a plurality of input parameters from the samples at the first sampling rate. A decimator component generates subsampled values for the plurality of input parameters at a second sampling rate, which is slower than the first sampling rate. An adaptive plant estimator component generates a model of the system based on the subsampled values. A compensator design component determines compensator parameters based on the model. The compensator parameters reflect changes in the system and are sampled at the second sampling rate. A feedback compensator adjusts the input signal to the system based on the compensator parameters.

Abstract: An apparatus for channel interference cancellation includes a first interference-cancellation module and a first cancellation-signal generating circuit. The first interference-cancellation module comprises a first processing circuit including a grouping circuit and a first transforming circuit. The grouping circuit divides received data into a plurality of groups of first sub-data. The first transforming circuit sequentially transforms the groups of first sub-data from a first domain to a second domain to generate a plurality of groups of first transformed sub-data. The first cancellation-signal generating circuit comprises a delay unit, a first processing unit and a second processing unit. The delay unit sequentially delays the groups of first transformed sub-data to generate a plurality of groups of delayed sub-data. The first and the second processing unit output a first and a second processed signal according to the groups of first transformed sub-data and the groups of delayed sub-data respectively.

Abstract: A system and method for designing a full duplex communications transceiver to enable a reduction in isolation between a transmit signal and a receive signal at a diplexer is disclosed. An RFE transmit filter attenuation level can be determined to be sufficient to attenuate a noise power of the transmitter below a thermal noise floor of the power amplifier. A minimum diplexer transmit filter attenuation level can be calculated to attenuate noise power output from the power amplifier in the receive band to a level below a noise floor of the receiver.

Abstract: A network apparatus with a plurality of transport ports and a shared coefficient update processor is proposed. Each of the plurality of transport ports includes a PHY module. The coefficient update processor is coupled to each PHY module and is shared by the plurality of transport ports. The coefficient update processor decides coefficients of each PHY module. The coefficient update processor is dedicated to one of the plurality of transport ports for use in a period of time.

Abstract: A method and system are described for canceling an echo signal in analog domain with adaptive filters working in digital domain. In one embodiment a system includes an analog-to-digital converter (ADC) sampling at two different phases to generate a first error signal and a second error signal having different phases. The ADC operates at a frequency significantly lower than the frequency at which the individual filters run. The first adaptive filter unit and a second adaptive filter unit are independently trained with the first and second error signals. respectively. The first and second adaptive filter units generate echo estimate signals used to cancel the echo signal.

Abstract: An echo canceller (106) can include a first multi-band filter (152) which receives a first input signal (108) and generates a first plurality of sub-band signals (110, 111, 112), and a second multi-band filter (154) which receives a second input signal (122) and generates a second plurality of sub-band signals (156, 157, 158). The echo canceller also can include a plurality of double talk detectors (168, 169, 170) that each generate a double talk flag (182, 183, 184) based on at least a respective one of the first sub-band signals and a respective one of the second sub-band signals.

Abstract: A method and system are described for canceling an echo signal in analog domain with adaptive filters working in digital domain. In one embodiment, a system includes an analog-to-digital converter (ADC) sampling at two different phases to generate a first error signal and a second error signal having different phases. The ADC operates at a frequency significantly lower than the frequency at which the individual filters run. The first adaptive filter unit and a second adaptive filter unit are independently trained with the first and second error signals, respectively. The first and second adaptive filter units generate echo estimate signals used to cancel the echo signal.

Abstract: Digital signal processing based methods and systems for receiving electrical and/or optical data signals include electrical receivers, optical receivers, parallel receivers, multi-channel receivers, timing recovery schemes, and, without limitation, equalization schemes. The present invention is implemented as a single path receiver. Alternatively, the present invention is implemented as a multi-path parallel receiver in which an analog-to-digital converter (“ADC”) and/or a digital signal processor (“DSP”) are implemented with parallel paths that operate at lower rates than the received data signal.

