Lucent Technologies Inc.

Alcatel Lucent

Alcatel-Lucent USA Inc.

At&t Bell Laboratories

Agere Systems Inc.

Other

Dennis Raymond Morgan

Zhengxiang Ma

Ilija Hadzic

Jacob Benesty

Gary Wayne Elko

James Edward West

Michael George Zierdt

Robert A Kubli

Lei Ding

Zulfiquar Sayeed

Jaehyeong Kim

Walter Honcharenko

Alf Neustadt

Man Mohan Sondhi

Richard Thomas Aiken

Munawar Hussein Kermalli

Michael M Fitelson

James C Thi

Phillip L De Leon, Ii

Joseph Lindley Hall, Ii

A method and an apparatus for using a plurality of antennas to equalize a composite propagation channel of a wideband wireless communication is provided. The method comprises adjusting a corresponding weight associated with at least two of the plurality of antennas to obtain a channel response from the plurality of antennas over a composite propagation channel. The method further comprises equalizing the channel response of the composite propagation channel over a given bandwidth based on the corresponding weights for the wireless communication over a wideband frequency range. By adjusting a complex weight associated with each of the set of transmit antennas, a wireless communication system may obtain a channel response from the plurality of antennas over the composite propagation channel. In this way, the wireless communication system may combine multiple antenna signals from the set of transmit antennas with the complex weights to provide an overall transfer function that is substantially flat over a given bandwidth.

Composite channel equalization of a wideband wireless communication system

A signal coding technique for switching amplifiers includes quantizing the amplitude A(t) of an input signal to produce a time series &#xc2;(t) having M levels; modulating a clock signal in response to &#xc2;(t), thereby to produce a control signal; switching among at least three different power supply output levels in response to the control signal, thereby to generate an output pulse stream; and filtering the output pulse stream to produce an output signal for transmission.

Method and apparatus of switched amplification having improved efficiency

An endpoint or other communication device of a communication system includes a clock recovery loop having a phase error estimator. The communication device is operative as a slave device relative to another communication device that is operative as a master device. The clock recovery loop is configured to control a slave clock of the slave device responsive to a phase error estimate generated by the phase error estimator so as to synchronize the slave clock with a master clock of the master device. The phase error estimator comprises a plurality of filters each configured to generate a different estimate of master clock phase using at least a subset of a plurality of packets received from the master device, and control logic for adaptively selecting at least a particular one of the plurality of filters for use in generating the phase error estimate to be processed in the clock recovery loop.

Frequency synchronization using clock recovery loop with adaptive packet filtering

An endpoint or other communication device of a communication system includes a clock recovery module. The communication device is operative as a slave device relative to another communication device that is operative as a master device. The clock recovery module comprises a clock recovery loop configured to control a slave clock frequency of the slave device so as to synchronize the slave clock frequency with a master clock frequency of the master device. The clock recovery loop utilizes a frequency error estimator implemented as a maximum-likelihood estimator with slope fitting based on a sequence of arrival timestamps, and a loop filter implemented as a series combination of an adaptive-bandwidth filter and a proportional-integral controller. The clock recovery module may further comprise a discontinuity detector configured to detect a discontinuity in delays of respective timing messages, and a loop controller operative to place the clock recovery loop in a particular state responsive to detection of the discontinuity.

Method, apparatus and system for frequency synchronization between devices communicating over a packet network

An endpoint or other communication device of a communication system includes a clock recovery module. The communication device is operative as a slave device relative to another communication device that is operative as a master device. The clock recovery module comprises a clock recovery loop configured to control a slave clock frequency of the slave device so as to synchronize the slave clock frequency with a master clock frequency of the master device. The clock recovery loop comprises a primary loop having a first frequency error estimator for generating a first estimate of error between the master and slave clock frequencies, a second frequency error estimator outside of the primary loop for generating a second estimate of error between the master and slave clock frequencies, and an accumulator coupled between the second frequency error estimator and the primary loop. The second estimate is controllably injected into the primary loop via the accumulator.

Frequency synchronization using first and second frequency error estimators

The present invention relates to a method of wideband RF detection. The method may include transmitting a signal from a plurality of transmit positions along a drive path. Reflections of the transmitted signal are received at a plurality of receive positions along the drive path. A signature is formed based on arrival angles of the reflections at each of the receive positions. The signature includes the arrival angles of the reflections at each of the receive positions with respect to a distance along the drive path of a corresponding transmit position and a corresponding receive position of each of the reflections.

Wideband RF detection

A repeater and methods thereof are provided. The example repeater first receives a donor signal (e.g., from a base station for repeating in a downlink direction, from a mobile station for repeating in an uplink direction, etc.) and a transmitted version of an internally generated pilot signal. The repeater configures an adaptive filter signal to cancel the received transmitted version of the internally generated pilot signal. In an example, the first receiving and configuring steps may be performed during a first mode of operation (e.g., a 'training' mode). The repeater second receives the donor signal and a retransmitted version of the donor signal (e.g., retransmitted from the repeater). The repeater cancels the retransmitted donor signal based on the configured adaptive filter signal.

