Patent application number | Description | Published |
20080253487 | ADAPTIVE PILOT AND DATA SYMBOL ESTIMATION - Techniques for performing adaptive channel estimation are described. A receiver derives channel estimates for a wireless channel based on received pilot symbols and at least one estimation parameter. The receiver updates the at least one estimation parameter based on the received pilot symbols. The at least one estimation parameter may be for an innovations representation model of the wireless channel and may be updated based on a cost function with costs defined by prediction errors. In one design, the receiver derives predicted pilot symbols based on the received pilot symbols and the at least one estimation parameter, determines prediction errors based on the received pilot symbols and the predicted pilot symbols, and further derives error gradients based on the prediction errors. The receiver then updates the at least one estimation parameter based on the error gradients and the prediction errors, e.g., if a stability test is satisfied. | 10-16-2008 |
20100046595 | SEMI-COHERENT TIMING PROPAGATION FOR GERAN MULTISLOT CONFIGURATIONS - A method for estimating timing in a wireless communication comprises the steps of receiving a plurality of symbol bursts corresponding to a plurality of time slots and selecting a subset of symbols from a first symbol burst of the plurality of symbol bursts. The subset comprises a first midamble symbol. The method further comprises the steps of calculating, for each symbol in the subset, a corresponding midamble estimation error, and determining the lowest calculated midamble estimation error to determine a timing for the first symbol burst. The method further comprises the steps of processing the first symbol burst utilizing the timing determined for the first symbol burst, and processing a second symbol burst of the plurality of symbol bursts utilizing the timing determined for the first symbol burst. | 02-25-2010 |
20100046660 | INTERFERENCE CANCELLATION UNDER NON-STATIONARY CONDITIONS - A method for timing and frequency synchronization in a wireless system is provided. The method comprises the steps of receiving a burst of symbols, selecting a subset of the burst of symbols, iteratively adjusting the subset of the burst of symbols by a plurality of timing offsets and calculating, for each timing offset, a first performance metric corresponding to the adjusted subset. The method further comprises the steps of determining one of the plurality of timing offsets to be a preferred timing offset based upon the first performance metric thereof, iteratively rotating the subset of the burst of symbols by a plurality of frequency offsets and calculating, for each frequency offset, a second performance metric corresponding to the rotated subset, and determining one of the plurality of frequency offsets to be a preferred frequency offset based upon the second performance metric thereof. | 02-25-2010 |
20100046682 | ENHANCED GERAN RECEIVER USING CHANNEL INPUT BEAMFORMING - A method for suppressing interference in a wireless communication is provided. The method comprises receiving a burst of symbols, generating a plurality of timing hypotheses for the burst of symbols, and calculating, for each timing hypothesis, a plurality of weights for an interference suppression filter based upon a subset of the burst of symbols. The method further comprises, for each timing hypothesis, filtering the subset of the burst of symbols using the interference suppression filter with the corresponding plurality of weights, and selecting one of the plurality of timing hypotheses corresponding to a selection criteria. The method further comprises equalizing and decoding the filtered burst of symbols based upon the selected one of the plurality of timing hypotheses. | 02-25-2010 |
20100278035 | METHOD AND SYSTEM FOR MULTI-USER DETECTION USING TWO-STAGE PROCESSING - Systems and methods for multi-user detection in a multiple access system are provided. In one aspect, an apparatus is provided. The apparatus comprises a processing unit configured to process received chips into received symbols for a plurality of users and a computation unit configured to compute a multi-user matrix using a Hadamard matrix, wherein the multi-user matrix relates user symbols for the plurality of users to the received symbols. The apparatus further comprises a detection unit configured to detect the user symbols for the plurality of users using the received symbols and the computed multi-user matrix. | 11-04-2010 |
20100278167 | METHOD AND SYSTEM FOR DATA-AIDED CHANNEL ESTIMATION - Systems and methods for data-aided channel estimation are provided. In one aspect of the disclosure, a channel estimation apparatus is provided. The apparatus comprises a first processing unit configured to process received chips into received symbols and a detection unit configured to detect user symbols from the received symbols. The apparatus further comprises a second processing unit configured to process the detected user symbols into estimated transmit chips and a channel computation unit configured to estimate a channel based on the estimated transmit chips and the received chips. | 11-04-2010 |
