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Interference or noise reduction

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375 - Pulse or digital communications

375316000 - RECEIVERS

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Class / Patent application numberDescriptionNumber of patent applications / Date published
375350000 By filtering (e.g., digital) 161
375347000 Diversity (frequency or time) 59
375349000 Plural signal paths in receiver 28
375348000 Intersymbol interference 26
375351000 Gating, blanking, etc. 2
20090268857Cycle slip detection for timing recovery - A method and an arrangement for cycle slip detection for timing recovery of a received analog signal comprising asynchronously sampled digital data are recommended. More specifically a fully digital implementation of a timing recovery control loop using a technique known as interpolated timing recovery and improved cycle slip detection as well as improved cycle slip correction based on said cycle slip detection are recommended. The method comprises the steps of using an output signal of the loop filter in the control loop for timing recovery, generating averaged timing error values from said filtered timing error signal and accumulating changes of the averaged timing error values in adjacent blocks of samples which exceed a first threshold. Accumulated averaged timing error changes of adjacent blocks which exceed a second threshold are then declared as cycle slip and the number of cycle slips is determined by a third threshold being a tolerance threshold. Furthermore, a first-in, first-out memory is provided for sample insertion or deletion, which means that a sample insertion or sample deletion takes place in the sample domain with increased reliability and an improved method for cycle slip detection is recommended due to increased robustness against noise and inappropriately chosen timing loop parameters, which is also applicability for systems with frequency-offsets. The method and a corresponding arrangement are applicable for timing recovery of signals having high intersymbol interference, low signal to noise ratio and frequency offset as e.g. provided by reading a high-density data storage medium or received by mobile phone.10-29-2009
20090262873Noise removal device and noise removal method - The invention provides a noise removal device and method capable of more proper interpolation on an input signal. The noise removal device is for removing noise in an input signal and includes: a noise detector detecting noise in an IF signal and outputting a noise detection signal; an interpolation controller determining a period and amount of interpolation for noise correction processing, based on the IF signal and the noise detection signal; and a noise gate processor performing the noise correction processing on the IF signal, based on the interpolation period and amount supplied from the interpolation controller. The interpolation controller sets a predetermined first interpolation period, based on a first noise detection signal inputted from the noise detector, and redefines a second interpolation period longer than the first interpolation period when a second noise detection signal is detected within the first interpolation period.10-22-2009
Entries
DocumentTitleDate
20110176645METHOD AND APPARATUS FOR ESTIMATING NOISE AND INTERFERENCE POWER IN WIRELESS TELECOMMUNICATIONS SYSTEM - A method and apparatus for estimating a noise and interference power in a wireless communication system are provided. Once a receiver receives an uplink signal from a terminal through an uplink channel to which semi-orthogonal sequences can be mapped, an estimator estimates an average power of signal components of the uplink signal and an average power of noise and interference components of the uplink signal by using correlation characteristics of the semi-orthogonal sequences, and a converter converts the average power of the signal components and the average power of the noise and interference components into a Carrier-to-Noise and Interference Ratio (CNIR). In this way, by simply and accurately estimating a CINR using semi-orthogonality of an uplink channel, stable and flexible system management becomes possible.07-21-2011
20110206168CHANNEL ESTIMATOR - According to an embodiment, a channel estimator includes a channel response estimation section configured to estimate a channel response by correlation processing between a received signal and a known pattern signal; a path power calculation section configured to measure power of each path within an output of the channel response estimation section; a noise power calculation section configured to measure noise power from the output of the channel response estimation section; a path determination section configured to determine paths to be preserved by using the path power outputted from the path power calculation section and the noise power outputted from the noise power calculation section; and a noise removal section configured to remove values in time domain excepting the paths determined at the path determination section, from the output of the channel response estimation section.08-25-2011
20090196384Direct Radio Frequency (RF) Sampling With Recursive Filtering Method - A radio receiver 08-06-2009
20110188618RF/DIGITAL SIGNAL-SEPARATING GNSS RECEIVER AND MANUFACTURING METHOD - An RF/digital signal-separating receiver is provided for GNSS and other RF signals. The receiver includes a first master antenna and a second slave antenna, which are positioned in spaced relation for directional, radio compass applications. First and second downconverters and first and second ADCs are located under the first and second antennas in analog signal areas, which configuration minimizes cross-coupling RF signals from the antennas and reduces noise. The first and second ADSs are connected to respective first and second correlators in a digital signal location, which is centrally located relative to the antennas. The correlators are connected to a microprocessor for computing distances for the received signals, from which the receiver's orientation or attitude is determined. A method of manufacturing receivers with this configuration is also disclosed.08-04-2011
20110194656Correction of Alternating I/Q Imbalance and Frequency Offset Impairments - A method for communication includes receiving a signal, which carries data bits and is distorted by multiple impairments including one or more frequency offsets and one or more In-phase/Quadrature (I/Q) imbalances. A corrected signal is produced by applying to the received signal a sequence of corrections to compensate for the impairments. The sequence includes a first and a third correction of one correction type and a second correction of another correction type intervening between the first and third corrections in the sequence, the correction types consisting of frequency offset corrections and I/Q imbalance corrections. The data bits are extracted from the corrected signal.08-11-2011
20100158172DIGITAL DIRECT CONVERSION RECEIVER BASED ON VARIABLE DELAY AND CONSTANT INTERPOLANT FOR RECEIVING RADIO FREQUENCY SIGNAL AND METHOD THEREOF - Disclosed is a digital direct conversion receiver including a clock generation and a distribution unit to generate a clock signal having a time difference that generates a predetermined phase difference, a Track & Holder (T&H) to perform sampling of a radio frequency (RF) signal selected by a tunable RF filter with a selected sampling frequency and down converting of the sampled signal, and to generate the predetermined phase difference between sampled signals by using the clock signal having the time difference during the down-conversion, an analog-digital (AD) converter to generate a sample stream having phase difference information from the down-converted sampled signal, and a complex interpolant to eliminate an image component from the sample stream using a phase difference between a plurality of sample streams.06-24-2010
20100074381METHODS AND SYSTEMS FOR IMPROVING ITERATIVE SIGNAL PROCESSING - A method for iteratively decoding a set of encoded samples received from a transmission channel is provided. A data signal indicative of a noise level of the transmission channel is received. A scaling factor is then determined in dependence upon the data signal and the encoded samples are scaled using the scaling factor. The scaled encoded samples are then iteratively decoded. Furthermore, a method for initializing edge memories is provided. During an initialization phase initialization symbols are received from a node of a logic circuitry and stored in a respective edge memory. The initialization phase is terminated when the received symbols occupy a predetermined portion of the edge memory. An iterative process is executed using the logic circuitry storing output symbols received from the node in the edge memory and a symbol is retrieved from the edge memory and provided as output symbol of the node. Yet further an architecture for a high degree variable node is provided. A plurality of sub nodes forms a variable node for performing an equality function in an iterative decoding process. Internal memory is interposed between the sub nodes such that the internal memory is connected to an output port of a respective sub node and to an input port of a following sub node, the internal memory for providing a chosen symbol if a respective sub node is in a hold state, and wherein at least two sub nodes share a same internal memory.03-25-2010
20100074380COUPLING CHANNEL NOISE CANCELING CIRCUIT - A coupling channel noise canceling circuit includes a signal detecting unit, a gain setting unit, a cancel signal generating unit, and a noise canceling unit. The signal detecting unit detects a phase difference and a voltage difference between a broadcast RX signal and a noise cancel signal in a set mode. The gain setting unit outputs compensation gain values corresponding to the phase difference and the voltage difference from the signal detecting unit in the set mode. The cancel signal generating unit sets the compensation gain values from the gain setting unit as an amplification gain for amplification of a communication TX signal in the set mode, and amplifies the communication TX signal by a predetermined gain to generate the noise cancel signal in the set mode and an operation mode. The noise canceling unit cancels an interference noise from the broadcast RX signal by using the noise cancel signal from the cancel signal generating unit in the operation mode.03-25-2010
20100046680Communication Device and Control Method - A communication device according to the present invention includes a receiver configured to receive, through a radio link, packet signals each including a known signal indicating information known by the communication device and an unknown signal indicating information not known by the communication device, and a combiner configured to combine the packet signals while decreasing noise signals included in each of the packet signals. The communication device includes a correlation comparator configured to compare a correlation between the known signals in each of the packet signals with a correlation between the unknown signals in each of the packet signals, and a combining scheme controller configured to control a scheme of combining the packet signals, on the basis of the comparison result by the correlation comparator.02-25-2010
20130034195INTERFERENCE SUPPRESSION METHOD AND INTERFERENCE SUPPRESSION DEVICE - A reception station 02-07-2013
20090185649Decision Directed Flicker Noise Cancellation - A decision directed flicker noise canceller for reducing flicker noise in a modulated input signal according to an embodiment of the present invention includes a decision circuit, a conversion circuit, first and second adders and a filter. The decision circuit provides signal decisions based on the input signal. The conversion circuit provides selected signal values based on the signal decisions. The first adder subtracts the selected signal values from signals based on the input signal to provide a flicker noise estimate. The filter receives and filters the flicker noise estimate and the second adder subtracts the filtered flicker noise estimate from the input signal and provides a corrected input signal. In a feedback configuration, the second adder is located in a feedback position before the decision circuit in the signal processing path. In a feed-forward configuration, the second adder is located in a feed-forward position after the decision circuit.07-23-2009
20100104053APPARATUS AND METHOD FOR ESTIMATING INTER-CARRIER INTERFERENCE POWER AND NOISE POWER IN A CHANNEL - An estimation method is provided for use in a receiver of an OFDM (orthogonal frequency division multiplexing) system to estimate the ICI (inter-carrier interference) and the noise power of a channel. Two pilot signals respectively carried by two subcarriers are received from the channel wherein the two pilot signals are adjacent and differ by a first phase angle. Another two pilot signals respectively carried by another two subcarrier are received from the channel wherein the another two pilot signals are adjacent and differ by a second phase angle. According to some embodiments of the invention, these phases are correlated with the ICI power, but are uncorrelated with the noise power. The estimation method then individually estimates the ICI power and noise power according to the first phase and the second phase.04-29-2010
20090154620SYSTEMS AND METHODS FOR INTERFERENCE CANCELLATION IN A RADIO RECEIVER SYSTEM - A system and method for interference cancellation is provided to cancel/greatly reduce the interference of a wireless network. The interferers are separated from a desired signal using independent component analysis by hypothesizing the transmitting sequence. An optional whitening filter is used after the signal separation to improve the signal conditioning. The separated signal is processes by a second pass channel estimation to improve the signal channel estimation and is fed to MLSE algorithm, such as a Viterbi algorithm, for signal detection. The system and method provides significant gain over all previous methods with no limitation to the frequency type or specific interference profile such as the ratio of the dominant interferer to the other interferers. It is possible to separate the interferers without prior knowledge of the specific parameters of the interferers and with much less complexity than conventional joint demodulation detection methods. The algorithm employed is considered a blind estimation approach which makes it attractive for wireless devices that have limited power resources.06-18-2009
20090154619FREQUENCY ERROR ESTIMATOR USING SECOND-ORDER LOOP FILTER AND OPERATING METHOD OF THE FREQUENCY ERROR ESTIMATOR - A frequency error estimator and an operating method of the frequency error estimator are provided. In the frequency error estimator and the operating method of the frequency error estimator, a frequency error between a transmitter and a receiver of a mobile communication system using a reference code is calculated, thereby improving the precision of estimation while reflecting variations in frequency over time.06-18-2009
20090154618Device and method for calculating Channel State Information - Device and method for calculating channel state information (CSI) are disclosed. The device and method are applied to calculate the channel state information of a dual-carrier modulation system. When a channel equalization value is transmitted into this system, an absolute-value computing unit computes the absolute value for each equalization value. The absolute-value computing unit is electrically connected to a channel classifying unit that is used to separate signals to two channels. Every channel is connected to the equalization-value comparing unit. One smaller value resulted from a comparison operation is employed as the new-defined CSI for these two channels. Afterward, this CSI can be used in a decoder for enhancing the performance of dual-carrier modulation system in a multi-path fading channel.06-18-2009
20100040179CHANNEL ESTIMATION - Aspects describe channel estimation in an OFDM system. Baseline DFT-based channel estimation can be performed and scaling can be applied to mitigate distortion in the DFT-based estimations. In some aspects, baseline DFT-based channel estimation can be performed and tones for which DFT-based estimate is deemed unreliable can have MMSE based processing applied locally. If orthogonal sequence is deemed excessive, orthogonal sequence cancellation can be applied prior to the MMSE based processing.02-18-2010
20120183106CIRCUIT, CONTROLLER AND METHODS FOR DYNAMIC ESTIMATION AND CANCELLATION OF PHASE AND GAIN IMBALANCES IN QUARDRATURE SIGNAL PATHS OF A RECEIVER - A controller and a circuit work together to enable a selective and dynamic adjustment to correct phase and gain imbalances in quadrature signal paths of a receiver. Under select conditions, it has been determined that statistical estimates of gain and phase imbalance can be applied to adjust signals in the quadrature signal paths of a receiver. The controller validates the select conditions before updating the estimate of the gain imbalance and the estimate of the phase imbalance. The controller directs a compensator under select operating conditions such that validated dynamic estimates of the gain and phase imbalance or calibration data is applied to the quadrature signal paths. The controller disables the compensator and enables an estimator and a calculator when estimates are unavailable for the present operating conditions.07-19-2012
20100067628Adaptive Pattern Dependent Noise Prediction on a Feed Forward Noise Estimate - Various embodiments of the present invention provide systems and methods for processing data. As one example, a circuit is disclosed that includes a pre-detector that detects an estimated pattern in a digital input signal, and a summation element that subtracts the estimated pattern from the digital input signal to yield a noise estimate. The circuit further includes a data dependent noise prediction filter that is adaptively tuned to detect a noise pattern, and that filters the noise estimate to provide a filtered noise estimate.03-18-2010
20100067627Maximum A Posteriori Interference Estimation in a Wireless Communication System - Methods and apparatus are disclosed for estimating inter-cell interference levels for resource elements of a received Orthogonal Frequency-Division Multiplexing (OFDM) signal. In an exemplary method in a wireless receiver, a reference symbol interference levels is measured for each of a plurality of reference symbols in a received OFDM signal, and interference scaling factors are mapped to each of a plurality of resource elements of the received OFDM signal. Each interference scaling factor reflects the probability that the corresponding resource element or group of resource elements is subject to interference from an interfering OFDM signal. Interference levels for each of the resource elements are then estimated as a function of the measured reference symbol interference levels and the interference scaling factors.03-18-2010
20100135444MULTI-CARRIER RECEIVER WITH DYNAMIC POWER ADJUSTMENT AND METHOD FOR DYNAMICALLY ADJUSTING THE POWER CONSUMPTION OF A MULTI-CARRIER RECEIVER - A method for dynamically adjusting the power consumption of a multi-carrier receiver and a multi-carrier receiver with dynamically power adjustment. The method includes receiving a multi-carrier signal, wherein the multi-carrier signal comprises a plurality of sub-carriers. Channel characteristics of each sub-carrier are estimated according to the demodulated multi-carrier signal. ICI strength is estimated from the demodulated multi-carrier signal. A system performance is detected. The estimated ICI is subtracted when the ICI strength exceeds an ICI threshold and the system performance is less than a system performance threshold. The demodulated multi-carrier signal is then equalized is based on the estimated channel characteristics, and the system performance is updated according to the equalized multi-carrier signal.06-03-2010
20090304131LOW COST NOISE FLOOR REDUCTION - A method and system to reduce the noise floor of a communications system is disclosed. The system may be incorporated into any device that provides binary samples from a datastream, such as a cordless telephone system. The system is configured to determine a number of bits of the binary samples that are affected by noise. The system is then able to remove the noise by setting those bits to a fixed value. The fixed value may depend on whether the sample is positive or negative. The value to set may be chosen so that the least significant bits of each sample come as close as possible to 0 for that particular numerical representation system. The system can be integrated with other known signal processing methods.12-10-2009
20110013734INGRESS NOISE REDUCTION IN A DIGITAL RECEIVER - The invention provides a device (D01-20-2011
20090016473RECEIVED SIGNAL QUALITY DETERMINATION - A method of generating a received signal quality signal in a communication system, the method comprising: receiving a signal from a physical channel, extracting a transport channel format combination indicator from the received signal, processing one or more transport channel signals, contained in the received signal, in accordance with the extracted transport channel format combination indicator, said processing including at least channel decoding, and generating a received signal quality signal in dependence on the quality of the or each transport channel signal prior to channel decoding.01-15-2009
20120224662RECEIVER APPARATUS, RECEIVING METHOD, AND PROGRAM - An interpolation method selection processing section 09-06-2012
20120224661Digital Equalization Process and Mechanism - A filter is created by sampling noise during an inter-frame gap of a received signal, sampling a data frame preamble from within a data frame of the received signal, and computing filter coefficients based on the noise sampled during the inter-frame gap and the data frame preamble sampled from within the data frame.09-06-2012
20090074119MULTI-PULSE FREQUENCY SHIFTED (MPFS) MULTIPLE ACCESS MODULATION FOR ULTRA WIDEBAND - The multi-pulse frequency shifted technique uses mutually orthogonal short duration pulses o transmit and receive information in a UWB multiuser communication system. The multiuser system uses the same pulse shape with different frequencies for the reference and data for each user. Different users have a different pulse shape (mutually orthogonal to each other) and different transmit and reference frequencies. At the receiver, the reference pulse is frequency shifted to match the data pulse and a correlation scheme followed by a hard decision block detects the data.03-19-2009
20100091919Joint use of multi-carrier and single-carrier multiplexing schemes for wireless communication - A communication system that facilitates transmissions in accordance with a single-carrier (SC) multiplexing scheme, a multi carrier (MC) multiplexing scheme or a combination thereof is disclosed. Based on various factors such as attributes associated with a UE (user equipment) or availability of resources, a base station can signal to the UE an appropriate multiplexing scheme to be adopted for particular transmissions. The UE can be scheduled for transmission in a semi-static mode wherein the UE employs the transmission scheme for a particular time interval or it may change the mode dynamically for different transmissions. For transmissions from the UE comprising a plurality of data streams with dissimilar attributes, the base station implements a MIMO (multiple input multiple output) system for the UE. This facilitates a UE to dynamically switch between or simultaneously adopt the various multiplexing schemes for communications and thereby fully utilize advantages associated with the different schemes.04-15-2010
