Texas Instruments Corporation

Princeton University

Verticalband, Limited

Mitsubishi Electric Research Laboratories, Inc.

Siemens Corporate Research, Inc.

Envoy Networks, Inc.

Stuart C Schwartz

Triveni N Upadhyay

Tandhoni S Rao

Alexander Flaig

Eilon Riess

Laurence Turner

Samuel Jay MacMullan

H Vincent Poor

John Cangeme

Louis R Brothers, Jr

Les Sabel

John Edward Smee

Jinyun Zhang

Ming Fang

Daqing Gu

Bede Liu

Hisashi Kobayashi

Harold Vincent Poor

Richard D Bang

Keith Michael Andress

Xiaoqiang Ma

Samuel J MacMullen

Juhua Zhu

Vincent H Poor

Samuel J Macmullan

Interference cancellation is performed in a communication system. A signal associated with the users is received to produce a received signal. A set of regeneration factors associated with the users is determined based on the received signal. A frequency range associated with a first user from the users has at least a portion overlapping with at least a portion of a frequency range associated with a second user from the users. A time range associated with the first user from the users has at least a portion overlapping with at least a portion of a time range associated with the second user from the users. A regenerated signal associated with each user from the users is modified based on the determined regenerated factor associated with that user to produce a modified regenerated signal for each user.

Method and apparatus for regenerative based interference cancellation within a communication system

The present invention relates to a method and system for foreground segmentation in which frames of a video sequence are analyzed in the transform domain to determine one or more features. The features are used to model the background. The background can be modeled as a single Gaussian model with a mean and variance of the features. A current frame is segmented by determining if one or more features of the current frame analyzed in the foreground domain satisfy a threshold between the background model. The threshold value can be based on the mean and/or variance of features. During the segmentation, the mean and variance can be updated based on previous corresponding values and current features to adaptively update the background model. In one embodiment, the frames are divided into a plurality of blocks. A transform is used to analyze the blocks in the transform domain. For example, the transform can be a discrete cosine transform (DCT). The features can be a DC feature comprising the DC coefficient and an AC feature comprising a weighted sum of the AC coefficients. The weighted sum is determined with weights which are varied to emphasize different aspects of the present invention. Additional processing steps can be used to remove false positives, handle sudden global illumination changes, handle sudden local illumination changes and remove false negatives.

Method and apparatus for foreground segmentation of video sequences

All practical communication channels impose some type of corruption on received data through inter-symbol interference (ISI). ISI corruption is particularly acute in high-order constellation transmission. Although ISI effects of high-order constellation transmission are very large on average, some symbols may be received that suffer relatively low levels of ISI. These symbols are 'reliable symbols' and can be used to provide blind estimation of the ISI coefficients. Once the ISI effects of a channel are known, all captured signals may be corrected.

Reliable symbols as a means of improving the performance of information transmission systems

A fast equalization technique is disclosed for systems using high-order constellations where symbols have been corrupted by data correlated noise (ISI). The technique permits ISI estimation to begin immediately upon receipt of captured samples. Training symbols are not required for the operation of the equalization technique. ISI estimation is weighted in accordance to a reliability factor of each captured sample.

Fast, blind equalization techniques using reliable symbols

A first downlink transmission beam and a second downlink transmission beam is determined based on a received user-derived signal. The first downlink transmission beam is substantially uncorrelated with the second downlink transmission beam. The first downlink transmission beam is associated with a portion within a first sector. The second downlink transmission beam is associated with a portion within a second sector. A first signal is diversity encoded to produce a first diversity-encoded signal. A second signal is diversity encoded to produce a second diversity-encoded signal. The first diversity-encoded signal is sent over the first downlink transmission beam. The second diversity-encoded signal is sent over the second downlink transmission beam.

Method and apparatus for received uplinked-signal based adaptive downlink diversity within a communication system

A system and method detect symbols of a modulated signal received via a plurality of channels of a wireless communications system. A symbol transmitted via the channels is initially estimated based on the channel estimate from either pilot symbol or previously estimated symbol, and then channel estimate is updated. The next estimate of the symbol is computed by using updated channel information and maximizing the expectation of the log likelihood function. The next estimate is then quantized according to the signal constellation. The quantized estimate of the symbol is compared with the previous estimate of the symbol to determine if the previous estimate of the symbol and the quantized next estimate of the symbol have converged. Otherwise, the quantized next estimate of the symbol is made as the input for the next iteration, and the updating, optimizing, quantizing, and comparing are repeated until the estimate converges.

Expectation-maximization-based channel estimation and signal detection for wireless communications systems

Method and apparatus for high resolution tracking via mono-pulse beam-forming in a communication system in which the capacity and range of mobile or fixed wireless communication base stations are improved by implementing a single or multiple antenna beam per signal path. Adaptive beam-forming based on up-link direction-of arrival estimation can be performed without using the above-mentioned computationally intensive techniques.

Method and apparatus for high resolution tracking via mono-pulse beam-forming in a communication system

The present invention relates to a method and apparatus for adaptively compensating for channel or system variations in which adaptive compensation is used in the receiver of a digital communication system. The transmitter of the digital communication system includes precoding. The adaptive receiver compensation mitigates the interferences not removed by the transmitter precoder. In an embodiment of the invention, the adaptive compensation can be performed using an adaptive feedforward filter (FFF) and a feedback filter (FBF) in the receiver. The FBF output is generated based on previous values of estimates of the transmitted precoded sequence. The determined value of the FBF coefficients can be periodically relayed to the transmitter to update the precoder coefficients of the transmitter. Alternatively, the value of the FBF coefficients can be relayed to the transmitter after the value of the coefficients exceeds a predetermined threshold. Accordingly, the receiver adaptively and automatically compensates for misadjustments of the fixed transmitter precoder with respect to the actual channel at a given point in time.

Method and apparatus for adaptively compensating channel or system variations in precoded communications system

A detection system identifies a person by rapidly analyzing an image frame from a video camera for the presence of a face by reducing the image in resolution and normalizing the image to compensate for lighting changes and compares the normalized image with a background image to produce a binary interest mask. The most likely position of a face is then determined by identifying a top, bottom and sides of a possible head region to define a bounding box, normalizing the pixel data within the bounding box to further compensate for lighting variations, and resizing the box to match identification templates stored in memory. The best match from the identification templates is provided with a score indicative of the degree of the match. If the score does not exceed a first score threshold, then no face is assumed present. If the score exceeds a first and second score threshold, then a face is assumed present. If the first score threshold is exceeded but the second is not, a further eye location procedure is performed on the data to determine if a face is present.

Apparatus and method for detecting a face in a video image

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Princeton, NJ, United States of America

Stuart C Schwartz