20100278216 | METHOD AND SYSTEM FOR INTER-CELL INTERFERENCE CANCELLATION - Systems and methods for inter-cell interference cancellation are provided. In one aspect of the disclosure, an apparatus is provided. The apparatus comprises a cell computation unit configured to compute receive chips for a first interfering cell and a subtraction unit configured to remove the computed receive chips for the first interfering cell from received chips at a receiver. The apparatus further comprises a processing unit configured to process the received chips with the computed receive chips for the first interfering cell removed into received symbols and a detection unit configured to detect user symbols for a target cell from the received symbols. | 11-04-2010 |
20100278217 | METHOD AND SYSTEM FOR MULTI-USER DETECTION USING TWO-STAGE PROCESSING - Systems and methods for multi-user detection are provided. In one aspect of the disclosure, an apparatus is provided. The apparatus comprises a processing unit configured to process a plurality of received chips into a plurality of received symbols for a plurality of users. The apparatus further comprises a computation unit configured to compute a multi-user matrix relating a plurality of user symbols for the plurality of users to the plurality of received symbols and a detection unit configured to detect the plurality of user symbols for the plurality of users using the computed multi-user matrix and the plurality of received symbols. | 11-04-2010 |
20100278218 | METHOD AND SYSTEM FOR MULTI-USER INTERFERENCE CANCELLATION - Systems and methods for multi-user interference cancellation are provided. In one aspect of the disclosure, an apparatus is provided. The apparatus comprises a processing unit configured to process received chips into received symbols for a plurality of users and a detection unit configured to detect user symbols from the received symbols. The apparatus also comprises an interference cancellation unit configured to compute multi-user interference using the detected user symbols and to remove the computed multi-user interference from the received symbols. The apparatus further comprises a redetection unit configured to redetect user symbols from the received symbols with the computed multi-user interference removed. | 11-04-2010 |
20100278284 | METHOD AND SYSTEM FOR SYMBOL DETECTION USING SUB-CONSTELLATIONS - Systems and methods for symbol detection using sub-constellations are provided. In one aspect of the disclosure, an apparatus is provided. The apparatus comprises a processing unit configured to process received chips into received symbols for a plurality of users, a first detection unit configured to detect first components of user symbols for the plurality of users based on the received symbols and a computation unit configured to compute a portion of the received symbols due to the first components of the user symbols. The apparatus further comprises a second detection unit configured to detect second components of the user symbols based on the received symbols with the computed portion removed and a combining unit configured to detect the user symbols by combining the first components of the user symbols with the respective second components of the user symbols. | 11-04-2010 |
20100309956 | METHOD AND SYSTEM FOR INTERFERENCE CANCELLATION - Systems and methods for interference cancellation at a receiver in a wireless communication system are provided. In one aspect, a method for interference cancellation is provided. The method comprises providing total received chips received from a plurality of cells. The method also comprises successively estimating received chips for each of the plurality of cells in a plurality of iterations, wherein each of the plurality of iterations after a first iteration comprises canceling previously estimated received chips for one or more of the plurality of cells from the total received chips, and estimating received chips for one of the plurality of cells using the total received chips with the previously estimated received chips for the one or more of the plurality of cells cancelled out. | 12-09-2010 |
20100310026 | ITERATIVE INTERFERENCE CANCELLATION RECEIVER - A method for suppressing interference in a wireless communication comprises receiving a burst of symbols, filtering the burst of symbols using an interference suppression filter with a first plurality of weights, decoding the filtered burst of symbols to generate data corresponding to the burst of symbols, encoding the data to generate a re-encoded burst of symbols, calculating a second plurality of weights for the interference suppression filter based upon the re-encoded burst of symbols, filtering the re-encoded burst of symbols using the interference suppression filter with the second plurality of weights, and decoding the filtered re-encoded burst of symbols. | 12-09-2010 |
20110051859 | SYMBOL ESTIMATION METHODS AND APPARATUSES - A novel symbol estimation method produces intersymbol interference free symbols by detecting interfering symbols in an interfering channel. A channel estimate is refined for additional improvements. The method can lends itself as a serial or parallel algorithm implementation. The symbol estimation method includes using an initial estimate of received symbols and calculating a refined estimate of the received symbols using a channel estimate. The refined estimate is calculated by performing parameterization of intersymbol interference by symbols other than the symbol being refined and selecting a refined value for the symbol being refined by evaluating an optimization function. Symbol estimates are refined in multiple iterations, until a predetermined iteration termination criterion is met. Parameterization of ISI contribution of other symbols results in reduced computation by reducing total number of unknown variables in the refinement operation. | 03-03-2011 |