20100091918DIGITAL RECEIVER, CONTROLLING METHOD OF THE APPARATUS, COMPUTER PROGRAM PRODUCT, AND RECORDING MEDIUM RECORDING THEREON THE PRODUCT - Provided are: plural circuit components including a circuit component which constitutes a receiving unit receiving a signal sequence which is arranged so that a desired signal and a signal different from the desired signal are lined up in time series, the desired signal indicating desired data which includes at least one of text data, sound data, image data, and a computer program product; and an operating parameter changing unit which changes an operating parameter of at least one of the plural circuit components, during a period in which the receiving unit receives the signal different from the desired signal.04-15-2010
20130064334INTEGRATED CIRCUIT HAVING FREQUENCY DEPENDENT NOISE AVOIDANCE - A clock source generates a first clock signal for clocking a first clocked module and a rate adapting module produces an operation dependent clock signal from the first clock signal for clocking a second clocked module that is rate dependent. The first clock signal has a rate such that frequency dependent noise components associated with the first clock signal are outside a given frequency range that causes adverse performance in the first clocked module.03-14-2013
20130163704Interference Cancellation Method with Multiple Data Layer MIMO Transmission - A method and apparatus are provided for cancelling interferences of a received MIMO RF signal. The method includes: receiving a signal y; an initial step of obtaining, from the received signal y, at least one data representative of the received signal, called decoded data; computing the decoded data as a function of at least one predetermined criterion, delivering feedback data and a feedback decision; and, as a function of the feedback decision, at least one iteration of the following steps: constructing a set of feedback symbols from the feedback data; obtaining, from the set of feedback symbols, at least one data representative of a feedback decoded signal, called feedback decoded data; computing the at least one feedback decoded data as a function of the at least one predetermined criterion, delivering the feedback data.06-27-2013
20090060105INTERFERENCE LEVEL ESTIMATION OF PATH MONITORING IN W-CDMA USING THE ORDER STATISTICS OF BEAULIEU SERIES - A technique for interference level estimation for a WCDMA system based on the low order statistics of Beaulieu Series is provided. Correlation of a locally generated copy of a dedicated physical control channel (DPCCH) with the input samples of the radio frequency message is performed using low order statistics of a Beaulieu Series to estimate an interference level and thereby implicitly separate a set of multipath components from a noise floor.03-05-2009
20090238316Receivers and methods for controlling operation of receivers - A method for controlling operation of a receiver may include: generating an operation control signal based on a signal-to-noise ratio (SNR) value of an N09-24-2009
20090238315SIGNAL PROCESSING DEVICE AND SIGNAL PROCESSING METHOD - The present invention discloses a signal processing device and a signal processing method. The signal processing device includes a plurality of receiving devices, a storage module, a weighting module, and a processing module. Each of the receiving devices is capable of receiving an original signal stream, thus the plurality of receiving devices can generate a set of signal streams. The storage module is used for storing a plurality set of signal streams generated by the plurality of receiving devices. The weighting module can generate plurality sets of rotated signal streams according to a reference phase and the plurality sets of signal streams, and further generate a set of weighting signal according to the rotated signal streams. And, the processing module can generate a set of weighting signal streams according to the set of weighting signal and the plurality set of signal streams.09-24-2009
20090232260LEAKAGE SIGNAL CANCELLATION APPARATUS - A quadrature modulator divides a part of a transmitted signal to generate a cancel signal. A signal comparator compares the amplitude and phase of the cancel signal which is generated by the quadrature modulator with those of a received signal, and outputs signals corresponding to the comparison results to the quadrature modulator. The quadrature modulator generates the cancel signal on the basis of the output signals of the signal comparator, and these components perform feedback control such that the cancel signal has the same amplitude as the leakage signal and is in phase with the leakage signal. A combiner combines the cancel signal with an antiphase cancel signal, which is made to be in opposite phase with the cancel signal outputted from the quadrature modulator, to cancel out the leakage signal.09-17-2009
20090046819METHOD OF REDUCING QUANTIZATION NOISE - There is described a system (02-19-2009
20090010368VARIABLE RATE CODING FOR FORWARD LINK - A technique for encoding a signal used in a digital communication system in which individual traffic channel data rates may be adapted to specific channel conditions. In particular, a forward error correction coding rate is adapted for individual channels while at the same time maintaining a fixed block size independent of the FEC coding rate. This allows the system data rate to adapt to the channel conditions experienced by a specific user. Thus, users experiencing good communication conditions with low multipath distortion may be allocated higher capacity, whereas users with significant multipath distortion may make use of lower rate (higher levels of coding) error codes to maintain high quality. Messages are sent from a transmitter to a receiver to inform the receiver of the coding rate implemented at any given point in time. These parameters may be adjusted independent of transmitted power level through the expedient of ensuring that size of a transmitted frame remains constant, while permitting the ability to change FEC coding rates and FEC block sizes.01-08-2009
20090010367MULTI-BAND SINGLE-CARRIER MODULATION - Multi-band single-carrier modulation. A novel approach is presented by which interference compensation may be performed for signals received by a piconet operable device. The piconet operable device may be implemented within a region that includes two or more SOPs (Simultaneously Operating Piconets). Estimation of the level and location of interference is performed and the input to a decoder (within the piconet operable device) is selectively weighted to ensure that the effect of any existent interference within the signal received by the piconet operable device is minimized. Different interference levels are dealt with differently. For one example, portions of the received signal having undergone a large amount of interference may be simply treated as erasures with respect to the input the decoder. For another example, portions of the received signal having undergone some smaller degree of interference, but some interference nonetheless, may be de-weighted before being provided to the decoder.01-08-2009
20090010366METHOD AND DEVICE FOR SUPPRESSING NARROWBAND INTERFERENCE - The method obtains an interference detection result by detecting sampled digital signals in real time in a transform domain, then maps the interference detection result into an interference suppression pulse function on the basis of a unit noise pulse function, and carries out interference suppression filtering in the transform domain according to the interference suppression pulse function. The present invention is capable of detecting narrowband interference such as monotone, frequency modulation, and phase modulation interferences in a receive channel adaptively in real-time, and suppressing the interference adaptively according to the quantity, energy and bandwidth of the interference, so as to reduce the influence of the interference. Therefore, the present invention may enhance robustness of the communication system against interference. Moreover, the present invention does not need multiple notch devices, costs low and may be implemented simply and reliably.01-08-2009
20130163705ANTENNA - A phased array antenna for providing a radiation pattern having at least one communication beam, includes a plurality of antenna elements, each with an antenna element signal having a phase relationship and an amplitude relationship to the other element signals; a digital signal processing arrangement providing a digital beamforming network; and an analogue beamforming network arranged to reduce exposure of the digital signal processing arrangement to an interfering signal. Analogue beamforming weights are selected to generate a null in the radiation pattern in a direction corresponding to the interfering signal.06-27-2013
20090003496RECEPTION APPARATUS - A reception apparatus is provided with a semiconductor integrated circuit device and a UHF-fixed band-pass filter provided in a stage preceding the semiconductor integrated circuit device. The semiconductor integrated circuit device includes a frequency converter, a to-be-frequency-converted-signal transmission line through which a to-be-frequency-converted signal is fed to the frequency converter, a local-oscillation-signal transmission line through which a local oscillation signal is fed to the frequency converter and an unnecessary-signal attenuation circuit, provided in the to-be-frequency-converted-signal transmission line, that attenuates an unnecessary signal included in signals transmitted through the to-be-frequency-converted-signal transmission line.01-01-2009
20080317177Wiener filtering arrangement - A Wiener filtering arrangement includes a first filter configured to output at an output first signal estimates and a polyphase filter having an input configured to receive the first signal estimates and an output. The polyphase filter is configured to use only a subset of a plurality of reference signals to provide second signal estimates at said output.12-25-2008
20120236974RECEIVER - According to one embodiment, a receiver includes an EVM calculating unit which calculates an EVM (Error Vector Magnitude) value of an input signal. Further, a receiver includes a control unit which determines whether the frequency of EVM calculation is reduced or not, according to a comparison between the EVM value and a predetermined range including a threshold for switching processing by the EVM value. Further, a receiver includes a data reducing unit which controls the calculation interval of the EVM value in the EVM calculating unit, according to the determination result by the control unit.09-20-2012
20120269305BANG-BANG OFFSET CANCELLATION (AUTOZERO) - A receive channel offset correction scheme utilizes “eye edge” samplers and demultiplexers already present and essential for operation of the CDR algorithm, and adds only simple word-rate logic, with no new analog circuitry. The result is the ability to precisely determine the offset polarity as well as to get an approximate immediate measure of the offset magnitude. The offset detected includes all of the analog circuitry in the channel, including the samplers themselves.10-25-2012
20110033014RECEIVER FOR DETECTING SIGNALS IN THE PRESENCE OF HIGH POWER INTERFERENCE - A RF receiver that comprises: (i) a complex mixer for converting a version of the RF signal to a complex baseband signal comprising an in-phase component and a quadrature component; (ii) one or more analog-to-digital converters (ADCs) connected to the complex mixer for digitizing the in-phase component and the quadrature component of the complex baseband signal; and (iii) a digital signal processor (DSP) connected the one or more ADCs. The DSP is programmed to mitigate interference in the complex baseband signal by a process that comprises the steps of: (i) performing at least one cross correlation operation involving L-length segments of the digitized in-phase and quadrature components of the complex baseband signal; and (ii) concatenating the cross-correlated L-length segments of the digitized in-phase and quadrature components of the complex baseband signal to produce digitized interference mitigated in-phase and quadrature components of the complex baseband signal.02-10-2011
20110235759Systems and Methods for Implementing a Multi-Sensor Receiver in a DSM3 Environment - In accordance with one embodiment, a method is implemented in a vectored system for improving a signal-to-noise ratio (SNR) of a far end transmitted signal on a victim line in the system. The method comprises mitigating, by the vectored system, self-induced far-end crosstalk (self-FEXT) on the victim line based on self-FEXT mitigation coefficients and receiving, by a second sensor, information relating to at least one of: self-FEXT of the vectored system, external noise, and the far end transmitted signal. The method further comprises learning, at the second sensor, coefficients relating to self-FEXT coupling into the second sensor and removing self-FEXT from the second sensor based on the learned coefficients. Upon removal of self-FEXT from the second sensor, a linear combiner configured to combine information relating to the victim line and the second line is learned. The method further comprises applying the learned linear combiner and readjusting the self-FEXT mitigation coefficients to remove any residual self-FEXT on the victim line after application of the learned linear combiner.09-29-2011
20110103530METHOD AND SYSTEM FOR COMPENSATION OF INTERFERENCE CANCELLATION DELAY - Aspects of a method and system for compensation of interference cancellation delay are provided. In this regard, a wireless communication device may receive one or more signals and may be operable to select, whether dynamically or statically, a processing path for processing the one or more received signals. The selected processing path may comprise one of an interference cancellation processing path and a pass-through processing path. A delay introduced by the pass-through processing path may be approximately equal to a processing delay introduced by the interference cancellation processing path. The one or more received signals may comprise HSDPA signals. The selection of processing path may be based on a measure of interference present in the one or more received signals.05-05-2011
20110280351APPARATUS AND METHOD FOR COMPENSATING FOR PHASE NOISE IN A RECEIVER SUPPORTING OFDM - An apparatus and method for compensating for phase noise in a receiver supporting Orthogonal Frequency Division Multiplexing (OFDM) by receiving a frequency-domain recovered signal and a time-domain received signal, estimating an average phase noise for each of the partial blocks of the signals, calculating an overall average phase noise using the average phase noises of the partial blocks, and removing the phase noise from the time-domain received signal using the calculated total average phase noise.11-17-2011
20100150286METHOD AND APPARATUS FOR EXCISION OF NARROWBAND INTERFERENCE SIGNALS IN NAVIGATION OR COMMUNICATION BANDS - A method for suppressing narrowband interference signals is provided. The method comprises inputting a digitized signal to a fast Fourier transform (FFT) to produce a plurality of contiguous frequency bins, examining said frequency bins to identify those bins containing narrowband interference above an excision threshold as excise bins, excising said excise bins to leave residual bins, implementing a lower resolution FFT analysis receiver to monitor broadband components and to mask out the narrowband interference excised in the excising step, reconstructing the signal with said residual bins using an inverse fast Fourier transform (IFFT), and outputting said reconstructed signal to a receiver as a protected signal having improved signal characteristics through reduced narrowband interference. The protected signal is used to produce enhanced operation in said receiver.06-17-2010
20100278290TRAFFIC-TO-PILOT RATIO ESTIMATION FOR MIMO-OFDM SYSTEM - A method for estimating a traffic-to-pilot ratio (TPR) for a received signal is disclosed. The received signal is despatialized to obtain a despatialized received signal. A channel matrix is despatialized to obtain a despatialized channel matrix. The despatialized received signal is whitened to obtain a pre-whitened despatialized received signal. The despatialized channel matrix is whitened to obtain a pre-whitened despatialized channel matrix. The estimated TPR for the received signal is determined using the pre-whitened despatialized received signal and one or more pre-whitened despatialized channel estimation coefficients.11-04-2010
20090022254PHYSICAL CARRIER TO INTERFERENCE-PLUS-NOISE RATIO TECHNIQUES FOR WIDEBAND WIRELESS COMMUNICATION NETWORKS - Techniques are provided to compute the physical carrier to interference-plus-noise ratio (PCINR) in a wireless communication system. In one embodiment, the PCINR is computed from received signals in active subcarriers in a preamble of a wireless transmission frame. In another embodiment, the PCINR is computed from a block of contiguous subcarriers in a symbol of received wireless transmission. The PCINR may be used to adjust a system parameter associated with wireless communication between wireless communication devices.01-22-2009
20090086861INTERFERENCE MANAGEMENT UTILIZING POWER AND ATTENUATION PROFILES - Interference that occurs during wireless communication may be managed through the use of fractional reuse and other techniques. In some aspects fractional reuse may relate to HARQ interlaces, portions of a timeslot, frequency spectrum, and spreading codes. Interference may be managed through the use of a transmit power profile and/or an attenuation profile. Interference also may be managed through the use of power management-related techniques.04-02-2009
20120099683DEMODULATION DEVICE - There is provided a demodulation device including: a demodulation unit demodulating an input signal to thereby output a signal of IQ coordinates; and a first noise elimination circuit eliminating a noise in the signal of the IQ coordinates that is output from the demodulation unit, in which the first noise elimination circuit includes: a first subtracter subtracting a first noise replica signal from the signal of the IQ coordinates that is output from the demodulation unit; an error information generation unit calculating error information of an output signal of the first subtracter to an ideal signal point of the IQ coordinates; a first frequency detection unit detecting a frequency of the noise based on the error information; and a first amplitude adjusting unit adjusting an amplitude of the first noise replica signal based on the error information and the frequency of the noise detected in the first frequency detection unit to output the first noise replica signal to the first subtracter.04-26-2012
20110293052MOBILE OFDM RECEIVER - A receiver is provided, in particular a mobile Orthogonal Frequency Division (OFDM) receiver, wherein the receiver comprises a receiving unit for receiving a multicarrier signal via a transmitting channel, a channel estimation unit for estimating a channel estimation signal indicative of properties of the transmitting channel based on the multicarrier signal and a feedback provided at a position of a signal processing path of the receiver downstream of the channel estimation unit, and a compensation unit adapted for at least partially compensating signal distortions within the transmitting channel on basis of the multicarrier signal received by the receiving unit and the channel estimation signal estimated by the channel estimation unit, and for outputting the received multicarrier signal with at least partially compensated signal distortions.12-01-2011
20100303182WIDEBAND INTERFERENCE MITIGATION FOR DEVICES WITH MULTIPLE RECEIVERS - Certain disclosed embodiments pertain to suppressing interference in a wireless communication system. For example, a method of suppressing interference can include receiving one or more first signals including components from a plurality of sub-channels. Each of the first signals can be converted into a respective plurality of first sub-band frequency components. A respective spatial filter can be determined for each frequency sub-band using one or more corresponding first sub-band components for each respective spatial filter. One or more second signals including components from the plurality of sub-channels can be received. Each of the second signals can be converted into a respective plurality of second sub-band frequency components. A corresponding plurality of filtered sub-band components can be generated by applying the respective spatial filters to the corresponding second sub-band components for each of the second signals.12-02-2010
20110293051RECEIVING DEVICE, LINEARIZER, AND DISTORTION COMPENSATION METHOD - A receiving device which receives a signal transmitted from a transmitting device by using a power amplifier, the receiving device includes a calculating unit which performs distortion compensation on a symbol included in a reception signal, a delay unit which holds a signal for a result from the distortion compensation, and the calculating unit performing the distortion compensation on a second symbol at a timing later than a first symbol based on a coefficient corresponding to an amplification characteristic of the power amplifier and on the signal for the result from the distortion compensation with respect to the first symbol held by the delay unit.12-01-2011
20110293050CHANNEL ESTIMATION IN OFDM TRANSMISSION SYSTEM AND METHOD - A system and method is provided for estimating the channel in OFDM transmission with inter-carrier interference (ICI). A channel in a data subcarrier in a subchannel shared between pilot subcarriers and data subcarriers can be estimated by performing interpolation based on estimated channels in pilot subcarriers in the same OFDM symbol as the subcarrier, such as through spline interpolation. A second estimate of the channel in the subcarrier can be produced by averaging an estimate of the channel in a subcarrier in the subchannel in a previous OFDM symbol and an estimate of the channel in a subcarrier in the subchannel in a succeeding OFDM symbol. A third estimate of the channel in the subcarrier can be produced through a linear combination of the first estimate and the second estimate. The channel in data subcarriers can be estimated through a weighted sum of the channel in nearest subcarriers.12-01-2011