Abstract: The invention provides a full-duplex communication device. In one embodiment, the full-duplex communication device comprises a first adaptive filter, a second adaptive filter, a channel decoupling module, and a frequency processing module. The first adaptive filter having a first tap length filters out echoes of a far-end talker from a first near-end signal carrying voices of a near-end talker according to a far-end signal carrying voices of the far-end talker to obtain a second near-end signal. The second adaptive filter having a second tap length less than the first tap length filters out echoes of the far-end talker from the first near-end signal according to the far-end signal to obtain a third near-end signal. The channel decoupling module processes the second near-end signal to generate a fourth near-end signal and subtracts the second near-end signal from the third near-end signal to obtain a fifth near-end signal.

Abstract: A frequency-shift keying (FSK) signal detector includes a binarizing circuit for receiving an FSK signal and expressing amplitude of the FSK signal in binary; a correlator for receiving the FSK signal expressed in binary and acquiring a correlation of the FSK signal; and an arithmetic unit for performing an arithmetic operation on the output of the correlator to detect and output the FSK signal. The correlator includes plural stages of shift register for sequentially shifting the FSK signal in response to a clock signal; a correlation filter for obtaining the correlation by a correlation signal sequence and a window function signal sequence which obtain a correlation value at one of two frequency components generated by frequency-shift keying; and another correlation filter for obtaining the correlation by a correlation signal sequence and a window function signal sequence which obtain a correlation value at the other of the two frequency components.

Abstract: A system and method facilitating acoustic echo cancellation convergence detection is provided. The invention includes an acoustic echo cancellation convergence detector having a center clipping component, a convergence calculator, a convergence filter and a convergence statistic component. The invention provides for the acoustic echo cancellation convergence detector to provide an output regarding convergence of an adaptive filter based, at least in part, upon a filtered convergence statistic. Optionally, the acoustic echo cancellation convergence detector can provide an output associated with convergence history.

Abstract: The present disclosure relates generally to systems and methods for transmitter leak-over cancellation. In one example, a method includes transmitting a signal via a transmit chain in a wireless device, where a portion of the signal leaks over into a receive chain of the wireless device and generates higher order products that interfere with a signal being received by the wireless device. A portion of the signal from the transmit chain is diverted into cancellation circuitry coupled to the receive chain prior to a location in the transmit chain where leak-over occurs, and an amplitude and phase of the portion is manipulated. The manipulated portion is combined with the received signal and other portion to at least partially cancel interference caused by the portion leaking over into the receive chain.

Abstract: A demodulator cancels out the echo signal properties in the received signal to generate a primary signal, and cancels out the primary signal properties in the received signal to generate a separate echo signal. In addition, the demodulator may combine the primary signal and the echo signal in a comparison/combination operation to generate a third combined signal. Error correction operations may then be performed on all three of the primary signal, echo signal and combined signal, with the results of those error correction operations being used to select which of the three signals will serve as the transport stream.

Abstract: Methods and apparatus for canceling distortion in full-duplex transceivers are disclosed. Some example methods to reduce distortion in a full-duplex transceiver include generating a first digital signal, generating a first analog signal based on the first digital signal for transmission over a full-duplex channel, receiving a second analog signal via the full-duplex channel, and generating a second digital signal based on the second analog signal, wherein the second digital signal includes coupling distortion based on the first analog signal. The example methods further include generating an adaptive filter signal based on the first digital signal, and reducing the coupling distortion from the second digital signal by subtracting the adaptive filter signal from the second digital signal.

Abstract: A method and apparatus for reducing crosstalk in a multi-channel communication system is disclosed. In one embodiment, outgoing signals in a multi-channel environment are manipulated into a transform domain, such as the frequency domain. Thereafter, the signals may be combined and modified based on a weighting variable to create a cancellation signal. Combined processing greatly reduces system complexity and increases processing speed. After processing in the transform domain, the cancellation signal undergoes further processing to return the cancellation signal into the time domain. The cancellation signal may then be combined with received signals to cancel crosstalk or echo. A method and apparatus for crosstalk cancellation in the analog domain and digital domain is also disclosed.

Abstract: Provided is a voice signal detection system and method, which extracts peaks from an input signal, compares a voltage level of each of the extracted peaks to a pre-set threshold voltage level, converts the comparison result to a binary sequence, determines the length of a test window to examine the converted binary sequence, detects micro events in a test window length unit, links the detected micro events, and determines a starting and ending point of a voice signal by detecting a starting and ending point of the linked micro events. Accordingly, by extracting and analyzing peak characteristic information of a time axis, voice can be detected with minimal calculation and noise interference.