20110051864 | MULTI-STAGE INTERFERENCE SUPPRESSION - A multi-stage interference suppression receiver includes a short equalizer section configured to operate on a first portion of a received signal received over a channel to produce a first equalized signal and a first estimate of the channel, a channel estimator section configured to operate on the first equalized signal to produce a second equalized signal, the channel estimator section comprising a linear estimator and a non-linear estimator, a long equalizer section configured to operate on a second portion of the received signal to produce a first estimate of symbols in the received signal and a second estimate of the channel and an interference canceller section configured to operate on the first estimate of symbols in the received signal to generate a second estimate of symbols in the received signal based on, at least in part, the second estimate of the channel. | 03-03-2011 |
20110286498 | APPARATUS AND METHOD FOR CHANNEL ESTIMATION USING COMPRESSIVE SENSING - An apparatus and method for channel estimation comprising obtaining a response matrix G(l) using Q quantity pilots; constructing a sensing matrix W | 11-24-2011 |
20110286507 | APPARATUS AND METHOD FOR CHANNEL ESTIMATION USING COMPRESSIVE SENSING BASED ON TAYLOR SERIES EXPANSION - An apparatus and method for channel estimation comprising determining a channel impulse response using a Taylor series expansion with a plurality of Taylor series coefficients; determining a channel frequency response based on the channel impulse response; collecting the channel frequency response over a plurality of symbols to obtain a composite channel frequency response; generating a sensing matrix based on the Taylor series expansion; and determining the plurality of Taylor series coefficients based on the composite channel frequency response and the sensing matrix using compressive sensing channel estimation. | 11-24-2011 |
20110286558 | APPARATUS AND METHOD FOR COMPRESSIVE SENSING TAP INDENTIFICATION FOR CHANNEL ESTIMATION - An apparatus and method for compressive sensing tap identification for channel estimation comprising identifying a set of significant taps in the time domain; representing a time-flat channel response using a Taylor series expansion with the set of significant taps; converting the time-flat channel response to a vectorized channel response; transforming the vectorized channel response to a compressive sensing (CS) polynomial frequency response; aggregating the CS polynomial frequency response into a stacked frequency response; converting the stacked frequency response into a measured pilot frequency response; estimating a channel parameter vector based on the measured pilot frequency response; and generating a reconstructed channel response from the channel parameter vector. | 11-24-2011 |
20110305303 | INTERFERENCE CANCELLATION UNDER NON-STATIONARY CONDITIONS - A method for timing and frequency synchronization in a wireless system is provided. The method comprises the steps of receiving a burst of symbols, selecting a subset of the burst of symbols, iteratively adjusting the subset of the burst of symbols by a plurality of timing offsets and calculating, for each timing offset, a first performance metric corresponding to the adjusted subset. The method further comprises the steps of determining one of the plurality of timing offsets to be a preferred timing offset based upon the first performance metric thereof, iteratively rotating the subset of the burst of symbols by a plurality of frequency offsets and calculating, for each frequency offset, a second performance metric corresponding to the rotated subset, and determining one of the plurality of frequency offsets to be a preferred frequency offset based upon the second performance metric thereof. | 12-15-2011 |
20110312275 | SIGNAL RECEPTION METHOD AND APPARATUS FOR NON-STATIONARY CHANNELS - A signal reception method includes receiving a signal over a channel, producing a first equalized signal, a first interference suppression filter and a first estimate of the channel using a portion of a the received signal, dividing the received signal into a plurality of signal blocks, and for each one of the plurality of signal blocks, producing a second equalized signal using a portion of the first equalized signal by selecting from one of a linear estimator or a non-linear estimator and estimating symbols received in the one of the plurality of signal blocks based on the second equalized signal. | 12-22-2011 |
20110319045 | LINEAR INTERFERENCE CANCELLATION RECEIVER - Interference cancellation at a user equipment includes performing channel estimation for each component of an aggregate received signal using at least one received midamble of at least one time slot. The aggregate received signal is received from at least one Node B. A combined channel is computed for each channelization code based on the channel estimation. A linear transfer function is obtained for all user equipment within a cell. This linear transfer function includes a combined channel for each channelization code. An equalization matrix is derived from the linear transfer function and then applied to the aggregate received signal to obtain the component intended for the user equipment. | 12-29-2011 |