20110286559INTERFERENCE CANCELLATION - There is provided a first device for use in a communication system, the communication system further comprising a plurality of second devices divided into a plurality of groups, the system having a plurality of orthogonal frequency carriers available for transmissions, each second device having a respective carrier frequency offset estimated from signals received from the first device, each of the second devices transmitting a respective stream of symbols using the respective estimated carrier frequency offset and one or more frequency carriers selected from the plurality of orthogonal frequency carriers, the first device comprising receiver circuitry for receiving respective signals from each of the second devices; a channel estimator for generating, from the received signals, an estimate of the channel over which the signals have been transmitted; an interference estimator for generating, from the received signals, an estimate of interference at the first device caused by errors in the carrier frequency offsets estimated by each second device; first circuitry for cancelling interference in the signals received at the first device using the estimate of the interference, the circuitry being configured to cancel interference between second devices within a first one of the plurality of groups; second circuitry for equalising the signals output from the first circuitry using the estimate of the channel; and third circuitry for cancelling interference in the signals output from the second circuitry, the third circuitry being configured to cancel the interference between second devices in a second one of the plurality of groups.11-24-2011
20110286558APPARATUS 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
20120236975RADIO RECEIVER AND METHOD FOR CONTROLLING RADIO RECEIVER - According to one embodiment, a radio receiver includes an antenna, a low-noise amplifier (LNA), a quadrature demodulator, an analog-to-digital converter (ADC), first and second power calculators, a correlation value calculator, a correction parameter generator, a corrector, a demodulator, and a controller. The antenna receives a signal. The LNA amplifies the received signal. The quadrature demodulator demodulates the amplified signal. The ADC converts analog IQ into digital IQ. The first and second power calculators calculate the first and second powers, respectively. The correlation value calculator calculates a correlation value between the digital IQ. The correction parameter generator generates a correction parameter based on the first and second power expected values, and the correlation value between the digital IQ. The corrector performs a linear transform operation. The demodulator demodulates the corrected IQ. The controller generates a gain control signal. The LNA is operated on the basis of the gain control signal.09-20-2012
20100266077METHODS AND SYSTEMS WITH SIMPLIFIED DOPPLER SPREAD CLASSIFICATION - Certain embodiments of the present disclosure propose methods and systems for classifying the Doppler spread based on the output of the frequency-tracking loop (FTL) discriminator in WiMAX systems to improve the performance of the channel estimation. The Doppler spread may be classified as low, medium or high based on the statistics of the output of the discriminator in the fine-tracking mode.10-21-2010
20080240313Closed Loop Adaptive Clock RFI Mitigation - A method according to one embodiment for mitigating radio frequency interference by identifying system clocks, identifying active radio channels, measuring clock harmonics in or near the active radio channels, determining potential interference occurring if the clocks were moved to new fundamental frequencies, and shifting clock fundamental frequencies to reduce interference to the active radio channels based on existing interference and the potential interference of a plurality of new fundamental frequencies. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.10-02-2008
20100034328SIGNAL RECEIVING APPARATUS, BROADCAST RECEIVING APPARATUS AND SIGNAL PROCESSING METHOD USING THE SAME - A signal receiving apparatus, a broadcast receiving apparatus and a signal processing method using the same are provided. An amplifying unit amplifies a received signal. A digital demodulating unit demodulates a signal amplified and output from the amplifying unit and extracts a transfer stream of the demodulated signal. A control unit controls on and off states of the amplifying unit. Accordingly, even a signal of high level of magnitude can be amplified if the signal has degrading quality.02-11-2010
20100027725NOISE-CANCELING FREQUENCY-TO-DIGITAL CONVERTERS - Methods and apparatuses for reducing noise in frequency to digital converters (FDCs). An FDC apparatus includes a first FDC, a second FDC and a combiner. The first and second FDCs are configured to independently sample an input signal according to a sample clock to generate first and second digital signals, each representing the instantaneous frequency of the input signal. The combiner is configured to form a resultant digital signal from the first and second digital signals. The first and second FDCs are designed and combined in the noise-canceling FDC apparatus so that the first and second signals they generate have correlated noise profiles in a frequency range of interest. When combined by the combiner to form the resultant digital signal, the resultant digital signal has a signal power to noise power ratio greater than the signal power to noise power ratios characterizing the first and second digital signals of the individual first and second FDCs.02-04-2010
20090147893INTERFERENCE SUPPRESSION METHOD AND INTERFERENCE SUPPRESSION DEVICE - A reception station 06-11-2009
20090147892METHOD AND APPARATUS FOR CANCELING INTERFERENCE - An apparatus for canceling interference includes a plurality of converters, a plurality of interference cancellation units, a plurality of variance detectors, and an output selecting unit. The plurality of converters converts a plurality of received signals to a plurality of frequency domain signals, respectively. The plurality of interference cancellation units cancel interference in the plurality of frequency domain signals using a plurality of interference cancellation schemes to generate a plurality of interference-canceled signals corresponding to the plurality of interference cancellation schemes, respectively. The plurality of variance detectors measure a plurality of amounts of residual interference corresponding to the plurality of interference-canceled signals, respectively. The output selecting unit selects a single interference-canceled signal with the least amount of residual interference from the plurality of interference-canceled signals, based on the plurality of amounts of residual interference.06-11-2009
20090285342PERTURBED DECODER, PERTURBED DECODING METHOD AND APPARATUS IN COMMUNICATION SYSTEM USING THE SAME - A decoder adopted to receive a signal transmitted in a communication system, includes one or more of a module adopted to pre-process a received signal to reduce the effect of interference-plus-noise on the received signal before filtering the received signal, and a module adopted to post-process the result of filtering the received signal.11-19-2009
20090310724INTERFERENCE MITIGATION FOR DEVICES WITH MULTIPLE RECEIVERS - Methods and systems for mitigating interference or estimating a covariance matrix in a communication system are disclosed. In some embodiments, a method of demodulating a received signal in a communication system includes receiving a first plurality of waveforms, estimating a covariance matrix based on the first plurality of waveforms, determining a spatial filter based on the estimated covariance matrix, receiving a second plurality of waveforms, generating at least one filtered waveform by applying the spatial filter to the second plurality of waveforms, and demodulating the at least one filtered waveform.12-17-2009
20120189085MULTI-SYMBOL PHASE OFFSET ESTIMATION - Receivers typically detect the presence of a pilot tone, transmitted as part of an RF signal, and use the pilot tone as a reference to detect symbols in the received RF signal. However, improper synchronization between the transmitter and the receiver units can result in timing offset and carrier frequency offset in the digitized received RF signal, impair the orthogonality between OFDM sub-carriers, and cause inter-carrier interference. Phase offsets caused by carrier frequency offset and timing offset can also degrade receiver performance. Functionality can be incorporated to estimate the phase offset over multiple symbols. Estimating the phase offset over multiple symbols in the received RF signal can lower the error rate. Correcting the phase offset in the received RF signal can ensure accurate sampling of the received signal, accurate channel estimates, and accurate decoding of the digitized received signal. This can minimize receiver performance degradation.07-26-2012
20100158170METHODS AND SYSTEMS USING FFT WINDOW TRACKING ALGORITHM - Techniques for the adjustment of a position of Fast Fourier Transform (FFT) window are provided. The adjustment may be based on the condition that the length of channel impulse response is larger than the length of cyclic prefix. The technique may determine a position of the FFT window that attempts to maximize carrier-to-noise (C/N) ratio value measured at the receiver.06-24-2010
20090207956RECEIVER, INTEGRATED CIRCUIT, AND RECEPTION METHOD - Channel characteristic calculation unit 08-20-2009
20090285341Joint channel estimator for synchronous and asynchronous interference suppression in SAIC receiver - This invention discloses improved single antenna interference cancellation (SAIC) receivers utilizing joint channel estimation for suppression of interference of co-channel signals. This invention describes the technique to perform joint channel estimation for either synchronous or asynchronous co-channel signals without a prior knowledge of the interfering training sequence or its timing position. The invented joint channel estimation can require initial detection of the desired signal and can be implemented as a multistage equalization structure.11-19-2009
20090086863INTERFERENCE DETECTION AND MITIGATION - Techniques for detecting and mitigating interference are described. A device (e.g., a cellular phone) senses interference levels and digitally reconstructs the expected interference in the received signal. The device may correlate the reconstructed interference with the received signal and determine interference in the received signal based on correlation results. The device may adjust the operation of one or more circuit blocks (e.g., a mixer, an LNA, etc.) in a receiver based on the detected interference in the received signal. Alternatively or additionally, the device may condition the digital interference to obtain conditioned reconstructed interference matching the interference in the received signal and may then subtract the conditioned interference from the received signal.04-02-2009
20100080328RECEIVER ACTIONS AND IMPLEMENTATIONS FOR EFFICIENT MEDIA HANDLING - A receiver includes a detector for detecting a change in source of incoming media during an on-going communication session, and means to provide a reset signal in order to reset decoder states of a decoder in response to such a detected change before decoding new incoming media. In this way, a state mismatch can be avoided without the need for several active decoder instances in the receiver, leading to substantial savings with respect to overall complexity, memory usage and power consumption. This also means that media distortions can be eliminated or at least reduced when the decoded media is finally rendered by a player.04-01-2010
20100086088OPTIMIZED FINGER ASSIGNMENT FOR IMPROVED MULTICARRIER THROUGHPUT - Systems and methodologies are described that facilitate dynamically allocating demodulation resources of a wideband receiver to provide improved demodulation of simultaneously received signals. Signal-to-noise ratio (SNR) and/or packet error rate (PER) can be measured for the plurality of carriers to determine which demodulators related to the carriers require more resources than others to demodulate signals at a specified signal quality. Where the SNR of a related carrier is high and/or PER is low, the demodulator can require fewer resources than where the SNR of a related carrier is low and/or PER is high. In this regard, the resources are dynamically allocated among the demodulators and reallocated where SNR/PER changes and/or additional resources are made available.04-08-2010
20100086087Transmission Enhancements for Physical Layer Transmission - Aspects of the invention provide apparatuses, computer media, and methods for supporting the broadcast of signaling data over a network. Error detection and protection as well as modulation mechanisms enhance the flexibility and robustness of signaling data for digital video broadcasting. A first error detection code for a first portion of signaling data and a second error detection code for a second portion of the signaling data are determined. The signaling data is combined with data and transmitted as a digital stream through a digital terrestrial television broadcasting system. A portion of the signaling data may include a configurable part and a dynamic part or may include different dynamic parts of the signaling data. Different portions of the signaling data may be separately modulated and encoded. A portion of the signaling data may be divided over a plurality of code words and evenly distributed over a transmission period.04-08-2010
20120106685SIGNAL PROCESSING APPARATUS AND RELATED METHOD FOR GENERATING TARGET ESTIMATED SIGNAL OF SPECIFIC SIGNAL COMPONENT IN INPUT SIGNAL - A signal processing apparatus includes a signal generating block arranged to generate a target estimated signal of a specific signal component in an input signal. The signal generating block includes a reference signal generating circuit, a signal processing circuit, and a signal adjusting circuit. The reference signal generating circuit is arranged to generate a reference estimated signal for the specific signal component in the input signal. The signal processing circuit is coupled to the reference signal generating circuit, and arranged to process the reference estimated signal and accordingly generate a signal processing result. The signal adjusting circuit is coupled to the signal processing circuit and the reference signal generating circuit, and arranged to output the target estimated signal by adjusting the reference estimated signal according to the signal processing result.05-03-2012
20110170642APPARATUSES, METHODS AND COMPUTER PROGRAMS FOR CONVEYING INFORMATION - The invention is related to an apparatus comprising: a receiver configured to receive a channel quality indication matrix; a processor configured to repeat, until the channel quality indication matrix is empty except for selected scheduling results, the following procedure: selecting a column of the channel quality indication matrix having the smallest number of non-zero channel quality indicators; searching for a largest channel quality indicator in the selected column of the channel quality indication matrix; selecting the searched largest channel quality indicator as a scheduling result, and emptying the column and row of the channel quality indication matrix corresponding to the selected scheduling result except for the selected scheduling result.07-14-2011
20090274252Delay Restricted Channel Estimation for Multi-Carrier Systems - A method is disclosed that includes channel estimation for a multi-carrier modulation of a plurality of subcarriers. The method includes performing a first channel estimation to obtain a first estimate of a channel based on a received signal. The method further includes suppressing a portion of elements of the first estimate of the channel to obtain a suppressed estimate of the channel. The method also includes multiplying the suppressed estimate of the channel by a first matrix to obtain a delay restricted estimate of the channel.11-05-2009
20100220824ITERATIVE INTERFERENCE CANCELLATION USING MIXED FEEDBACK WEIGHTS AND STABILIZING STEP SIZES - A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).09-02-2010
20090103669Adaptive equalization and interference cancellation with time-varying noise and/or interference - A method and apparatus is disclosed to compensate for interference and/or distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions. A communications receiver includes a noise analyzer to characterize the composition of the interference and/or the distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions. The noise analyzer produces a selection signal indicating the composition of the interference and/or the distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions to be used by the communications receiver. In an exemplary embodiment, the communications receiver selects at least one set of equalization coefficients and/or updates at least one parameter of a least-squares algorithm or the suitable equivalent algorithm to compensate for the interference and/or the distortion impressed onto a transmitted communication signal in the presence of a particular time-varying noise and/or interference condition. In another exemplary embodiment, the communications receiver selects a corresponding adaptive equalizer from an adaptive equalizer bank to compensate for the interference and/or the distortion impressed onto a transmitted communication signal in the presence of the particular time-varying noise and/or interference condition.04-23-2009
20090041168HARMONICS AVOIDANCE - Systems, methods, devices, and processors are described for a wireless receiver. The receiver may be configured to receive signals transmitted according to various mobile digital television standards. The receiver may include a number of hardware engines. The hardware engines may be individually controlled in a number of aspects. Power to particular hardware engines may be controlled, and the speed of the different hardware engines may vary. The receiver may include a novel multi-function decoder engine. The receiver may be configured to dynamically avoid problems related to harmonics, and may include a novel tap configuration with taps at different locations in the data flow.02-12-2009
20110206167Data-Aided SIR Estimation - A signal-to-interference estimate is generated using unknown data symbols in place of or in addition to pilot symbols. Data received over a data channel (traffic channel or control channel) are collected. The data symbols are then used to compute an observation metric based on deviations of the data symbols from a predetermined set of possible data symbols, wherein one of the data symbols and symbol constellation is normalized. A data channel signal-to-interference ratio is then computed based on the observation metric.08-25-2011
20110200151Iterative Interference Suppression Using Mixed Feedback Weights and Stabilizing Step Sizes - A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).08-18-2011
20080212723SIGNAL PROCESSING APPARATUS, SIGNAL PROCESSING METHOD, AND PROGRAM - In a signal processing apparatus adapted to process a signal transmitted via a transmission path, distortion of a waveform of a signal value of a specific symbol is predicted on the basis of a characteristic of distortion depending on values of symbols transmitted before the specific symbol, and the distortion is removed from the waveform of the received signal thereby producing a distortion-removed waveform. A comparison value is calculated for each allowable value of the specific symbol by subtracting a predicted signal value of the specific value from the distortion-removed waveform. A symbol value corresponding to the smallest comparison value is determined as the value of the specific symbol. An error suspicion level value indicating the degree of suspicion of being incorrect is calculated for each of the predetermined number of symbols, and already determined values of symbols are corrected in accordance with the error suspicion level values.09-04-2008
20080212725Digital Predistortion for Cognitive Radio - Embodiments of cognitive radio technology can recover and utilize under-utilized portions of statically-allocated radio-frequency spectrum. A plurality of sensing methods can be employed. Transmission power control can be responsive to adjacent channel measurements. Digital pre-distortion techniques can enhance performance. Embodiments of a high DNR transceiver architecture can be employed.09-04-2008
20100278289MULTISTAGE CHANNEL ESTIMATION METHOD AND APPARATUS - A multistage channel estimation method and apparatus is provided. The multistage channel estimation method includes: receiving a data frame to compensate for a distortion of the data frame based on a first channel estimation value associated with a corresponding section of the data frame; a first step of changing the corresponding section to calculate a second channel estimation value associated with the changed section; a second step of updating the first channel estimation value based on the calculated second channel estimation value; a third step of compensating for the distortion of the data frame based on the updated first channel estimation value to count a number of compensations; and repeating the first step through the third step, when the counted number of compensations does not match a predetermined numerical value.11-04-2010
20100061494APPARATUS AND METHDO FOR CANCELING INTER-ANTENNA INTERFERENCE OF ORTHOGONALLY CODED SIGNALS - An apparatus and a method for canceling inter-antenna interference are provided. The apparatus to cancel inter-antenna interference includes a reception unit to receive, from a transmitter, first data and second data orthogonally coded with the first data, and to generate a received vector including the first data and the second data, a channel estimation unit to generate a channel state matrix with respect to a radio channel from a plurality of transmission antennas of the transmitter to the reception unit, a detection unit to detect the first data based on the channel state matrix and the received vector, a pseudo interference signal-generation unit to generate pseudo interference signals based on the channel state matrix and the detected first data, and an interference signal-canceling unit to cancel the pseudo interference signals from the received vector.03-11-2010
20090168930Methods and Systems for Doppler Estimation and Adaptive Channel Filtering in a Communication System - A method for Doppler shift estimation for channel estimation of a received signal, comprising the steps of: calculating time domain correlations; providing a Hamming window over the calculated time domain correlations; calculating a power spectrum by using FFT; calculating an adaptive threshold based on a noise floor and an average power density calculated from the power spectrum; and estimating a Doppler shift based on the adaptive threshold.07-02-2009
20090097598MULTIPLE INPUT MULTIPLE OUTPUT (MIMO) RECEIVER AND SIGNAL DETECTION METHOD THEREOF - A Multiple Input Multiple Output (MIMO) receiver and a signal detection method thereof are provided. Since no square root calculation needs to be performed when a calculation for detecting a transmission signal is performed using a Zero Forcing-Sorted QR Decomposition (ZF-SQRD) algorithm and a Minimum Mean Square Error-Sorted QR Decomposition (MMSE-SQRD) algorithm, the complexity of a calculation for detecting a transmission signal under a MIMO channel environment can be reduced.04-16-2009
20100128827MMSE Demodulation in a Multi-User MIMO System - A method and apparatus is provided for demodulating a desired data stream in a MU-MIMO communication system where only the precoder for the desired data stream is known a priori. The receiving terminal according to various embodiments of the present invention estimates the precoder for one or more interfering data streams. The receiving terminal can then use the known precoder for the desired data stream and the estimated precoders for the interfering data streams to perform MMSE demodulation.05-27-2010