Abstract: A noise filter, used for a digital signal, configuring an [N?1]-stage filter by connecting the N-number of flip flops in series comprises a selection unit for outputting a filter output signal by selecting one of signals filtered by one to (N?1) stages based on a selection signals; and a wave form check unit for making the selection unit change a selection thereby by changing a value of the selection signal based on a pulse width on the filter output signal which is output from the selection unit.

Abstract: During communication over the network, periods of silence may exist. During these periods, the system may enable a user at a user terminal to select a type of comfort signal to be played. The system may monitor transmission to detect periods of silence. The system may adapt the monitored transmission by adding the selected comfort signal during the periods of silence, as background noise, or during periods of silence and as background noise.

Abstract: An apparatus and method for detecting a voice activity period. The apparatus for detecting a voice activity period includes a domain conversion module that converts an input signal into a frequency domain signal in the unit of a frame obtained by dividing the input signal at predetermined intervals, a subtracted-spectrum-generation module that generates a spectral subtraction signal which is obtained by subtracting a predetermined noise spectrum from the converted frequency domain signal, a modeling module that applies the spectral subtraction signal to a predetermined probability distribution model, and a speech-detection module that determines whether a speech signal is present in a current frame through a probability distribution calculated by the modeling module.

Abstract: A system and method for designing a full duplex communications transceiver to enable a reduction in isolation between a transmit signal and a receive signal at a diplexer is disclosed. An RFE transmit filter attenuation level can be determined to be sufficient to attenuate a noise power of the transmitter below a thermal noise floor of the power amplifier. A minimum diplexer transmit filter attenuation level can be calculated to attenuate noise power output from the power amplifier in the receive band to a level below a noise floor of the receiver.

Abstract: During communication over the network, periods of silence may exist. The system may enable a user at a user terminal to determine one or more events that trigger the addition of a comfort signal. The system may monitor packet transmission to isolate the one or more events. The system may selectively add the comfort signal to the transmission in reaction to the triggering of the one or more events. The comfort signal may be added during periods of silence, as background noise, or during periods of silence and as background noise.

Abstract: The present disclosure relates generally to systems and methods for transmitter leak-over cancellation. In one example, a method includes transmitting a signal via a transmit chain in a wireless device, where a portion of the signal leaks over into a receive chain of the wireless device. A portion of the signal is diverted from the transmit chain into cancellation circuitry coupled to the receive chain to manipulate an amplitude and phase of the portion before combining the manipulated portion with the signal and other portion to at least partially cancel interference caused by the leak-over portion. After downconverting, a remainder portion is filtered from the received signal. A power level of the remainder portion is detected and compared to a threshold value. An amplitude and phase configuration of the cancellation circuitry is modified based on a result of comparing the power level to the threshold value.

Abstract: A hardware apparatus (10) for conditioning pilot symbols for channel estimation in a mobile radio comprises a time-division multiplexed low-pass filter unit for filtering the received pilot symbols. The time-division multiplexed low-pass filter unit comprises, between its input and its output, a feedback path which can be switched in and which can be used to implement a plurality of filter stages in a time-division multiplexed arrangement.

Abstract: During communication over the network, periods of silence may exist. During these periods, the system may enable a user at a user terminal to define characteristics of a comfort signal. The system may monitor transmission to detect periods of silence. The system may adapt the monitored transmission by adding the defined comfort signal during the periods of silence, as background noise, or during periods of silence and as background noise.

Abstract: A method and apparatus for dynamically inserting gain in an adaptive filter is taught. This selective insertion of gain may be used to allow an adaptive filter to converge more quickly and/or to overcome inherent limitations of the adaptive filter. An echo canceller (e.g. 20 and 22 in FIG. 1) is just one possible use for an adaptive filter having a shorter convergence time. However, virtually all uses of an adaptive filter can benefit from a shorter convergence time and/or improved filtering performance.

Abstract: A method of communicating at least one data burst using an assigned radio configuration. The assigned radio configuration is chosen from one of at least two radio configurations by examining which radio configuration supports a higher data transmission rate. This examination is determined by calculating the data transmission rate for the data burst(s) base on a power level and Walsh code for each of the radio configurations.