20120069753 | CHANNEL ESTIMATION BASED ON MIDAMBLE - Channel estimation at a user equipment includes estimating channel quality of at least one channel. A first algorithm or a second algorithm is selected based on the estimated channel quality. Channel estimation is performed based on the selected algorithm. The first algorithm may be a midamble multiplication-based algorithm. The second algorithm may be a midamble division algorithm. Channel estimation may also include estimating noise of a channel and adaptively setting a threshold based on the estimated noise to refine the channel estimation. The estimating channel quality, selecting of a first or second algorithm and channel estimation may be performed iteratively for contributing signals on a channel. An adaptive threshold may be modified across iterations. The channel estimation may also include determining a delay profile of a channel to refine the channel estimation. | 03-22-2012 |
20120093269 | APPARATUS AND METHOD FOR TWO-STAGE LINEAR/NONLINEAR INTERFERENCE CANCELLATION - An apparatus and method for a two-stage linear/nonlinear interference cancellation comprising processing a receive signal to produce a first descrambled signal; and processing the first descrambled signal to produce a detected signal. In one aspect, a first interference canceller module is used for processing the received signal and a second interference canceller module is used for processing the first descrambled signal. In one aspect, the first interference canceller is a linear interference canceller (IC) and the second interference canceller is a linear/nonlinear interference canceller (IC). | 04-19-2012 |
20120224498 | BAYESIAN PLATFORM FOR CHANNEL ESTIMATION - Certain aspects of the present disclosure propose a method for estimating a channel utilizing Sparse Bayesian Learning (SBL) algorithm. The proposed method employs a Basis expansion (e.g., polynomial) channel model, and iteratively performs SBL algorithm to adjust parameters of the channel model. | 09-06-2012 |
20120281747 | EQUALIZER TAP DETERMINATION - A method includes performing an operation based on transformed channel data and transformed signal data to generate a transform representation of multiple taps. The transformed channel data and the transformed signal data correspond to data received at a receiver. An inverse transform of the transform representation is determined to generate multiple taps for use at an equalizer of the receiver. At least one of the multiple taps is discarded to generate updated filter taps for the equalizer. | 11-08-2012 |
20130128942 | ADVANCED INTERFERENCE CANCELLATION FOR PRECODED GSM EDGE RADIO ACCESS NETWORK (GERAN) - An interference cancellation receiver for a pre-coded orthogonal frequency division multiplexed (OFDM) based system combines temporal interference cancellation within the OFDM framework. Multi-path equalization and inter-symbol interference (ISI) cancellation are performed on a time domain channel estimate of a received signal. An output from the multi-path equalization is transformed to the frequency domain. Inter-channel interference (ICI) is performed in the frequency domain on an equalized signal from the multi-path equalization after transforming the equalized signal from the time domain to the frequency domain. | 05-23-2013 |
20130148711 | SOFT LINEAR AND NON-LINEAR INTERFERENCE CANCELLATION - A two stage interference cancellation (IC) process includes a linear IC stage that suppresses co-channel interference (CCI) and adjacent channel interference (ACI). The linear IC stage disambiguates otherwise super-trellis data for non-linear cancellation. Soft linear IC processing is driven by a-posteriori probability (Apop) information. A second stage performs expectation maximization/Baum Welch (EM-BW) processing that reduces residual ISI left over from the first stage and also generates the Apop which drives the soft linear IC in an iterative manner. | 06-13-2013 |
20140093021 | METHODS AND APPARATUSES FOR ENHANCED RECEIVED SIGNAL PROCESSING BASED ON A DATA-SIGNAL-AIDED CHANNEL IMPULSE RESPONSE ESTIMATION - The present disclosure presents methods and apparatuses for enhanced received signal processing using signal-based channel impulse response (CIR) estimation. For example, according to an example method presented herein, a user equipment (UE) or a component therein may receive a signal corresponding to a transmitted signal sent by a network entity, wherein the transmitted signal comprises at least a data channel, estimate chip contents of the transmitted signal, based on the received signal including the data channel, to obtain estimated chip contents, and compute an estimated channel impulse response (CIR) based on at least the estimated chip contents. Based on this estimated CIR, the UE may thereafter reprogram a received signal reconstruction filter, perform interference cancelation procedures, and/or adjust one or more equalizer taps. By performing such functions, the UE may exhibit improved communication characteristics and enable a more robust user experience. | 04-03-2014 |