20090168929METHOD AND APPARATUS FOR IMPULSE NOISE DETECTION AND SUPPRESSION FOR DVB-T - A method and apparatus for adaptive impulse noise detection and suppression (INDS) where information regarding detected impulse noise (IN) pulses is used to adjust detection and suppression parameters. To decrease the rate of false detection, groups of samples, instead of individual samples, of the digitized received signal are used to detect the presence of IN pulses. The method and apparatus for adaptive INDS may be used in communication systems employing single-carrier or multi-carrier modulation schemes, and is preferably used for Orthogonal Frequency Division Multiplexing (OFDM) modulation. The proposed adaptive INDS systems may be used to effectively reduce the effects of impulse noise and improve the quality of received signals.07-02-2009
20080273638Reducing the Effect of Noise in a Multi-Channel Telecommunication Receiver - A telecommunication receiver provided according to the present invention is implemented to receive a first signal containing information and noise on a first set of sensors and a second signal containing only noise on a second set of sensors. Receiver then decodes the information using first signal and second signal. In one embodiment, a bonded DSL receiver with k signals sensors is implemented with additional s number of noise only sensors to receive only noise. Accordingly, joint demodulation is performed using signals received on k signals sensors and s noise only sensors. The noise sensor is implemented in common mode.11-06-2008
20080279317BICM DECODING IN THE PRESENCE OF CO-CHANNEL INTERFERENCE - Systems and methods are provided for computing soft information for digital information based on a received signal, where the received signal suffers from noise and interference. A receiver that decodes the received signal may estimate channel information, such as the channel gain, associated with the interfering source. The receiver may also obtain modulation information through a backbone network or by decoding control information transmitted by the interfering source. Using the modulation information and the channel information, the receiver may estimate the effect that interference has on the received signal, and may compute soft information (e.g., a log-likelihood ratio) for the digital information.11-13-2008
20080285692METHOD AND APPARATUS FOR PARALLEL MIDAMBLE CANCELLATION - Method and apparatus for performing midamble cancellation to remove midamble interference from the convolution tail of data field 11-20-2008
20080292034Arrangements for interference mitigation utilizing recursive estimation - A method is disclosed that includes receiving a signal having a data vector component and an interfering component and creating a first set of digitized data that represents the interfering component. The method can also generate a polynomial equation based on the first set of digitized data and generate a second set of digitized data that represents a data vector component of the received signal. The polynomial equation can be subtracted from the received signal to cancel at least a portion of the interfering component and provide an interference mitigated signal representing the data vector component. An error in the interference mitigated signal can be determined and the interference mitigated component can be recalculated based on the error. Other embodiments are also disclosed.11-27-2008
20080292032Arrangements for interference mitigation utilizing estimation - A method is disclosed for interference mitigation which can include receiving a signal having a data component, an interfering component and a time period and creating a first plurality of digitized data that represents at least a portion of the interfering component. The method can also include generating a polynomial equation that is related to the at least a portion of the interfering component and generating a second plurality of digital data that represents a data vector of the received signal. The method can further subtract the polynomial equation from the received signal to cancel at least a portion of the interfering component to provide an interference mitigated signal representing the data component.11-27-2008
20100135442Adaptive offset adjustment algorithm - An apparatus and method is disclosed to compensate for one or more offsets in a communications signal. A communications receiver may carry out an offset adjustment algorithm to compensate for the one or more offsets. An initial search procedure determines one or more signal metric maps for one or more selected offset adjustment corrections from the one or more offset adjustment corrections. The offset adjustment algorithm determines one or more optimal points for one or more selected offset adjustment correction based upon the one or more signal maps. The adaptive offset algorithm adjusts each of the one or more selected offset adjustment corrections to their respective optimal points and/or each of one or more non-selected offset adjustment corrections to a corresponding one of a plurality of possible offset corrections to provide one or more adjusted offset adjustment corrections. A tracking mode procedure optimizes the one or more adjusted offset adjustment corrections.06-03-2010
20080240314CHANNEL ESTIMATION WITH EFFECTIVE CO-CHANNEL INTERFERENCE SUPPRESSION - A method for a wireless communication system is provided. The method includes isolating a set of pilot signals, where the pilot signals are associated with multiple base stations or multiple sectors of a single base station. This includes nulling a subset of the pilot signals to mitigate co-channel interference and to perform channel estimation in accordance with at least one of the pilot signals.10-02-2008
20110206170CODE BLOCK INTERFERENCE CANCELLATION - Certain aspects of the present disclosure propose an interference cancellation method based on the sub-blocks inside a block. For example, in the long term evolution (LTE) standard, the sub-blocks may be code blocks and the blocks may be transport block.08-25-2011
20110206169Methods and Apparatus for Enhancing Channel Estimation - A noisy frequency-domain channel estimate enhancer includes an over-sampler configured to transform the noisy frequency-domain channel estimate into a time-domain channel estimate that is virtually over-sampled by an integer factor m. The over-sampler is connected to a de-interleaver configured to divide the time-domain channel estimate into m de-interleaved sub-vectors. The de-interleaver is connected to a suppressor configured to suppress noisy taps from each de-interleaved sub-vectors to form m noise suppressed sub-vectors. The suppressor is connected to a selector configured to select a noise suppressed sub-vector associated with a highest signal-to-noise ratio. The selector is connected to a discrete Fourier transformer configured to transform the selected noise suppressed sub-vector into a noise suppressed preliminary frequency-domain channel estimate. The discrete Fourier transformer is connected to a phase-shifter configured to phase-adjust the taps of the noise suppressed preliminary frequency-domain channel estimate to form an enhanced frequency-domain channel estimate.08-25-2011
20090185648METHODS AND DEVICES FOR PROCESSING SIGNALS TRANSMITTED VIA COMMUNICATION SYSTEM - A method for processing signals transmitted via a communication system includes: measuring a first parameter associated with a signal power of a first frequency band of a received signal; measuring a second parameter associated with a signal power of a second frequency band of the received signal, wherein the first frequency band and the second frequency band are overlapped; comparing the first parameter with the second parameter to generate a comparison result; and detecting whether co-channel interference (CCI) exists in the communication system according to the comparison result in order to generate a detection result.07-23-2009
20120069940PLATFORM NOISE ESTIMATION AND MITIGATION FOR WIRELESS RECEIVERS - An apparatus and method suitable to estimate impairments of wireless signals, including both noise and interference of the wireless signals are disclosed herein. The noise of the wireless signals may be caused by thermal noise and platform noise. An adaptive scheme may dynamically switch between estimating interference only or the combined noise and interference. Other embodiments may be disclosed or claimed.03-22-2012
20110222639METHOD AND/OR SYSTEM FOR ESTIMATING PHASE ERROR NOISE - Embodiments of methods and/or systems for estimating phase error noise are disclosed.09-15-2011
20110222638FREQUENCY-DEPENDENT IQ IMBALANCE ESTIMATION - RF impairment parameters, including frequency-dependent IQ imbalance, are estimated in a wideband received signal on a per-sub-band (or per sub-band pair) basis. In one embodiment, block-type pilot signals are received, such as on SCH, and IQ imbalance and carrier frequency offset are estimated from the block-type pilot signals. The block-type pilot signals may be received in only one sub-band. Data and comb-type pilot signals are then received on all sub-bands. Phase noise and channel coefficients are estimated for the first sub-band, based on the IQ imbalance and carrier frequency offset estimates. IQ imbalance is then successively estimated, on a per-sub-band (or per sub-band pair) basis, based on the comb-type pilot signals, the previously estimated carrier frequency offset estimate, and the phase noise and IQ imbalance estimates from prior sub-bands (or pairs). This may comprise iterative estimation based on decision feedback.09-15-2011
20090080578PHASE NOISE LIMITING APPARATUS, PHASE NOISE LIMITING METHOD, RECEIVING APPARATUS, RECEIVING METHOD, AND PROGRAMS - Disclosed herein is a phase noise limiting apparatus including a detection section configured to detect a phase noise quantity from an input signal; a determination section configured such that furnished with a plurality of correspondence tables indicating parameters used for phase synchronization with the input signal, the determination section determines one of the parameters in keeping with the phase noise quantity detected by the detection section on the basis of one of the plurality of correspondence tables; and a phase noise limitation section configured to limit the phase noise in the input signal based on the parameter determined by the determination section.03-26-2009
20130216010MONOBIT RECEIVER SPURIOUS HARMONICS CONTROL METHOD AND SYSTEM - A method for minimizing unwanted signal harmonics from at least one signal in a channel received through a monobit receiver, comprising: conditioning (08-22-2013
20090086864INTERFERENCE DETECTION AND MITIGATION - Techniques for detecting and mitigating interference are described. A device (e.g., a cellular phone) senses interference levels and digitally reconstructs the expected interference in the received signal. The device may correlate the reconstructed interference with the received signal and determine interference in the received signal based on correlation results. The device may adjust the operation of one or more circuit blocks (e.g., a mixer, an LNA, etc.) in a receiver based on the detected interference in the received signal. Alternatively or additionally, the device may condition the digital interference to obtain conditioned reconstructed interference matching the interference in the received signal and may then subtract the conditioned interference from the received signal.04-02-2009
20090207955Adaptive Digital Filter, FM Receiver, Signal Processing Method, and Program - The adaptive digital filter of the present invention includes: a filter unit that includes a plurality of multipliers (08-20-2009
20090003497Digital signal processing device, digital signal processing method, and digital signal processing program - The present invention provides a digital signal processing device that considerably reduces a return noise generated in a processing result signal in specific signal processing without wastefully increasing the processing load. There is provided a digital signal processing device that executes specific signal processing under which a return noise is generated in a processing result signal which includes an up-sampling processing unit that performs the up-sampling processing for a digital signal with a predetermined up-sampling rate to generate an up-sampling signal, a specific signal processing unit that performs the specific signal processing for the up-sampling signal generated by the up-sampling processing unit to generate the processing result signal, and a down-sampling processing unit that performs the down-sampling processing for the processing result signal generated by the specific signal processing unit with a predetermined down-sampling rate to generate a down-sampling signal.01-01-2009
20110222637Method and Apparatus for Reducing the Contribution of Noise to Digitally Sampled Signals - A method and apparatus for reducing the contribution of noise to digitally sampled signals includes a statistical processor and a slope limiter. The statistical processor determines an average value (mean and/or standard deviation) of the filtered signal which is used to determine a slope limit corresponding to an expected maximum first derivative value of a target signal frequency. This slope limit is applied to constrain the output of an analog to digital converter, to prevent the output of the analog to digital converter from exceeding this maximum rate of rise or fall. By constraining the output of the analog to digital converter, it is possible to digitally sample analog signals without first utilizing an anti-aliasing filter, since the post processing of the digitally sampled signals limits the contribution of the higher frequency components of the signal to thereby enable a fully digital sampling and filtering circuit to be provided for receiving signals.09-15-2011
20090257535Method and Device for Compensating the Doppler Effect for a Digital Signal Receiver - The invention relates to a method of compensating the Doppler effect for a mobile receiver. This method consists in producing a phase-locked loop based on the signal to be demodulated to correct the frequency control of the tuner element and thus the drift due to the Doppler effect. The invention also relates to a receiver implementing this method.10-15-2009
20090245440OUTPUT CIRCUITRY FOR MINIMIZING SPURIOUS FREQUENCY CONTENT - A system including first voltage supply circuitry configured to provide a first voltage supply with spurious frequency content and second voltage supply circuitry configured to provide a second voltage supply without the spurious frequency content is provided. The system includes signal generation circuitry configured to generate a first digital signal using a clock signal and the first voltage supply and configured to cause the spurious frequency content on the first voltage supply and output circuitry configured to generate a second digital signal from the first digital signal synchronous with the clock signal using the second voltage supply.10-01-2009
20080260078Iterative Reception of a Multi-Carrier Signal With Interference Cancellation - A method is provided for the reception of a data signal comprising multiple carriers, known as a multi-carrier signal, which undergoes channel coding at transmission, said method employing an estimation of the received signal. One such reception method comprises at least one iteration for improving the estimation of the received signal, as a function of the received signal and of an estimation preceding from said received signal. One such iteration comprises, for each of the carriers of the received signal, a step involving the equalisation of the carrier with the cancellation of an interference affecting the received signal as a function of at least one statistical parameter of the estimation preceding from said received signal.10-23-2008
20080260077Method and Apparatus for Recognizing a Disturbing Effect in an Information Channel - In order to recognize a distorting effect in a serial communication channel, a set of different symbol vectors formed of n>=2 successive communication symbols and a set of reference values of a critical characteristic of the i-th communication symbol (10-23-2008
20090316841NULL DETECTION AND ERASURE DECODING FOR FREQUENCY SELECTIVE CHANNELS IN A BROADCASTING SYSTEM - A null detection and erasure decoding process for a frequency selective channel in a broadcasting system. An orthogonal frequency-division multiplexing (OFDM) receiver receives an input bitstream, determines a noise level of the received input bitstream, and then detects a null in the input bitstream based on the noise level. Once a null is detected, the presence of the null is signaled to a decoder, allowing the decoder to process the null as an erasure.12-24-2009
20090161805Detection Method of Space Domain Maximum Posteriori Probability in a Wireless Communication System - A detection method of space domain maximum posteriori probability (MAP) in a wireless communication system is a kind of detection technique of space domain MAP in a multi-aerial wireless communication system, which makes the detection of iteration soft interference elimination for the interference signals in the other moments, and makes the MAP detection or the simplified MAP detection for the all signals in current time and space domain. It includes the steps of: taking a fading block as a unit; the received signals are matched and combined in time domain and space domain, and calculating an equivalent channel matrix; making the sequence detection, calculating estimation and variance of the signals before the ending of detecting internal iteration; when the internal iteration detection finishes, the result is outputted, or is outputted after hard decision.06-25-2009
20100150287METHOD AND SYSTEM FOR DYNAMICALLY TUNING AND CALIBRATING AN ANTENNA USING ANTENNA HOPPING - Methods and systems for dynamically tuning and calibrating an antenna using antenna hopping are disclosed. In this regard, in a wireless device comprising an antenna that is configurable into a plurality of configurations, determining a subset of the configurations, where each configuration of the subset enables received signal strength above a threshold for a wireless channel, may be determined. During a time interval in which the wireless device is receiving signals on the wireless channel, the antenna may be configured to sequentially utilize each configuration of the subset. During the time interval, a plurality of samples of the wireless channel may be generated, where each of the samples corresponds to a different one of the configurations of the subset. The plurality of samples may be aggregated. The aggregated samples may be processed to recover information communicated on the wireless channel.06-17-2010
20090122929Apparatus and method for cancelling interferences between orthogonal coded signals in mobile communication system - Apparatuses and methods for cancelling interferences between signals are provided. The apparatuses includes: a receiving unit that receives an orthogonal coded signal from a transmitter and generates a received vector; a channel estimation unit that estimates a state of a wireless channel from the transmitter to the apparatus where the cancelling of the interference between signals is performed and generates a channel state matrix; a Q-R decomposition unit that performs Q-R decomposition with respect to the generated channel state matrix and generates a Q matrix and an R matrix, and generates a decision statistic vector based on the generated Q matrix and the received vector; and a signal determination unit that determines a received signal with interference from the orthogonal coded signal being decreased based on the generated decision statistics vector.05-14-2009
20090316843METHOD AND APPARATUS FOR PARALLEL MIDAMBLE CANCELLATION - Method and apparatus for performing midamble cancellation to remove midamble interference from the convolution tail of data field 12-24-2009
20090316842PHASE-NOISE RESILIENT GENERATION OF A CHANNEL QUALITY INDICATOR - System(s) and method(s) are provided for generating phase-noise resilient channel quality indicator(s). A pilot signal utilized to determine a channel quality indicator is rotated to be aligned to a phase reference signal. Separate noise evaluations in quadrature and in-phase directions are utilized, at least in part, to generate a net noise estimate that is phase-noise compensated or resilient. For example, various combination schemes of quadrature and in-phase noise evaluations can be exploited to generate a net noise estimate, the schemes include weighted average of in-phase and quadrature noise estimates and running averages thereof. Simulation of net noise estimates as a function of geometry conditions reveal that the combination schemes provide substantive mitigation of phase-noise, thus making CQI generation phase-noise resilient.12-24-2009
20090274251NOISE SUPPRESSING DEVICE - To provide a noise suppressing device which accurately suppresses weak electric field strength pulse noise.11-05-2009
20090116594RADIO RECEIVER - A radio receiver including a reception processing system that uses a discrete-time frequency conversion to acquire a signal having a sampling rate corresponding to a local frequency, wherein the reception characteristic is improved when the reception processing system is applied to a system having a wide reception channel band. The radio receiver (05-07-2009
20100183104Method and System for Communication in a Wireless Network - Methods and apparatus are described for processing data in a wireless communication network. Iterative estimation techniques are used to enable tracking of time-varying communication channels. A signal is transmitted over a channel in the network, the signal comprising a sequence of symbols carried on a plurality of sub-carriers. Boot-up estimator (07-22-2010
20100177856ITERATIVE INTERFERENCE CANCELLATION USING MIXED FEEDBACK WEIGHTS AND STABILIZING STEP SIZES - A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequencyselective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimates. Receiver embodiments may be implemented explicitly in software or programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user or subchannel symbol level).07-15-2010
20100177855Power Control Using Denoised Crosstalk Estimates in a Multi-Channel Communication System - An access node of a communication system is configured to generate denoised crosstalk estimates for respective channels of the system and to adjust power levels of signals transmitted over one or more of the channels based on the denoised crosstalk estimates. The access node obtains crosstalk estimates for the respective channels. The access node is configured to convert the crosstalk estimate for a given channel to a discrete transform domain, to substantially eliminate in the discrete transform domain one or more designated portions of the crosstalk estimate for the given channel, and to convert remaining portions of the crosstalk estimate for the given channel back from the discrete transform domain to obtain the corresponding denoised crosstalk estimate for the given channel. The access node may comprise one or more central offices of a DSL communication system.07-15-2010