Abstract: A method and system receives a far-end signal and determines whether the far-end signal is representative of a modulated signal. The method and system also receives a near-end signal and determines whether the near-end signal is representative of a modulated signal. Predetermined characteristics of the near and far-end signals are determined as is whether the echo canceller will converge for the far-end signal. The operation of the echo canceller is controlled in response to the determination of the predetermined conditions and in response the determination of whether the far-end and near-end signals are modulated signals.

Abstract: A network apparatus for eliminating interference between transport ports includes a plurality of transport ports and at least one alien NEXT canceller. The alien NEXT canceller is coupled to a designated transport port of the plurality of transport ports for eliminating NEXT interference from other transport ports of the plurality of transport ports. The alien NEXT canceller operates in a time domain or a frequency domain. In one exemplary embodiment, the network apparatus is a switch.

Abstract: The invention relates to an apparatus for preprocessing of pilot symbols for channel estimation. The pilot symbols are transmitted from a base station and are received by a mobile radio, and are available in the mobile radio. The apparatus includes a low-pass filter apparatus for filtering the received pilot symbols, with a setting of the low-pass filter apparatus depending on the relative speed of the mobile radio with respect to the base station.

Abstract: A method and apparatus are disclosed for reducing cross-talk in an unbalanced channel with a reduced number of redundancies. A cross-talk canceller is disclosed that uses a multi-dimensional finite impulse response (FIR) filter to process a received signal. Redundancies are reduced or even removed entirely by processing the signals received on each twisted pair in a vector form, using multi-dimensional finite impulse response filters. The signals received by a transceiver on each twisted pair are represented in a vector form so that the signals received on each twisted pair, and the cross-talk effect that each signal has on one another, can be performed collectively. A multi-dimensional cross-talk canceller processes a vector representation of the corresponding signals transmitted by the transceiver on each twisted pair.

Abstract: A method for receiving a frame in a high data throughput wireless local area network begins by receiving a preamble of the frame via a channel in accordance with a default receiver filter mask. The processing continues by validating the preamble. The processing continues by, when the preamble is validated, interpreting the preamble to determine a high data throughput channel configuration. The processing continues by reconfiguring the default receiver filter mask in accordance with the high data throughput channel configuration to produce a reconfigured receiver filter mask. The processing continues by receiving a data segment of the frame in accordance with the reconfigured receiver filter mask.

Abstract: The present invention relates to a method and apparatus for detecting voice activity in a communication signal, wherein filter means are provided for estimating or suppressing an offset component of the level of the communication signal. A filter parameter is controlled based on the output of the filter means. Furthermore, the estimation or suppression of the offset component is limited in response to the output of the filter means. The filter means may be based on a non-linear adaptive notch level filter or a noise floor tracking filter. Thereby, the tracking behavior of noise floor estimation to sudden rises in noise floor can be improved and the voice activity detection can work efficiently over a wide dynamic range.

Abstract: The invention provides a full-duplex communication device. In one embodiment, the full-duplex communication device comprises a first adaptive filter, a second adaptive filter, a channel decoupling module, and a frequency processing module. The first adaptive filter having a first tap length filters out echoes of a far-end talker from a first near-end signal carrying voices of a near-end talker according to a far-end signal carrying voices of the far-end talker to obtain a second near-end signal. The second adaptive filter having a second tap length less than the first tap length filters out echoes of the far-end talker from the first near-end signal according to the far-end signal to obtain a third near-end signal. The channel decoupling module processes the second near-end signal to generate a fourth near-end signal and subtracts the second near-end signal from the third near-end signal to obtain a fifth near-end signal.

Abstract: A method and apparatus are provided for adapting a pilot filter based on the velocity of a wireless communication device (WCD) in relation to a wireless network infrastructure. The pilot filter is adapted by determining pilot coefficients for the pilot filter based on the WCD velocity. The pilot filter may be located in the WCD, or in the network infrastructure, or in both.