Repeater for providing coverage within a wireless communications network and methods thereof

A Doppler radar signal processing system and method and a Doppler radar employing the system or the method. In one embodiment, the system includes: (1) an input configured to receive at least one radar output signal representing a reflected Doppler radar signal, (2) signal processing circuitry coupled to the input and configured to produce an arc-length cardiopulmonary signal from the at least one radar output signal and employ a respiration fundamental frequency estimate to extract a heart rate signal from the arc-length cardiopulmonary signal and (3) an output coupled to the signal processing circuitry and configured to provide the heart rate signal.

Doppler radar cardiopulmonary sensor and signal processing system and method for use therewith

The invention is a method and apparatus for frequency-domain adaptive filtering that has broad applications such as to equalizers, but is particularly suitable for use in acoustic echo cancellation circuits for stereophonic and other multiple channel teleconferencing systems. The method and apparatus utilizes a frequency-domain recursive least squares criterion that minimizes the error signal in the frequency-domain. In order to reduce the complexity of the algorithm, a constraint is removed resulting in an unconstrained frequency-domain recursive least mean squares method and apparatus. A method and apparatus for selecting an optimal adaptation step for the UFLMS is disclosed. The method and apparatus is generalized to the multiple channel case and exploits the cross-power spectra among all of the channels.

Multi-channel frequency-domain adaptive filter method and apparatus

In a transmitter, an upconverter converts a lower frequency signal to a higher frequency signal. Prior to the upconversion, a compensator compensates for at least gain/phase distortion that will be introduced into the lower frequency signal by at least the upconverter.

Frequency based modulator compensation

A signal is predistorted by producing a set of sample values, each of at least a subset of which is dependent on (i) at least one of a plurality of past time spaced input samples and (ii) a current time spaced input sample, and independent of any other time spaced input sample, and combining the sample values to produce the predistorted signal. Predistortion circuitry for generating the predistorted signal may be implemented using multiple predistortion core circuits, with each of the predistortion core circuits receiving a data input and an index input associated with a particular input sample and generating a corresponding data output. The data outputs of the predistortion core circuits correspond generally to sample values. The predistortion circuitry may also include at least one memory finite impulse response (FIR) filter which processes one or more input samples in conjunction with the production of the sample values.

System and method for predistorting a signal using current and past signal samples

A signal is predistorted by producing a first set of sample values using a first predistortion technique, producing a second set of sample values using a second predistortion technique different than the first predistortion technique, and combining the first and second sets of sample values to produce a predistorted signal. At least one of the first and second predistortion techniques produce the corresponding set of sample values based at least in part on a plurality of past time spaced input samples relative to a current time spaced input sample. By way of example, the first predistortion technique may be configured to produce sample output values each of which is dependent on one of a plurality of time spaced input samples and independent of any other time spaced input sample, and the second predistortion technique may be configured to produce sample output values each of which is dependent on (i) at least one of a plurality of past time spaced input samples and (ii) a current time spaced input sample, and independent of any other time spaced input sample.

Signal predistortion using a combination of multiple predistortion techniques

A method for processing signals from multiple receiving/transmitting elements that define an array antenna is disclosed. The method includes measuring uplink signals from the elements of the array antenna to form a directional downlink antenna response. A first covariance matrix between pairs of uplink signals is determined for desired signal components of the measured uplink signals. A second covariance matrix is determined for noise and interference components of the measured uplink signals. An antenna processing system computes adaptive weights based on the first covariance matrix, the second covariance matrix and a loading term to in effect form a directional downlink radiation pattern. The loading term represents a balance adjustment between a first performance rating of a particular coverage area versus second performance rating of the wireless communication system. The first performance rating can represent the extent of providing a desired downlink power of a downlink signal to a subscriber station within a particular coverage area such as a sector or cell. The second performance rating can represent the extent of suppressing interference to other subscriber stations in the wireless communication system.

Method and system for adaptive signal processing for an antenna array

A method and apparatus for estimating individual impulse responses for a stereophonic communication system, such as a teleconferencing system, which involves selectively reducing the correlation between the individual channel signals of the stereophonic system. Selective reduction of stereophonic source signal correlation advantageously results in the estimation of individual impulse responses of a receiving room of the stereophonic communication system. The selectively reduced-correlation source signals are provided to conventional adaptive filters and the receiving room loudspeakers. Automatic echo cancellation is performed in a conventional fashion, but on the selectively reduced-correlation source signals. Specifically, selective reduction of source signal correlation between two stereophonic channels of a teleconferencing system is achieved by introducing a small non-linearity into each channel in order to reduce the interchannel coherence. In accordance with certain illustrative embodiments of the present invention, each channel signal has added thereto a non-linear function of the channel signal itself, thereby reducing the interchannel coherence while preserving the quality of the signal. In one particular embodiment, the non-linear function comprises the half-wave rectifier.

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Morristown, NJ, United States of America

Dennis Raymond Morgan