20100215132Method and Apparatus for Allocating Processing Delays in Multi-Carrier Systems - A multi-carrier linear equalization receiver, e.g., a RAKE receiver or chip equalization receiver, is described herein. The multi-carrier receiver distributes processing delays among a plurality of received carriers based on a comparison between the signal-to-interference ratios (SIRs) determined for each carrier. The receiver initially allocates a minimum number of processing delays to each carrier. In one embodiment, any remaining additional processing delays are distributed evenly between the carriers when a comparison between the largest and smallest SIR is less than or equal to a threshold. In another embodiment, the remaining additional processing delays are distributed to favor the carrier(s) with the strongest SIR(s) when the comparison between the largest and smallest SIR exceeds the threshold. By distributing the additional processing delays to favor the carriers with the strongest SIRs, the embodiments of the present invention enable system designers to limit the total number of available processing delays without sacrificing performance.08-26-2010
20100254497COMMUNICATION DEVICE - Improving the accuracy of estimation of channel responses in receiving signals from a plurality of antennas is disclosed. A transmitting device of a base station includes a preamble A generating unit 10-07-2010
20100239056SIGNAL PROCESSING CIRCUIT - A test signal generating part (09-23-2010
20100254496NOISE POWER ESTIMATION METHOD AND DEVICE THEREOF - A noise power estimation method for estimation of channel state information in OFDM systems is provided. The noise power estimation method includes: calculating an evaluated noise power for a specific subcarrier of a current symbol; comparing a target threshold with the evaluated noise power to generate a comparison result; and determining a final noise power for estimating channel state information by adjusting the evaluated noise power according to the comparison result.10-07-2010
20080310562Efficient Covariance Computation by Table Lookup - The impairment processor described herein uses a look-up table operation to reduce the computational complexity associated with determining an impairment correlation between first and second sample streams for an interference rejection receiver. One exemplary impairment processor iteratively computes multiple partial impairment correlations based on values selected from look-up table(s), and combines the partial impairment correlations to obtain a final impairment correlation between the first and second sample streams. During each iteration, the impairment processor computes a pair of delay offsets corresponding to the respective processing and path delays of the first and second sample streams, computes an index value as a function of a difference between the pair of delay offsets, selects a pre-computed value from the look-up table based on the index value, determines a pulse correlation estimate based on the selected pre-computed value, and determines the partial impairment correlation for that iteration based on the pulse correlation estimate.12-18-2008
20110235760EFFICIENT OFDM PEAK REDUCTION ALGORITHM - An efficient method of OFDM peak reduction is described. In an embodiment, a set of the most significant peaks in a symbol of an OFDM signal are identified and then, for each identified peak, a shifted and scaled version of a template cancellation signal is subtracted from the OFDM signal. The template cancellation signal is shifted such that its peak aligns with the identified peak and it is scaled such that it has the opposite phase to the identified peak. No iterative peak search and cancellation is involved in peak reduction, i.e. a cancellation step is not followed by another peak search for the same OFDM symbol. The process is repeated for each symbol in turn and in some embodiments the OFDM signal is up-sampled before it is analyzed to identify the most significant peaks.09-29-2011
20100135443Variable time delay control structure for channel matching - A cosite interference cancellation system is provided for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath. The cosite interference cancellation system and associated method advantageously provide improved signal rejection by continuously controlling (adjusting) a matching time delay to reduce cosite interference.06-03-2010
20100266078RADIO COMMUNICATION DEVICE, AND RECEPTION QUALITY ESTIMATION METHOD - A radio base station 10-21-2010
20090245441ROBUST ITERATIVE LINEAR SYSTEM SOLVERS - In receiving equipment such as a mobile terminal (10-01-2009
20100220822INTER-CARRIER INTERFERENCE REDUCTION FOR MULTI-CARRIER SIGNALS - In mobile wireless communication systems the channel between the transmitter and receiver varies during a transmission. This is often referred to as fading, of which different kinds exist—each resulting in different impairments with specific properties. A low complexity scheme is described to reduce the noise created by inter-carrier interference or ICI. The method makes use of the guard interval and assumes slow variation of the channel. It is not restricted to wireless communication and can be used in any environment with varying channels.09-02-2010
20090141841INTERFERENCE NOISE ESTIMATION METHOD, RECEPTION PROCESSING METHOD, INTERFERENCE NOISE ESTIMATION APPARATUS, AND RECEIVER, IN MULTICARRIER COMMUNICATIONS SYSTEM - To make it possible to estimate interference noise power with high accuracy even when channel variations are present in the frequency domain and the time domain, average values between pilot signals received at different timing and at different frequencies are obtained and interference noise is estimated based on a difference between the average values.06-04-2009
20090129521SYSTEMS AND METHODS FOR INCREASING AUDIO SNR (SIGNAL TO NOISE RATIO) IN A DIGITAL SOUND DECODER - Systems and methods for increasing audio SNR in a NICAM digital sound decoder are provided. One method according to the invention includes receiving a scale factor that indicates a number of bits of a Near Instantaneous Companded Audio Multiplex (NICAM) signal that have been truncated from the signal. The method also includes receiving the NICAM signal itself. The NICAM signal may include a predetermined number of zero bits in place of the predetermined number of truncated bits. The method may also require appending a bit pattern to the NICAM signal that approximates a rounding of the NICAM signal. The bit pattern preferably includes at least one non-zero bit. Another method according to the invention may include selecting a bit pattern from a collection of bit patterns. The collection of bit patterns may include at least non-zero bit. The alternative embodiment of the invention may also include appending the selected bit pattern to the NICAM signal in order to replace a predetermined number of truncated bits.05-21-2009
20090161804Receiver window shaping in OFDM to mitigate narrowband interference - A receiver window for symbol extraction is provided. A symbol is spread across a plurality of sub-carriers of a frequency band for transmission. If the frequency band is affected by narrowband interference, the receiver window concentrates the narrowband interference energy to minimize its effect on distant sub-carriers within the frequency band. The receiver window is shaped for extracting the symbol from the frequency band, wherein the receiver window has a starting point before the start of the symbol. The receiver window overlaps a previous receiver window for the previous adjacent symbol on the same frequency band. The receiver window is shaped by overlapping and adding a channel impulse response segment from a zero-padded portion of the symbol to the beginning of the symbol and overlapping and adding a second portion from the previous zero-padded symbol (from the same frequency band) to the end of the symbol.06-25-2009
20090147891AUDIO SIGNAL DEMODULATION APPARATUS - An FM demodulation apparatus (06-11-2009
20080285691Wireless System With Hybrid Automatic Retransmission Request In Interference-Limited Communications - A wireless receiver (11-20-2008
20100220825SYSTEM AND METHOD FOR I/Q IMBALANCE COMPENSATION - A transmitter (09-02-2010
20100310023APPARATUS AND METHOD FOR ESTIMATING INVERSE CHANNEL OF REPEATER'S RECEIVING CHANNEL - Provided is an apparatus and method for estimating inverse channel of a repeater's receiving channel, which ensures stability and causality by generating a time-domain filter coefficient having information on an inverse channel of repeater's receiving channel from a signal transmitted from a main transmitter or another repeater. The apparatus includes: a channel estimator for estimating a channel established by a transmission path from a received signal; an inverse minimum phase filter coefficient generator for generating inverse channel of a minimum phase channel from the estimated channel, and converting the inverse channel of the minimum phase channel into a time-domain filter coefficient; an inverse group delay filter coefficient generator for generating a time-domain filter coefficient by using the estimated channel and the minimum phase channel; and a combiner for generating an inverse channel of a receiving channel in a time domain by combining the filter coefficient and the filter coefficient.12-09-2010
20130136217LOW JITTER 2-STAGE INTERFACE RECEIVER FOR LOW POWER APPLICATION - Disclosed herein is an interface receiver including: an input terminal receiving first and second data signals; a negative feedback unit negatively feeding back the first and second data signals input to the input terminal to generate first and second feedback signals; and an output terminal outputting logic level signals by using the first and second feedback signals generated by the negative feedback unit, whereby a timing margin can be secured.05-30-2013
20100310024Methods and systems for DSP-based receivers - Digital signal processing based methods and systems for receiving data signals include parallel receivers, multi-channel receivers, timing recovery schemes, and, without limitation, equalization schemes. 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. In an embodiment, a parallel DSP-based receiver in accordance with the invention includes a separate timing recovery loop for each ADC path. In an embodiment, a parallel DSP-based receiver includes a separate automatic gain control (AGC) loop for each ADC path. In an embodiment, a parallel DSP-based receiver includes a separate offset compensation loop for each ADC path. In an embodiment, the present invention is implemented as a multi-channel receiver that receives a plurality of data signals.12-09-2010
20100310025TRANSMITTING AND RECEIVING APPARATUSES AND METHODS - A transmitting apparatus which transmits a transmit symbol in orthogonal-frequency division multiplexing (OFDM) is disclosed. The transmitting apparatus includes a unit which provides a unicast channel; a unit which provides a multimedia broadcast multicast service (MBMS) channel; a unit which provides a specific pilot channel which is specific to a specified cell; a unit which provides one or more common pilot channels common to a plurality of cells; and a multiplexing unit which multiplexes the unicast channel, the MBMS channel, the specific pilot channel, and the one or more common pilot channels, and creates the transmit symbol, wherein the multiplexing unit time-division multiplexes, in the same frequency band, a unicast frame which includes the unicast channel, and an MBMS frame which includes the MBMS channel, and wherein an insertion density of the common pilot channel included in the MBMS frame is larger than an insertion density of the specific pilot channel included in the unicast frame.12-09-2010
20110129046DISCRETE DENOISING USING BLENDED COUNTS - Various embodiments of the present invention relate to a discrete denoiser that replaces symbols in a received, noisy signal with replacement symbols in order to produce a recovered signal less distorted with respect to an originally transmitted, clean signal than the received, noisy signal. Certain, initially developed discrete denoisers employ an analysis of the number of occurrences of metasymbols within the received, noisy signal in order to select symbols for replacement, and to select the replacement symbols for the symbols that are replaced. Denoisers that represent examples of the present invention use blended counts that are combinations of the occurrences of metasymbol families within a noisy signal to determine the symbols to be replaced and the replacement symbols corresponding to them.06-02-2011
20110243283CHANNEL QUALITY ESTIMATION FOR MLSE RECEIVER - A receive signal processor jointly detects a signal-of-interest with one or more other signals. The signal-to-interference-plus-noise ratio for the signal-of-interest is determined by computing per-subcarrier signal-to-interference-plus-noise ratios for a plurality of subcarriers carrying the signal-of-interest, computing per-subcarrier capacities for the subcarriers based on the per subcarrier signal to interference ratios, and computing a total signal-to-interference-plus-noise ratio for the subcarriers based on the per-subcarrier capacities of the subcarriers.10-06-2011
20090067557Accurate Channel Quality Indicator for Link Adaptation of MIMO Communication Systems - A method for performing link adaptation in a Multiple Input Multiple Output (MIMO) system comprises: receiving a signal at a receiving unit of the MIMO system, calculating channel state information (CSI) from the received signal, and calculating a plurality of values of a parameter from the CSI, the parameter mapping to an error rate of the system, the mapping being substantially one-to-one within a range of interest of the error rate, each one of the calculated values corresponding to one of a plurality of Modulation Coding Schemes (MCSs).03-12-2009
20110044411METHODS AND APPARATUSES FOR REDUCING INTER-CARRIER INTERFERENCE IN AN OFDM SYSTEM - An OFDM telecommunications system includes a transmitter and a receiver. The receiver includes a canceller configured to reduce inter-carrier interference (ICI) in an OFDM symbol in the frequency domain.02-24-2011
20110019784RECEPTION APPARATUS, RECEPTION METHOD, PROGRAM, AND RECEPTION SYSTEM - Disclosed herein is a reception apparatus including: an acquisition section configured to acquire an orthogonal frequency division multiplexing signal composed resultingly of signals transmitted by the orthogonal frequency division multiplexing method from a plurality of transmission apparatuses; a correction value calculation block configured to calculate a correction value for correcting a drift amount of the orthogonal frequency division multiplexing signal using the phase of either a first pilot signal or a second pilot signal extracted from the acquired orthogonal frequency division multiplexing signal, the first pilot signal being obtained from pilot signals which are in phase with one another coming from the plurality of transmission apparatuses, the second pilot signal being acquired from pilot signals which are out of phase with one another coming from the plurality of transmission apparatuses; and a correction block configured to correct the drift amount of the orthogonal frequency division multiplexing signal in accordance with the calculated correction value.01-27-2011
20110026653CHANNEL ESTIMATION FOR WIRELESS COMMUNICATION - Techniques for deriving channel estimates with different channel estimation filters are described. In one scheme, a filter selection metric is determined for a signal to be recovered, a channel estimation filter is selected based on the filter selection metric, and a channel estimate is derived with the selected channel estimation filter. In another scheme, a first channel estimate is derived with a first channel estimation filter having a first filter response, a first signal is recovered with the first channel estimate, and interference due to the first signal is estimated and removed. A second channel estimate is derived with a second channel estimation filter having a second filter response that is different from the first filter response.02-03-2011
20110026652METHOD AND SYSTEM FOR DIVERSITY AND MASK MATCHING IN CHANNEL ESTIMATION IN OFDM COMMUNICATION NETWORKS USING CIRCULAR CONVOLUTION - A mobile device in an OFDM system receives an OFDM signal comprising RS tones and data OFDM symbols. The received RS tones are extracted for channel estimation using a masking operation. Masking parameters are determined by matching channel time variance using corresponding time domain samples of the extracted RS tones. As approximated channel impulse responses of transmission channels, the time samples are masked to perform the channel estimation. The channel time variance comprising inter-carrier interference and delay spread are measured, respectively. A mean of differences in power between neighbor adjacent subcarriers of the extracted RS tones is used for the inter-carrier interference measurement. The delay spread measurement such as root-mean-squared (RMS) delay spread is calculated using the approximated channel impulse responses. Masking parameters are determined based on the inter-carrier measurement and the RMS-DS measurement for generating channel estimates by masking the approximated channel impulse responses.02-03-2011
20090034665Method, System and Apparatus for Quantifying the Contribution of Inter-Symbol Interference Jitter on Timing Skew Budget - An apparatus, method and system are provided for quantifying communication channel intersymbol interference jitter effect contribution to timing skew. In general, lossy and lossless characteristics of the communication channel are preferably obtained and an output signal of the communication channel is sampled. From the sampled output signal and the lossy characteristics of the communication channel, an input signal may be derived. Using the lossless characteristics of the communication channel, the derived input signal and the sampled output signal, a value indicating the contribution of intersymbol interference jitter effect on timing skew budget for a selection communication channel may be obtained.02-05-2009
20100329400ESTIMATING METHOD FOR MAXIMUM CHANNEL DELAY AND CYCLIC PREFIX (CP) AVERAGING METHOD IN OFDM RECEIVER - An estimating method for maximum channel delay and cyclic prefix (CP) averaging method in orthogonal frequency division multiplexing (OFDM) receiver are described. Specifically, the estimating method performs the estimation of the maximum channel delay by adding the CP and the main OFDM signal for increasing the signal-to-noise ratio (SNR) and for reducing the inter-carrier interference (ICI). The CP averaging method is used to acquire a portion of the CP by using the maximum channel delay so as to increase the performance of the OFDM receiver.12-30-2010
20110080983METHOD FOR SUPPRESSION OF OFDM ENERGY SPECTRAL DENSITY FOR MINIMIZATION OF OUT OF BAND EMISSION OR UTILIZATION OF FRACTURED SPECTRUM - The Energy spectral density of OFDM signals inherently rolls off slowly. Slow OFDM spectral rolloff has system level implications traditionally mitigated by some combination of the following: addition of bandlimiting filtering; use of significant guard bands of zeroed tones; and, guard time shaping. Each of these techniques negatively impact system performance and/or flexibility. This application presents a methodology for active cancellation of out of band spectral energy. The technique can be used by itself or in conjunction with above traditional methods to help control out of band emission. Examples of the use of the new technique are provided. Computational cost of the new technique is also discussed.04-07-2011
20090323871Application of Superfast Algorithms to a Pilot-Based Channel Estimation Process - An apparatus and method of applying a superfast algorithm to a pilot-based channel estimation process includes receiving a signal comprising information bits transmitted in a wireless channel, executing the pilot-based channel estimation process having p structures for a vector of pilot structures and an upper bound N for a channel spread, determining a result of a matrix inversion of a channel correlation matrix for an error channel estimation offline without performing a matrix inversion, storing pilot information of the received signal for channel recovery in a transform domain, representing the Toeplitz inverse by a FFT representation, detecting and estimating nonzero taps of a channel impulse response of the wireless channel, obtaining a non-structured minimum mean-square-error (MMSE) estimate as a first estimate of locations of the nonzero taps, and replacing the non-structured MMSE estimate by an estimate computed by a tap detection algorithm.12-31-2009
20110080982SIGNAL QUALITY ESTIMATION FROM COUPLING MATRIX - The quality of a received signal in a non-linear receiver is estimated using a coupling matrix G or Q that describes the interaction of symbols in the received signal with other symbols and/or how the impairment (noise and interference) interacts in the received signal. The coupling matrix is also useful for joint detection. The signal quality estimate may include, e.g., the minimum eigenvalue, and other functions, such as the determinant and trace of the coupling matrix. When G or Q varies with each block, as in CDMA systems employing longcode scrambling, a representative matrix can be used, such as a matrix of RMS values or average magnitudes of real and imaginary components. The signal quality estimate can be expressed as a bit error rate (BER).04-07-2011
20110085626RECEIVE UNIT FOR RECEPTION OF MULTIPLE SATELLITE SIGNALS - A satellite receive unit for receiving a plurality of satellite signals from a plurality of satellites, the satellite receive unit including: a plurality of low noise blocks each for receiving one or more of the satellite signals and providing a received signal, at least one of the low noise blocks receiving a plurality of the satellite signals; and a satellite signal processing unit including a plurality of branches each arranged to receive a corresponding one of the received signals from the plurality of low noise blocks, each branch having a multiplier arranged to weight the received signal by multiplying by a corresponding coefficient; and an adder arranged to add the weighted signals of each branch to generate an output satellite signal.04-14-2011
20090323870Identification Circuit with Repeatable Output Code - A comparator receives a first read of voltage differentials from a series of bit cells, compares the first read to a positive voltage offset of a given magnitude, and set bits in a first bit stream to values that are dependent upon whether the voltage differential from a given bit cell is greater than the positive voltage offset. The first bit stream is then stored in a first register. The comparator also receives a second read of the voltage differentials from the series of bit cells, compares the second read to a negative voltage offset of the given magnitude, and sets bits in a second bit stream to values that are dependent upon whether the voltage differential from a given bit cell is greater than the positive voltage offset. The second bit stream is stored in a second register. The comparator then compares the first bit stream to the second bit stream, and set bits in a mask string dependent upon whether the bits in a given position of the first bit stream and the second bit stream are identical. A third register receives the mask string. The comparator additionally receives a subsequent read of the voltage differentials from the series of bit cells, compares the subsequent read to a zero voltage offset, and set bits in a subsequent bit stream to values that are dependent upon whether the voltage differential from a given bit cell is greater than the zero voltage offset. The subsequent bit stream is compared to the mask string, and bits of the subsequent bit stream that are disposed in positions set in the mask string are corrected.12-31-2009