Abstract: A wireless terminal for use in the transmitting and receiving frequency bands of a frequency duplex system comprises transmitting and receiving stages (Tx, Rx) and signal propagating means (22, 24, 26) coupled to the transmitting and receiving stages. The signal propagating means comprises a narrow band antenna structure (24), such as a Planar Inverted-F Antenna (PIFA), having sufficient bandwidth to cover the larger one of the transmitting and receiving frequency bands and a BAW receiving filter (26) and a BAW transmitting filter (22) coupled by respective feeds to the antenna structure (24). The filters (22, 26) enable the antenna structure to have a small volume and be reusable at different FDD frequencies.

Abstract: A communication end device of a two-way communication system is shown. The device includes an audio signal capture device for capturing local audio to be transmitted to another end device, an audio signal rendering device for playing remote audio received from the other end device, and buffers for buffering the captured and rendered audio signals. The device also includes an audio echo canceller operating to predict echo from the rendered audio signal at a calculated relative offset in the captured audio signal based on an adaptive filter, and subtract the predicted echo from the signal transmitted to the other end device The calculated relative offset that is used by the audio echo canceller for a current signal sample is adjusted if a difference between it and an adjusted relative offset of a preceding sample exceeds a threshold value.

Abstract: Embodiments of an audio communication device and methods for reducing echoes are generally described herein. Other embodiments may be described and claimed. In some embodiments, echo-reduction circuitry may insert a training signal into digital audio signals at or below a noise floor and in a non-audible portion of the frequency spectrum based on a spectral mask. The training signal may be generated from a spectrum estimate and a training sequence. An adaptive filter may generate an echo-cancellation signal using filter coefficients generated from the training sequence and return-path signals. The echo-cancellation signal may remove echo signals from the return-path signals.

Abstract: Embodiments of a multi-channel audio communication device and methods for reducing echoes are generally described herein. Other embodiments may be described and claimed. In some embodiments, echo-reduction circuitry may insert training signals into digital audio signals at or below a noise floor and in a non-audible portion of the frequency spectrum based on a spectral mask. Training signals may be generated from spectrum estimates and training sequences. An adaptive filter may generate echo-cancellation signals using filter coefficients generated fawn the training sequences and return-path signals. The echo cancellation signals may remove echo signals from the return-path signals.

Abstract: 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.

Abstract: A method and apparatus for reducing crosstalk in a multi-channel communication system is disclosed. In one embodiment, outgoing signals in a multi-channel environment are manipulated into a transform domain, such as the frequency domain. Thereafter, the signals may be combined and modified based on a weighting variable to create a cancellation signal. Combined processing greatly reduces system complexity and increases processing speed. After processing in the transform domain, the cancellation signal undergoes further processing to return the cancellation signal into the time domain. The cancellation signal may then be combined with received signals to cancel crosstalk or echo. A method and apparatus for crosstalk cancellation in the analog domain and digital domain are also disclosed.

Abstract: The present invention provides a method for hardware reduction in the echo canceller and the near-end crosstalk canceller. The method applies an N (N is a positive integer) times divide frequency sampling operation onto the input data list of the echo canceller first (and the near-end crosstalk canceller). Then, it applies an N times multiply frequency sampling operation onto the output data list of the echo canceller (and the near-end crosstalk canceller) to generate a multiplied frequency data list. Afterwards, a low pass filter operation is applied to the multiplied frequency data list to generate a low pass data list to eliminate the echo signal (and the near-end crosstalk signal). The present invention reduces the number of the taps in the echo canceller and the near-end crosstalk canceller by using the digital signal process technique. Therefore, the area of the whole communication IC occupied by the echo canceller and the near-end crosstalk canceller can be reduced.

Abstract: A duplexer includes an input/output line, a receive segment and a transmit segment. The transmit segment is connected to the input/output line. The receive segment includes a balun and a differential filter. The balun includes a first output, a second output, a first transmission line and a second transmission line. The first transmission line is connected between the input/output line and the first output. The second transmission line is connected between the input/output line and the second output. The differential filter is connected to the first output and the second output. The differential filter shorts the first output and the second output at transmit band frequencies of the duplexer.

Abstract: A linear/non-linear adaptive filter for transforming an input signal to an output signal. The present invention also includes a novel GSPT LMS algorithm for significantly reducing complexity. The adaptive filter includes a coefficient updater that can execute a Carry-in operation or a Borrow-in operation to adaptively adjust a filtering coefficient according to whether an updating term signal is a Carry-in signal or a Borrow-in signal.