20100150285Method And System For A Combined Signal Detection For Physical Layer Communication Devices - Communication devices coupled via a communication link may comprise physical layer devices that may be operable to determine presence of a received signal and to mitigate noise in the signal prior to processing and/or validating the signal. Analog and/or digital signal processing may be utilized to process the signal and/or mitigate noise in the signal. Noise mitigation may comprise near-end crosstalk cancelling and/or echo cancelling and/or may utilize local transmit signal information. Subsequent to noise mitigation, samples of the noise reduced signal may be accumulated and/or an average signal strength and/or average signal power level may be determined. The average signal strength and/or average signal power level may be compared to one or more thresholds which may be configurable and/or programmable.06-17-2010
20120243647SYNCHRONOUS DETECTION METHOD AND DEVICE - In a synchronous detection of an OFDM signal as an input signal composed of carrier waves, a clock generation part generates clock signals CK09-27-2012
20100067629PERFORMANCE IN A TIME-FREQUENCY INTERLEAVED ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM - In one embodiment, a TFI-OFDM receiver system (03-18-2010
20100061495APPARATUS FOR PERFORMING CHANNEL ESTIMATION IN A RECEIVING DEVICE - An apparatus for performing channel estimation includes a time-domain estimating circuit to perform a channel estimation on a time-domain received signal to output a time-domain estimated signal, a second frequency-domain converting circuit to convert the time-domain estimated signal into a frequency-domain estimated signal, an error computing circuit to produce an error signal based on the frequency-domain estimated signal and a frequency-domain received signal, and a compensation circuit to compensate the frequency-domain estimated signal using the error signal so as to produce a final channel estimation signal. The apparatus is located in a receiving device that includes a first frequency-domain converting circuit to convert the time-domain received signal into the frequency-domain received signal, and an equalizer to generate a frequency-domain recovered signal based on the frequency-domain received signal and the final channel estimation signal.03-11-2010
20100061496INTERFERENCE CANCELLATION FOR WIRELESS COMMUNICATIONS - Techniques for improving the capacity of a wireless communications system using interference cancellation (IC). In an early decoding and IC aspect, a frame transmitted from a user to a base station may be decoded prior to the entire frame being received by the base station. The remaining portion of the frame may then be re-constructed at the base station prior to its reception, and cancelled from the receive signal to reduce the interference to frames received from other users. In a power control aspect for early decoding and IC, the power control target level at a local base station may be adjusted in response to successfully early decoding a frame, without affecting the overall outer loop power control operation. Further aspects include late decoding techniques for utilizing the IC of other users' signals to improve the probability of decoding a given user's frames, as well as techniques for traffic channel demodulation using channel re-estimation.03-11-2010
20090028278METHOD AND DEVICE FOR REDUCING SURROUNDING COUPLING NOISE - A method and device for reducing a surrounding coupling noise are disclosed. The method and device include receiving a signal from a receiving end of a line to be processed and obtaining a reference noise signal; determining a weight coefficient for adjusting the reference noise signal; and filtering the reference noise signal with a transfer function configured by the determined weight coefficient, superposing the filtered signal with the signal received by the receiving end of the line to be processed, and outputting the superposed signal.01-29-2009
20090028277Method and system for denoising noisy signals - Embodiments of the present invention are directed to generally applicable denoising methods and systems for recovering, from a noise-corrupted signal, a cleaned signal equal to, or close to, the original, clean signal that suffered corruption due to one or more noise-inducing processes, devices, or media In a first pass, method embodiments and system embodiments of the present invention receive an instance of one of many different types of neighborhood rules and use the received neighborhood rule to acquire statistics from a noisy signal. In a second pass, the method embodiments and system embodiments of the present invention receive an instance of one of many different types of denoising rules, and use the received denoising rule to denoise a received, noisy signal in order to produce a cleaned signal.01-29-2009
20110069794METHOD AND SYSTEM FOR INTERFERENCE CANCELLATION - Aspects of a method and system for interference cancellation substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims. In this regard, a receiver may be operable to receive a differential signal via a differential channel, and to sense a common mode signal on the differential channel. A frequency range in which interference is present in the common mode signal may be determined. The differential signal and the common mode signal may be filtered to attenuate frequencies outside the determined frequency range. A phase and/or amplitude of the filtered common mode signal may be adjusted based on the filtered differential signal and the adjusted and filtered common mode signal may be subtracted from the received differential signal. The common mode signal may be sensed via a pair of resistors coupled to the differential channel.03-24-2011
20100098198RECOVERY OF DATA FROM A MULTI CARRIER SIGNAL - In an embodiment, a multi-carrier signal (e.g., an OFDM signal) is received over a channel. Indicators of interference and the channel response at a carrier frequency of the signal are determined, and compared. If the indicator of interference has a particular relationship to the indicator of the channel response, then a data value transmitted at the carrier frequency is recovered from a data value received at the carrier frequency according to a particular data-recovery algorithm. Because the particular data-recovery algorithm may be faster than a conventional data-recovery algorithm, recovering one or more data values with the particular algorithm may increase the speed at which data is recovered from a multicarrier signal as compared to using a conventional data-recovery algorithm.04-22-2010
20100098197METHOD AND APPARATUS FOR DETECTION AND CANCELLATION OF SINGLE-TONE OR MULTI-TONE INTERFERENCE IN COMMUNICATION SYSTEMS - A method and system for canceling an interference signal are provided. In the method, a received signal is transformed from a time domain to a frequency domain at relative low precision to obtain an estimated frequency and an estimated amplitude of the interference signal. A reference signal is generated using the estimated frequency and the estimated amplitude. An error signal is generated using the received signal and the reference signal based on minimum correlation criteria. The reference signal is adjusted using the error signal based on an adaptive algorithm. The reference signal is subtracted from the received signal to obtain the useful signal.04-22-2010
20100002813Soft Scaling Method and Apparatus - A received signal of interest is processed by determining timing of interference spikes in the received signal of interest. Receivers can determine when certain types of interference spikes are expected to occur, e.g., based on when different users are scheduled to transmit data during an overlapping portion of the same transmission time interval. The interference timing information is used by the receiver to soft scale signal values recovered from the received signal of interest that coincide with the interference spikes separately from remaining ones of the signal values. This way, fast changing interference power can be accurately tracked during periods of known interference spikes while also accurately tracking slower changing interference power during other periods.01-07-2010
20090285343SYSTEM AND METHOD FOR CANCELING INTERFERENCE IN A COMMUNICATION SYSTEM - A filter settings generation operation includes sampling a communication channel to produce a sampled signal. The sampled signal is spectrally characterized across a frequency band of interest to produce a spectral characterization of the sampled signal. This spectral characterization may not include a signal of interest. The spectral characterization is then modified to produce a modified spectral characterization. Filter settings are then generated based upon the modified spectral characterization. Finally, the communication channel is filtered using the filter settings when the signal of interest is present on the communication channel. In modifying the spectral characterization, pluralities of spectral characteristics of the spectral characterization are independently modified to produce the modified spectral characterization. Modifications to the spectral characterization may be performed in the frequency domain and/or the time domain. One particular spectral modification that is performed is raising of the noise floor of the spectral characterization to meet a budgeted signal-to-noise ratio. Other spectral modifications include modifying spectral components corresponding to an expected interfering signal. In modifying these spectral characterizations, spectral components corresponding to a plurality of expected interfering signals may be modified.11-19-2009
20090022253INPUT CIRCUIT AND SEMICONDUCTOR INTEGRATED CIRCUIT COMPRISING THE INPUT CIRCUIT - Provided are a channel estimation device and an equalization device capable of achieving high channel estimation accuracy with less amount of calculation processing. The equalization device includes: a channel estimation section including a ZF calculation/clipping processing section and correlation processing section; a weight calculation section; and an equalization filter. The ZF calculation/clipping processing section uses a signal obtained by converting a pilot code into a frequency domain to calculate a pilot reference signal according to a Zero Forcing (ZF) method and clips the gain of the calculated pilot reference signal to a predetermined value to generate a clipped pilot reference signal. The correlation processing section performs correlation between a pilot reception signal in the frequency domain and clipped pilot reference signal to estimate channel characteristics of the frequency domain. The weight calculation section calculates an equalization weight based on the channel characteristics of the frequency domain. The equalization filter performs equalization processing of a frequency domain reception signal using the equalization weight.01-22-2009
20100220823Systems and Methods for Mitigating Self-Induced Far-End Crosstalk - Systems and methods for partial self-FEXT (far-end crosstalk) are described. One method, among others, comprises determining one or more instantaneous characteristics of an input signal, wherein the one or more instantaneous characteristics comprise one or more of amplitude of the input signal and an energy level of the input signal. The method further comprises selecting one or more disturbers to cancel according to the one or more instantaneous characteristics, wherein selecting one or more disturbers is performed on a per-DMT (discrete multi-tone) symbol basis.09-02-2010
20080310563BROADCAST CHANNEL ESTIMATOR - A communication system comprises a receiver, which may generate broadcast coefficients that represent the characteristics of a channel using the channel information encoded in the segment synchronization units. The receiver may also use the channel information encoded in both the segment synchronization units and the field synchronization units to accurately determine the characteristics of a long channel.12-18-2008
20090086860RECEIVER APPARATUS - A receiving apparatus includes a digital signal demodulating unit, including a desired-signal transmission-path estimating unit that performs transmission path response matrix estimation for a desired signal; an interface-signal transmission-path estimating unit that performs transmission path response matrix estimation for an interference signal; a combined-transmission-path matrix generating unit that combines the matrices to generate a combined transmission path response matrix; a matrix calculating unit that converts the combined matrix into an upper triangular matrix; a hypersphere generating unit that generates a hypersphere centering on a reception signal point in a lattice point space; and a symbol searching unit that forms the lattice point space from the combined matrix by searching lattice points in the hypersphere for a lattice point having the smallest metric to the reception signal point, to determine the lattice point as estimate values of the desired signal and interference signal.04-02-2009
20080212726Method and Apparatus for Signal Processing and Encoding and Decoding Method, and Apparatus Therefor - An apparatus for processing a signal and method thereof are disclosed. Data coding and entropy coding are performed with interconnection, and grouping is used to enhance coding efficiency. The present invention includes the steps of obtaining difference information and entropy-decoding the difference information according to an entropy coding scheme including time grouping and frequency grouping and data-decoding the difference information according to a data decoding scheme including a pilot difference, a time difference and a frequency difference.09-04-2008
20080292033Arrangements for acquiring and using data obtained from received interference to facilitate data recovery - In some embodiments a method is disclosed for detecting periodic interference and predicting future interference times. The method can include detecting an arrival time of a first occurrence of interference and detecting an arrival time of a second occurrence of interference. The method can include transmitting preemptive interference mitigation control signals that anticipate future arrival times of interference. A system is disclosed that includes a periodicity detector, an interference profiler and a mitigation control module. The system can provide interference mitigation features to a data recovery system. Other embodiments are disclosed.11-27-2008
20080267327Nonlinear echo compensator for class B transmitter line driver - A nonlinear echo compensator comprises a mapping circuit that includes a weighting circuit that generates a weighted signal based on a current symbol and a prior symbol and a function generating circuit that selects one of N functions based on the weighted signal, where N is an integer greater than one. The mapping circuit generates a driving signal based on the selected one of the N functions and the weighted signal. A canceling circuit generates a nonlinear echo compensation signal based on the driving signal.10-30-2008
20110211662ANTENNA GROUPING AND GROUP-BASED ENHANCEMENTS FOR MIMO SYSTEMS - Embodiments of the present disclosure provide a transmitter, a receiver and methods of operating a transmitter and a receiver. In one embodiment, the transmitter has at least three transmit antennas and includes a feedback decoding portion configured to recover at least one group-based channel quality indicator provided by a feedback signal from a receiver, wherein each group-based channel quality indicator corresponds to one of a set of transmission layer groupings. The transmitter also includes a modulator portion configured to generate at least one symbol stream and a mapping portion configured to multiplex each symbol stream to at least one transmission layer grouping. The transmitter further includes a pre-coder portion configured to couple the transmission layers to the transmit antennas for a transmission. The receiver includes a decoder portion which is configured to use decoded signals from at least one group to decode the other groups.09-01-2011
20080253488INTERFACE SYSTEM AND FLAT PANEL DISPLAY USING THE SAME - An interface system capable of reducing or minimizing an electromagnetic interference. The interface system includes a serializing unit for receiving first data having a plurality of bits and second data having a plurality of bits, and for serially outputting the plurality of bits of the received first data and second data as 2 bits; a transmission circuit for generating 4 voltage levels in accordance with the 2 bits supplied from the serializing unit; a receiving circuit for recovering the 2 bits using the voltage levels supplied from the transmission circuit; and a deserializing unit for recovering the first data and the second data while sequentially storing the 2 bits supplied from the receiving circuit.10-16-2008
20080253487ADAPTIVE 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
20110164709APPARATUS AND METHOD FOR ESTIMATING CHANNEL IN BROADBAND WIRELESS COMMUNICATION SYSTEM - An apparatus and method for channel estimation decrease overhead and hardware complexity while supporting both Wiener-type channel estimation and Finite Impulse Response (FIR) filtering/Infinite Impulse Response (IIR) filtering in a wireless communication system. The apparatus includes a storage unit for storing coefficient sets for a plurality of channel estimation types. A controller selects one of the plurality of channel estimation types according to at least one of a type of a pilot signal and a reliability value of a channel parameter. An N-tap filter, including N multipliers and (N−1) adders, determines channel estimation values of data tones by using the coefficient sets for the selected channel estimation type.07-07-2011
20100284500ESTIMATING SIGNAL TO INTERFERENCE RATIO IN A WIRELESS COMMUNICATIONS RECEIVER - A method and corresponding system for generating an estimate of at least one of a signal power, a noise power and a signal to interference ratio for signal samples received via first and second wireless channels, the signal samples corresponding to pilot symbols transmitted in respective different structures via the first and second wireless channels. The method comprises: calculating first and second variables, each variable being a sequence of values computed from the received signal samples and the pilot symbols for each respective first and second wireless channel; generating first and second channel estimates from the first and second variables; combining the first and second channel estimates to generate a combined channel estimate; and generating at least one of the signal power, noise power and SIR using the combined channel estimate.11-11-2010
20100329402Advanced Signal Processors for Interference Cancellation in Baseband Receivers - A multi-mode receiver includes a channel decomposition module (e.g., a Rake receiver) for separating a received signal into multipath components, an interference selector for selecting interfering paths and subchannels, a synthesizer for synthesizing interference signals from selected sub channel symbol estimates, and an interference canceller for cancelling selected interference in the received signal. At least one of the channel decomposition module, the synthesizer, and the interference canceller are configurable for processing multi-mode signals.12-30-2010
20100329399Method and Apparatus for Interference Post-Compensation Using a Bandwidth-Adaptive Postcoder Interface - In a communication system, a postcoder is coupled between first and second portions of each of a plurality of receivers. The postcoder is configured to receive an adaptive index representation of a scaled signal associated with the first portion of a first one of the receivers, and to process the adaptive index representation using an adjusted postcoder coefficient to generate a postcompensation signal. The postcompensation signal is supplied by the postcoder to the second portion of a second one of the receivers for use in postcompensation of at least one signal received by the second receiver.12-30-2010
20100329401SYSTEM AND METHOD FOR CONTROLLING COMBINED RADIO SIGNALS - A method for controlling a combined waveform, representing a combination of at least two signals having orthogonal frequency multiplexed signal components, comprising: receiving information defining the at least two signals; transforming the information defining each signal to a representation having orthogonal frequency multiplexed signal components, such that at least one signal has at least two alternate representations of the same information, and combining the transformed information using the at least two alternate representations, in at least two different ways, to define respectively different combinations; analyzing the respectively different combinations with respect to at least one criterion; and outputting a respective combined waveform or information defining the waveform, representing a selected combination of the transformed information from each of the at least two signals selected based on the analysis.12-30-2010
20100329398Receiver and method for performing interference cancellation - To address the need for new interference cancellation techniques that are able to deliver adequate performance but with reduced processing requirements, various embodiments are described. In some embodiments, a receiving device demodulates and decodes (12-30-2010
20110116583SYSTEM AND METHOD FOR ENCODING AND DECODING INFORMATION SIGNALS USING A PRIORI INFORMATION - A system and method for coding and decoding an information signal sent through a communication system. The system includes: an encoder for encoding the information signal without adding additional information and for sending an encoded information signal; and a soft bit decoder including a-priori information related to the communication system for receiving the encoded information signal and decoding the encoded information signal using the a-priori information.05-19-2011
20110135044System and Method for Canceling Interference in a Communication System - A filter settings generation operation includes sampling a communication channel to produce a sampled signal. The sampled signal is spectrally characterized across a frequency band of interest to produce a spectral characterization of the sampled signal. This spectral characterization may not include a signal of interest. The spectral characterization is then modified to produce a modified spectral characterization. Filter settings are then generated based upon the modified spectral characterization. Finally, the communication channel is filtered using the filter settings when the signal of interest is present on the communication channel. In modifying the spectral characterization, pluralities of spectral characteristics of the spectral characterization are independently modified to produce the modified spectral characterization. Modifications to the spectral characterization may be performed in the frequency domain and/or the time domain. One particular spectral modification that is performed is raising of the noise floor of the spectral characterization to meet a budgeted signal-to-noise ratio. Other spectral modifications include modifying spectral components corresponding to an expected interfering signal. In modifying these spectral characterizations, spectral components corresponding to a plurality of expected interfering signals may be modified.06-09-2011
20100183105OFDM RECEIVER - An OFDM receiver (07-22-2010
20100202575Interference cancellation with a time-sliced architecture - Example embodiments include methods of interference cancellation at NodeB receivers of baseband antenna signals including physical channels. The methods include canceling interference from a received baseband antenna signal by removing a reconstructed baseband signal from the processed received baseband antenna signal. The processed reconstructed baseband signal includes users whose physical data channel signals were successfully decoded. Methods also include removing interference from a received baseband signal to form an interference cancelled baseband signal that will be processed by the receiver. The interference cancelled baseband signal is the received baseband antenna signal minus users' signal interference contributions whose demodulated physical data channel signals have a determined user symbol energy value that exceeds a threshold. Methods further include removing interference from a user's signal to be error corrected. The interference is symbol interference from an earlier successfully decoded user's symbols. The user symbol interference is determined by cross correlations.08-12-2010
20110135043System for and method of removing unwanted inband signals from a received communication signal - A system for and method of removing one or more unwanted inband signals from a received communications signal is described. The inband signal or signals may comprise noise, interference signals, or any other unwanted signals that impact the quality of the underlying communications. A receiver receives a communication signal, the received communication signal including the desired communication signal and one or more inband signals. A signal processor processes the received signal to form an estimate of the desired communication signal and an estimate of the inband signals. The estimate of the inband signals is thereby removed from the received signal. The estimate of the desired communication signal and the estimate of the inband signals are formed without prior knowledge of characteristics of the inband signals and without obtaining a copy of any of the inband signals from any source other than the received signal.06-09-2011
20100111237INTERFERENCE CANCELLATION SYSTEM AND METHOD - An interference cancellation system and method for a communication system comprising a data bus carrying primary signals having an A component and a non-A component are provided. The interference cancellation system has an input port, an A data extraction block and an interference cancellation circuit. The input port receives a sampled primary signal from the data bus, via an analog-front end block having sampling means. The A data extraction block extracts A data from the sampled primary signal and outputs A decoded data. The interference cancellation circuit has an interference measurement block and a cancellation block. The interference measurement block receives the A decoded data and the sampled primary signal and produces an A interference signal. The cancellation block receives the sampled primary signal and the A interference signal and subtracts the A interference signal from the sampled primary signal, producing an output signal with the A component substantially attenuated.05-06-2010
20100111238ERROR SIGNAL PROCESSING SYSTEMS FOR GENERATING A DIGITAL ERROR SIGNAL FROM AN ANALOG ERROR SIGNAL - Apparatus, systems, and methods are provided for controlling the output of a transmitter using a digital error signal. A method comprises generating a digital reference signal based on a baseband input signal and converting the digital reference signal to an analog reference signal. The method further comprises generating an analog error signal in response to a difference between the analog reference signal and an analog output signal. The method further comprises generating a digital error signal from the analog error signal, and generating an input signal for the transmitter based on the baseband input signal and the digital error signal.05-06-2010
20110096876METHOD AND DEVICE FOR DETECTING A PHASE ERROR OF A SIGNAL - A method for receiving a signal having a succession of symbols, transmitted by a digital modulation, each symbol transmitted having a phase and an amplitude belonging to a set of values in finite number, the method includes evaluating a phase error (PHE) on a received symbol (S), resulting from a signal transmission noise, correcting the phase of the received symbol according to the phase error evaluated, demodulating the symbol corrected in phase, and modeling the transmission noise by a Gaussian component not correlated with the signal received and defined by a power and an interference component defined by an amplitude and which phase is substantially uniformly distributed, the phase error of the received symbol evaluated on the basis of the power of Gaussian component and the amplitude of the interference component.04-28-2011
20100166125SYSTEMS AND METHODS FOR ENHANCING PERFORMANCE OF A LOW-POWER TRANSCEIVER - According to some embodiments, a digital switching distortion canceller may receive Ethernet data along with an Ethernet class AB transceiver switching signal. A combiner may combine the output of the digital switching distortion canceller with a digital high switching distortion signal to generate a corrected output signal. According to other embodiments, a switching-signal-to-voltage-converter receives an Ethernet class AB transceiver switching signal and generates a common-mode compensation voltage adjustment. An analog combiner may combine the common-mode compensation voltage adjustment with a noisy common-mode signal to generate a stabilized common-mode voltage. Note that reduction of switching-related distortion might be achieved in the digital domain, in the analog domain, or in both domains according to the embodiments described herein.07-01-2010
20100158173CHANNEL ESTIMATING METHOD IN WIRELESS COMMUNICATION SYSTEM AND APPARATUS THEREOF - Provided is a method and system for estimating a channel in a wireless communication system. An interference coefficient is calculated based on a known structure of a pilot, and a channel value in a frequency domain is estimated. A channel value in a time domain is obtained by transforming the channel value in the frequency domain and the channel delay values are subtracted from the channel value in the time domain, thereby cancelling interference.06-24-2010
20110051864MULTI-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
20110188617DEVICE AND METHOD FOR BLOCKING-SIGNAL REDUCTION - A processing device (08-04-2011
20090175392System, Apparatus, and Method for Cancelling Interferences of Received Signals - An apparatus and a method for cancelling an interference of each of a plurality of received signals are provided. The apparatus comprises an estimation module, an ordering module, a selection module, an equalizer, and a cancellation module. The estimation module estimates a plurality of estimated channels according to a first predetermined number of pilot-tones. The ordering module decides a decision order for processing. The selection module selects a second predetermined number of the received signals as the second predetermined number of processing signals. The equalizer estimates the estimated values, wherein each of the estimated values corresponds to a processing signal. The decision module decides a decided value for each of the estimated values. The cancellation module cancels the interference for each of the processing signals according to the corresponding decided value and the corresponding channel. Then, the estimation module further estimates the estimated channels according to the pilot-tones and a plurality of estimated values.07-09-2009
20100027727Recovering symbols in a communication receiver - Methods of recovering symbols and corresponding communication receivers including dual receivers configured to perform the method, where the method comprises: sampling a received signal that includes interference to provide received samples; determining a plurality of high power symbols and determining alternate symbols for a portion of the plurality of high power symbols based on the received samples and based on known training symbols; and deriving a sequence of recovered symbols corresponding to the received samples based on the received samples and augmented training symbols, the augmented training symbols comprising the known training symbols augmented by the plurality of high power symbols with one or more alternate symbols replacing a corresponding one or more high power symbols.02-04-2010
20100027726MULTI-CARRIER RECEIVER WITH DYNAMIC POWER ADJUSTMENT AND METHOD FOR DYNAMICALLY ADJUSTING THE POWER CONSUMPTION OF A MULTI-CARRIER RECEIVER - A method for dynamically adjusting the power consumption of a multi-carrier receiver and a multi-carrier receiver with dynamically power adjustment. The method includes receiving a multi-carrier signal, wherein the multi-carrier signal comprises a plurality of sub-carriers. Channel characteristics of each sub-carrier are estimated according to the demodulated multi-carrier signal. ICI strength is estimated from the demodulated multi-carrier signal. A system performance is detected. The estimated ICI is subtracted when the ICI strength exceeds an ICI threshold and the system performance is less than a system performance threshold. The demodulated multi-carrier signal is then equalized is based on the estimated channel characteristics, and the system performance is updated according to the equalized multi-carrier signal.02-04-2010
20110216858METHOD AND DEVICE FOR CORRECTING IQ IMBALANCE OF BASEBAND SIGNALS IN WIRELESS COMMUNICATION RECEIVER - A method and a device for correcting In-phase/Quadrature (IQ) imbalance in baseband signals of a wireless communication receiver are disclosed. The method includes the following: the receiver receives Radio Frequency (RF) signals, and processes the signals to generate In-phase (I) signals and Quadrature (Q) signals; the receiver calculates to obtain an autocorrelation value E(|I|09-08-2011
20100272221PEAK-TO-AVERAGE POWER REDUCTION METHOD - A method of reducing peak-to-average power in a hybrid signal is provided. The method determines peaks in power by defining a sample point by way of a digital vector and an analog vector. The digital and analog vectors are added together to generate a hybrid vector which is used to compare the sample point to the maximum desired peak threshold. An error vector is used to correct the sample point to a desired power level. Once the sample point has been corrected it can be added back to the analog signal and transmitted.10-28-2010
20090086862DIGITAL CROSS-POLAR INTERFERENCE CANCELLATION - Cross-polar interference cancellation in a dual-polarization system is described. A terminal in a satellite communication system may receive a first communication signal in a first polarization and a second communication signal in a second polarization substantially orthogonal to the first polarization. The terminal may correlate in-phase or quadrature components of the first communication signal with in-phase or quadrature components of the second communication signal to generate one or more correlation measurements. Correction terms may be generated, using the correlation measurements, to remove at least some of the cross-polar interference.04-02-2009
20090092208Decoding of forward error correction codes in the presence of phase noise - A communication receiver includes a front end, which is arranged to receive a Radio Frequency (RF) signal, which includes modulated symbols carrying data that have been encoded by a block Forward Error Correction (FEC) code. The front end converts the RF signal to a sequence of soft received symbols, wherein the soft received symbols are subject to distortion by at least first and second noise components having respective at least first and second statistical distributions. A metric calculation unit is arranged to process the soft received symbols so as to extract parameters indicative of the at least first and second statistical distributions, and to compute FEC metrics based on the extracted parameters. A FEC decoder is arranged to accept the FEC metrics as input, and to process the metrics in an iterative FEC decoding process so as to decode the FEC code and reconstruct the data.04-09-2009
20110069795Method and System For Decoding Single Antenna Interference Cancellation (SAIC) and Redundancy Processing Adaptation Using Frame Process - Aspects of a method and system for decoding single antenna interference cancellation (SAIC) and redundancy processing adaptation using frame process are provided. A receiver may decode video, voice, and/or speech bit sequences based on a first decoding algorithm that may utilize data redundancy and that may impose physical constraints. The receiver may also decode a bit sequence based on a second decoding algorithm that utilizes SAIC. The first and second decoding algorithms may be adapted to perform in parallel and a decoded received bit sequence may be selected based on a redundancy verification parameter. The first and second decoding algorithms may also be adapted to be performed sequentially where the subsequent decoding operation may be conditioned to the initial decoding operation. Moreover, either the first or the second decoding algorithm may be selected for decoding the received bit sequence. The selection may be based on noise and/or interference measurements.03-24-2011
20110085627INTERFERENCE REJECTION COMBINING FOR MULTI-USER MIMO TELECOMMUNICATIONS SYSTEM - Method and apparatus are provided for processing a received signal for making a symbol estimate of a symbol included in a signal transmitted in a Multiple-Input-Multiple-Output (MIMO) system. In an example mode, the method comprises (1) providing at least a sub-set of precoding matrices which are candidates for use in transmission of an interfering signal in a MIMO system; (2) using the received signal and plural candidates of the subset to determine corresponding plural covariance matrices, each of the plural covariance matrices being formed using a corresponding candidate precoding matrix; (3) determining which of the candidates is a trace minimizing candidate which is associated with one of the plural covariance matrices that has a minimum trace value; (4) forming a weighting matrix using the trace minimizing candidate; and (5) using the weighting matrix to make the symbol estimation.04-14-2011
20100158169Dynamic RFI mitigation - Provided herein are different embodiments for performing radio frequency interference (RFI) mitigation in electronic devices such as mobile computing systems. In some embodiments, a dynamic RFI mitigation scheme allows for monitoring of wireless channels for RFI and to adaptively shift an identified RFI source (e.g., system clock) harmonics, e.g., either out of the on-channels or to a neutral position within the on-channels such as by using cost-function analysis.06-24-2010
20110110472METHOD, APPARATUS, AND SYSTEM FOR MICROWAVE SIGNAL CORRECTION - A method, an apparatus, and a system are provided in various embodiments of the present invention. According to embodiments of the present invention, the receiver samples the frequency signal from the transmitter to obtain sampling data and obtain the feedback IQ signal from the sampling data, and performs signal correction by using the feedback IQ signal. Sampling the received radio frequency signal does not need an additional component. The receiving channel installed in the receiver can be used to receive the radio frequency signal, which reduces the cost and power consumption.05-12-2011
20120099684Frequency Interference Detection And Correction - A system for detecting and correcting for spurious frequencies that may coincide in a bandwidth of interest in an RF metrology system. The system can (1) utilize a deterministic scheme to detect an interference by a spurious frequency and correct the distortion effect or (2) utilize a mixed signal processing architecture to avoid the occurrence of spurious frequency contamination. A detection scheme identifies the event of distortion and triggers either (a) a shift in the analog to digital convert sample rate or (b) a mathematical vector manipulation. The shift of the analog to digital convert sample rate moves an aliased image of the spurious frequency outside of the frequency of interest. The mathematical vector correction removes the distortion and restores the signal of interest.04-26-2012
20120002768DISTORTION-CORRECTING RECEIVER AND DISTORTION CORRECTION METHOD - Disclosed are a distortion-correcting receiver and a distortion correction method capable of precisely cancelling inter-modulation secondary distortion even when an input signal is markedly band-limited in a reception processing unit. In the distortion-correcting receiver (01-05-2012
20120002767FAST RESYNCHRONIZATION FOR RECEPTION IN TIME SLICING - A method and an apparatus for achieving fast resynchronization of received signals in a time slice in DVB-T/H systems. When the clock drift is low, the location of the symbol window can be decided based on a previous time slice. When the clock drift is high and when there are large delay spreads, the location of the symbol window can be decided based on the detected scattered pilot positions. The placement of the symbol window can further be enhanced through processing of the received TPS bits.01-05-2012
20120207255METHOD AND APPARATUS FOR REDUCING OR REMOVING CLICK NOISE - The invention relates to an apparatus and a method for detecting and correcting input signals regarding click noise, using a first detector unit and a second correction unit, the detector unit differentiates the input signal and extracts the noise signal and compares the sum of two noise samples with a threshold value and in case this sum exceeds the threshold value a click is observed, while the correction unit corrects the input signal in the phase domain and differentiates it prior to outputting the corrected signal.08-16-2012
20120207256INTERFERENCE CANCELLATION WITH A TIME-SLICED ARCHITECTURE - Example embodiments include methods of interference cancellation at NodeB receivers of baseband antenna signals including physical channels. The methods include canceling interference from a received baseband antenna signal by removing a reconstructed baseband signal from the processed received baseband antenna signal. The processed reconstructed baseband signal includes users whose physical data channel signals were successfully decoded. Methods also include removing interference from a received baseband signal to form an interference cancelled baseband signal that will be processed by the receiver. The interference cancelled baseband signal is the received baseband antenna signal minus users' signal interference contributions whose demodulated physical data channel signals have a determined user symbol energy value that exceeds a threshold. Methods further include removing interference from a user's signal to be error corrected. The interference is symbol interference from an earlier successfully decoded user's symbols. The user symbol interference is determined by cross correlations.08-16-2012
20120045026RECOVERING DISTORTED DIGITAL DATA - In one aspect, a method to recover digital data includes receiving a distorted digital data stream and processing the distorted digital data stream to remove distortions. The processing includes detecting state changes, removing noise and identifying valid pulses. The processing also includes forming an undistorted data stream based on the processing.02-23-2012
20100303181Scalable Satellite Receiver System - A receiver for a multi-channel communication system can include a down-converter device, an analog-to-digital converter (ADC), and a plurality of digital channel selection devices. The down-converter device can be configured to down-convert a plurality of analog signals from the multi-channel communication system to a plurality of corresponding low intermediate frequency (IF) signals. The ADC can be configured to convert the plurality of corresponding low-IF signals to a plurality of digital signals. Further, each digital channel selection device from the plurality of digital channel selection devices can be configured to select a digital signal corresponding to a channel of interest from the plurality of digital signals for further processing.12-02-2010
20110064173Multi-band single-carrier modulation - Multi-band single-carrier modulation. A novel approach is presented by which interference compensation may be performed for signals received by a piconet operable device. The piconet operable device may be implemented within a region that includes two or more SOPs (Simultaneously Operating Piconets). Estimation of the level and location of interference is performed and the input to a decoder (within the piconet operable device) is selectively weighted to ensure that the effect of any existent interference within the signal received by the piconet operable device is minimized. Different interference levels are dealt with differently. For one example, portions of the received signal having undergone a large amount of interference may be simply treated as erasures with respect to the input the decoder. For another example, portions of the received signal having undergone some smaller degree of interference, but some interference nonetheless, may be de-weighted before being provided to the decoder.03-17-2011
20110064172Systems and Methods for Serial Cancellation - A receiver in a CDMA system comprises a front end processor that generates a combined signal per source. A symbol estimator processes the combined signal to produce symbol estimates. An S-Matrix Generation module refines these symbol estimates based on the sub channel symbol estimates. An interference canceller is configured for cancelling interference from at least one of the plurality of received signals for producing at least one interference-cancelled signal.03-17-2011
20110064171MULTI-CARRIER AMPLIFIER LINEARIZATION SYSTEM AND METHOD - The invention relates to a method and circuit for linearizing amplifiers and other nonlinear circuits for multi-carrier signals. An output signal from the amplifier is sampled, and a correlation matrix of size N×N is computed from the sampled signal, wherein N exceeds the number of multiplexed carriers in the signal. A signal-to-distortion ratio (SDR) is then estimated based on a ratio of one or more largest to one or more smallest eigenvalues of the correlation matrix, and the signal into the amplifier is pre-distorted so as to maximize the SDR.03-17-2011
20110064170APPARATUS AND METHOD FOR ESTIMATING A CHANNEL IN A BROADBAND WIRELESS COMMUNICATION SYSTEM - Channel estimation in a broadband wireless communication system is provided. A receiver includes a frequency interpolator for interpolating in a frequency axis using at least one of channel estimation values estimated through pilot signals and channel estimation values generated using a time-axis interpolation, a determiner for determining a compensation coefficient to compensate for edge distortion using the channel estimation values estimated through the pilot signals, and a compensator for generating a completed channel estimation value by multiplying a channel estimation value generated by interpolating in the frequency axis, by the compensation coefficient.03-17-2011
20120114085CHANNEL ESTIMATION METHOD AND APPARATUS - A method and apparatus for estimating a channel efficiently though pilot subcarrier signal transformation and noise reduction in the mobile communication system are provided. The apparatus includes a time domain transformer for transforming received pilot subcarrier signals to time domain signals, a noise reducer for reducing noises of the time domain signals, a frequency domain transformer for transforming the noise-reduced time domain signals to frequency domain signals, and a final channel estimator for estimating channel values of data subcarriers received using the frequency domain signals. The channel estimation method and apparatus of improves performance with the reduction of computational complexity.05-10-2012
20120114084METHODS AND APPARATUS FOR LOW COMPLEXITY SOFT-INPUT SOFT-OUTPUT GROUP DETECTION - Certain aspects of the present disclosure propose methods and apparatus for low complexity soft-in soft-out detection that divide a plurality of received symbols into a plurality of groups of symbols and performs preprocessing on the symbols in each group to suppress interference from other groups. The preprocessing may utilize a priori information for one or more symbols in one or more groups that are not yet detected, and/or a posteriori information for one or more symbols in one or more groups that are already detected and/or decoded. The preprocessed symbols may then be detected using a soft-in soft-out detection algorithm.05-10-2012
20120027137RECEIVER SECOND ORDER INTERMODULATION CORRECTION SYSTEM AND METHOD - A system for correcting a second order intermodulation product in a direct conversion receiver is provided. The system includes a cross-covariance system receiving a data signal and a second order intermodulation estimate signal and generating a cross-covariance value. An auto-covariance system receives the second order intermodulation estimate signal and generates an auto covariance value. A buffer system stores a second order intermodulation product correction factor. A divider receives the cross-covariance value, the auto-covariance value and the second order intermodulation product correction factor and generates a running average second order intermodulation product correction factor.02-02-2012
20120027138Interference cancellation in variable codelength systems for multi-access communication - A receiver employs low-rate processing to synthesize the effect of high-rate interference in a received multi-rate signal. Each high-rate subchannel is analyzed on its low-rate descendents to produce symbol estimates for each low-rate symbol interval. The symbol estimates are applied to low-rate descendent subchannels, which are then combined to synthesize the effects of the high-rate interference. An interference canceller processes the synthesized interference with the received signal for producing an interference-cancelled signal. Alternatively, analogous steps may be applied at high-rate to analyze, synthesize, and cancel the effects of low-rate interference in a multi-rate signal.02-02-2012
20120063552Electro-magnetic Interference Reduction for Switched Signal Systems - In one embodiment, a method receives a pulse width modulation signal. A value that is a function of the pulse width modulation signal is determined. The value is used to modulate a switching frequency of the pulse width modulation signal to generate a modulated pulse width modulation signal. The applied value reduces electro-magnetic interference from tones in the modulated pulse width modulation signal.03-15-2012
20090135972INTERFERING SIGNAL CHARACTERIZING QUANTITY STORING METHOD AND DEVICE, INTERFERING SIGNAL CHARACTERIZING QUANTITY ACQUIRING METHOD AND DEVICE, AND INTERFERING SIGNAL SUPPRESSING METHOD AND DEVICE - An object is to identify interfering signals coming at random timings from different radio stations. In order to attain this object, a method for storing the characterizing quantity of an interfering signal included in a received signal comprises a characterizing quantity calculation step of calculating the characterizing quantity of the received signal; a received signal determination step of determining a probability that a desired signal is included in the received signal, and determining that the received signal is an interfering signal when determining that there is no probability that the desired signal is included in the received signal; and an interfering signal characterizing quantity storage step of storing the characterizing quantity of the received signal as an interfering signal characterizing quantity when it is determined at the received signal determination step that there is no probability that the desired signal is included in the received signal.05-28-2009
20120250809RADIO FREQUENCY (RF) RECEIVER WITH DYNAMIC FREQUENCY PLANNING AND METHOD THEREFOR - A radio frequency (RF) receiver comprises an analog receiver, a digital processor, a clock synthesizer, and a microcontroller. The analog receiver has an input for receiving an RF input signal, and an output for providing a digital intermediate frequency (IF) signal. The digital signal processor has a first input for receiving the digital IF signal, a second input for receiving a clock signal, and a signal output for providing an IF output signal. The clock synthesizer has an input for receiving a clock control signal, and an output for providing the clock signal. The a microcontroller has an input for receiving a channel selection signal, wherein the microcontroller provides the clock control signal to control a frequency of the clock signal dynamically in response to a channel selection input to reduce interference of sub-harmonics created by the clock signal on the analog receiver.10-04-2012
20120250808ARCHITECTURE AND METHOD OF CHANNEL ESTIMATION FOR WIRELESS COMMUNICATION SYSTEM - An apparatus may comprise a channel estimation architecture for wireless communications. Other embodiments are described and claimed.10-04-2012
20100158171Estimation of noise variance combined with narrow-band interference detection - Method and apparatus are provided for estimating noise variance using a long-term data aided algorithm and an interference variance using a short-term data aided algorithm. Using these estimations, an interference hypothesis may be determined. Some embodiments compute the variance for a decision directed noise sample, convert the variance for the decision directed noise to a true noise variance per packet, and convert the variance for the decision directed noise to a true noise variance per symbol. The interference hypothesis may be based on the noise variance estimations per symbol and the noise variance estimation per packet. Some embodiments determine the presence of noise based on a comparison of the noise variance per packet, the noise variance per symbol, and each hypothesis and compute the long-term noise variance. Using the long-term noise variance in place of the variance for a decision directed noise sample for a subsequent determination of interference.06-24-2010
20110103531SYSTEM AND METHOD FOR RADIO SIGNAL RECONSTRUCTION USING SIGNAL PROCESSOR - A waveform reconstruction circuit receives an rf signal from an antenna, digitizes it, and then generates an undistorted reconstructed waveform. The reconstructed waveform can then be conventionally mixed and demodulated to extract useful signal information with enhanced receiver fidelity and sensitivity.05-05-2011
20100290570METHOD AND APPARATUS FOR CHANNEL ESTIMATION IN OFDM - The present invention relates to methods that can be used in a wireless communication system, and systems adapted to use such methods. In a preferred form the methods are useful in channel estimation in a wireless communication system using orthogonal frequency division multiplexing (OFDM). The system is provided with a control block to optimise channel estimation.11-18-2010
20100208853FEEDBACK ADJUSTABLE CONSTELLATION DE-MAPPER - A system and method to adjust the symbol constellation used to de-map a signal in an optical coherent communications system. A feedback de-mapper adjustment module is configured to compare average Error Vector Magnitude and Bit Error Ratio to a pre-defined table to determine when a constellation de-mapper mismatch occurs. The feedback de-mapper adjustment module then rotates the de-mapper constellation in order to compensate for phase drift.08-19-2010
20110182389JITTER COMPENSATION - The present invention relates to a circuit and a method for jitter compensation in a receiver system and for improving the SNR and/or the BER performance. The circuit for jitter compensation comprises: a combiner block (07-28-2011
20120170696RECEIVER - A receiver includes: a first mixer that generates an in-phase signal from a received signal; a second mixer that generates a quadrature signal from the received signal; a first A/D converter that converts the in-phase signal into a digital in-phase signal; a second A/D converter that converts the quadrature signal into a digital quadrature signal; a calculator that calculates an addition/subtraction quantity based on a correction quantity, which is based on an amplitude value of the digital in-phase signal or the digital quadrature signal, and a quantization error of the first A/D converter or the second A/D converter; and an addition/subtraction unit that adds or subtracts the addition/subtraction quantity to or from the digital in-phase signal or the digital quadrature signal.07-05-2012
20120076248Covariance Factor Matrix Reuse - A method and apparatus for reducing the computational load associated with computing weighting factors for wireless signals received at a wireless receiver is disclosed herein. The method and apparatus reuses a covariance factor matrix to compute multiple sets of weighting factors for multiple received signals. Particular embodiments factor a covariance matrix determined for a first received signal to determine a covariance factor matrix, and use the covariance factor matrix to determine a set of weighting factors for the first received signal as well as to determine additional sets of weighting factors for one or more additional received signals. The different received signals may be associated with different times, different channelization codes, and/or different frequencies. The weighting factors may be used to weight and combine received signals in a GRAKE receiver or chip equalizer. The weighting factors may also be used to determine a signal quality metric.03-29-2012
20120314822INTERFERENCE RESISTANT COMPRESSIVE SAMPLING - Embodiments provide for dramatically improved interference resistance in advanced communications applications, where the frequency range can exceed 1 GHz. Such embodiments may be implemented using wideband technology to provide a wideband compressive sampling architecture that is capable of superior interference rejection through RF front end cancellation.12-13-2012
20100272220Multi-Antenna Receiver Interference Cancellation Method and Apparatus - A composite signal including a plurality of component signal streams is processed using QR-decomposition to detect symbols and calculate a decision metric for each of the signal streams (10-28-2010
20100008455Monitoring of an Antenna System - The present invention relates to a method and apparatus for monitoring an antenna system comprising at least two antenna branches providing antenna diversity. At least a first signal branch measure and a second signal branch measure are repeatedly generated in response to a first signal branch and a second signal branch received by a respective one of the at least two antenna branches, thus generating a first plurality of first signal branch measure values and a second plurality of second signal branch measure values in a manner so that the first and second pluralities reflect the quality of the first and second signal branches, respectively, at different points in time. The first and second pluralities are analysed in order to distinguish any differences in the performance of the first and second antenna branches.01-14-2010
20100008454Method for compensation of information losses in an OFDM-based multi-carrier communication signal caused by blanking out pulse-shaped interferences - A method for compensation of information losses caused by blanking out pulse-shaped interferences in a communication signal, wherein a receiver receives a modulated OFDM-based signal comprising an overlap of a sequence of a predetermined number of subcarrier signals whose frequencies differ by a constant amount and which have substantially no signal portions at the frequencies of the respective other subcarrier signals, and pulse-shaped interference signals. The pulse-shaped interference signals are eliminated by pulse blanking. The obtained signal in the frequency domain is characterized in that the signal portions at each subcarrier frequency consist of an overlap of determinable signal portions respectively of all other subcarrier signals. From the respective signal portion at a subcarrier frequency, those determinable signal portions are subtracted in the frequency domain which result from the subcarrier signals of all other subcarriers and are reconstructed from an estimation of the complex data symbols transmitted on each subcarrier.01-14-2010
20090296863Interference Estimator - A method of detecting a data stream comprising estimating a data stream from a received signal, generating an interference estimate based on said estimated data stream, detecting the data stream using said interference estimate.12-03-2009
20120257697METHOD AND APPARATUS FOR IDENTIFYING CO-CHANNEL INTERFERENCE - Methods and apparatuses identifying a co-channel interference signal in communications systems are disclosed. An exemplary method comprises generating an interference signal by subtracting a reconstructed desired signal from an at least partially demodulated composite signal, and generating synchronization statistics of interference signal using different scrambling codes. The interference signal is identified as the signal associated with the scrambling code that was used to generate an interference signal having a desired synchronization statistic.10-11-2012
20120082274METHOD FOR PROCESSING RECEIVED OFDM DATA SYMBOLS AND OFDM BASEBAND RECEIVER - A method is provided for processing received data symbols in an orthogonal frequency division multiplexing (OFDM) transmission scheme, and an OFDM baseband receiver which performs this method, in order to support frequency selective noise estimation, especially in interference limited environments, and to offer improved estimation performance and reduced computational complexity. This is achieved by determining time and frequency selective levels of combined noise and interference, computing noise normalization values for a respective time-frequency region of the time-frequency plane that applies in the transmission scheme employed, from said time and frequency selective noise plus interference levels, applying said noise normalization values to the received data symbols to obtain normalized data symbols, applying said noise normalization values to the channel estimates, to obtain normalized channel estimates, determining communication parameter estimates from said normalized channel estimates, and determining demodulated and decoded data from said normalized data symbols using said normalized channel estimates.04-05-2012
20120082273CHANNEL QUALITY DETERMINING CIRCUIT AND RELATED METHOD THEREOF - A channel quality determining circuit includes a receiving circuit and a determining circuit. The receiving circuit is used for receiving a header of at least one packet transmitted in a signal transmitting channel. The determining circuit is coupled to the receiving circuit, and used for determining if a channel quality of the signal transmitting channel satisfies a predetermined quality standard according to the header of at least one packet.04-05-2012
20120082272SELECTABLE INTERFERENCE CANCELLATION IN A COMMUNICATIONS RECEIVER - Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions.04-05-2012
20090016471Impulse Noise Detection and Mitigation In Receivers - Methods and apparatus, including computer program products, are provided for detecting and mitigating noise, such as impulse noise. In one aspect, there is provided a noise suppressor to determine a predicted value for a sample in a bit stream, the predicted value determined without regard to an average of the bit stream. The noise suppressor may also detect whether impulse noise is present based on a difference between the predicted value and the sample. The noise suppressor may also identify the sample as impulse noise to enable the sample to be replaced with another value.01-15-2009
20090016472METHOD AND APPARATUS FOR SIGNAL QUALITY ESTIMATION - A receiver (01-15-2009
20110122977SELF-COMPENSATING DRIFT-FREE HIGH-FREQUENCY PHASE DETECTOR CIRCUIT - The present invention relates to a phase detector circuit (05-26-2011
20080298523REDUCED COMPLEXITY SLIDING WINDOW BASED EQUALIZER - Data estimation is performed in a wireless communication system using both oversampling and multiple reception antennas. A receive vector is produced for each antenna at a sampling interval which is a multiple of the chip rate of the received signal. A channel response matrix is produced for each antenna at a preferred multiple of the sampling rate. Each receive vector is processed using a sliding window based approach, where a plurality of successive windows are processed. For each window, a combined circulant channel response matrix is produced using the channel response matrices. Using the combined circulant channel response matrix and a combined received vector comprising each received vector in a discrete Fourier transform based approach to estimate a data vector corresponding to that window; and combining the data vector estimated in each window to form a combined data vector.12-04-2008
20080298522METHOD AND APPARATUS FOR COMPUTING SIR OF TIME VARYING SIGNALS IN A WIRELESS COMMUNICATION SYSTEM - A method and apparatus for correcting symbols of a common pilot channel (CPICH) to generate an accurate signal-to-interference ratio (SIR) estimate in a wireless communication system are disclosed. In one embodiment, a non-stationary mean of a group of the CPICH symbols is estimated, the CPICH symbols are delayed, and the CPICH symbols are corrected by dividing the delayed CPICH symbols by the estimated non-stationary mean of the group of CPICH symbols. In another embodiment, a signal power estimate is generated based on the magnitude of CPICH symbols, a noise power estimate is generated by subtracting the signal power estimate from a total power estimate based on the magnitude of the CPICH symbols, and a SIR estimate is generated for symbols that have undergone a time varying gain by dividing the signal power estimate by the noise power estimate.12-04-2008
20080298521INTERFERENCE SUPPRESSION PROCESSING UNIT AND A METHOD OF SUPPRESSING INTERFERENCE IN WIRELESS DATA COMMUNICATION - The interference suppression processing unit includes N12-04-2008
20110038447RECEPTION DEVICE, INTEGRATED CIRCUIT, AND RECEPTION METHOD - An OFDM demodulation unit 02-17-2011
20110038446Method and Device for Processing Received Data of a Radio Interface - The invention relates to an apparatus and method for processing received data (I02-17-2011
20110038445COMMUNICATIONS CHANNEL ESTIMATION - Techniques for estimating the response of a communications channel. In an aspect, a channel autocorrelation matrix is derived based on, e.g., certain assumptions about the time delay profile, Doppler profile. An eigenvector decomposition is performed on the autocorrelation matrix, and a set of dominant eigenvectors is determined. A received pilot signal vector is projected onto a projection matrix derived from the dominant eigenvectors to generate a set of eigen-coefficients, which is then used to reconstruct an estimated channel vector. In an exemplary embodiment, the eigenvector-based approach is combined with a simplified minimum mean-square error based approach to generate an estimated channel vector when the received signal-to-noise ratio is below a threshold.02-17-2011
20120321025ITERATIVE CHANNEL ESTIMATION METHOD WITH COMPENSATED MMSE - A channel estimation treatment method and device for obtaining binary data conveyed in a signal. The method includes: obtaining a current vector of channel estimates, each element of the current vector corresponding to an estimate of a subchannel; detecting, inside the current vector, at least one pilot symbol; splitting the current vector in at least two subvectors, at least one first subvector including channel estimates related to data symbols and/or pilots symbols and at least one second subvector including channel estimates related to null symbols; decoding the at least one first subvector, delivering at least one first treated subvector; modifying the at least one second subvector by assuming presence of pilot symbols in the at least one second subvector, delivering at least one second treated subvector; and calculating a new vector of channel estimates with the at least one first treated subvector and the at least one second treated subvector.12-20-2012
20120321024METHOD AND SYSTEM TO ADAPTIVELY CANCEL SINUSOIDAL INTERFERENCE FROM A SIGNAL PROCESSING SYSTEM - A method of canceling sinusoidal interference from a received signal includes identifying a block of signal-free data containing sinusoidal interference. A model of the significant interference in the selected data block is constructed, scaled to subsequent data blocks and used to remove sinusoidal interference signals from the overall received signal.12-20-2012
20100226464METHOD AND APPARATUS FOR ELIMINATING FREQUENCY-DOMAIN INTERFERENCE SIGNALS - The present invention discloses a method and an apparatus for eliminating frequency-domain interference signals, and relates to communication technologies. The method includes: multiplying a frequency-domain channel estimation value by a frequency-domain interference signal to obtain a frequency-domain received interference signal; and subtracting the frequency-domain received interference signal from the frequency-domain received signal to obtain the frequency-domain received signal free of interference. The apparatus includes a multiplying module and a subtracting module. A frequency-domain equalizer includes an interference signal obtaining module and an interference signal eliminating module. The technical solution provided herein eliminates interference signals in the frequency domain, and saves the calculation load in contrast with elimination of time-domain interference signals.09-09-2010
20100232554PREDICTIVE SIGNAL CANCELLATION FOR EXTRACTING 1 MB/s MIL-STD-1553 COMPONENT FROM COMPOSITE HIGH PERFORMANCE 1553 SIGNAL - Method and apparatus for maximizing the usable bandwidth for High Performance 1553 terminals operating concurrently on the same physical bus with legacy 1 Mb/s MIL-STD-1553 terminals. More specifically, the method and apparatus provides implementation for predictive cancellation by synthesizing an estimate of the 1 Mb/s MIL-STD-1553 component of a composite 1 Mb/s plus High Performance 1553 input signal using either of two different techniques: (1) a combination of digital and analog techniques; and (2) an all digital technique. The synthesized signal is then subtracted from the composite signal. Both techniques employ an algorithm for minimizing the effects of clock skew between 1 Mb/s 1553 transmitting clocks and the local High Performance 1553 sampling clock. Both techniques also incorporate an adaptation algorithm for developing and maintaining digital models of 1 Mb/s 1553 signals received from multiple 1 Mb/s 1553 terminals on a bus.09-16-2010
20100232553MULTI - USER MULTIPLE INPUT MULTIPLE OUTPUT (MU - MIMO) RECEIVER - Some of the embodiments of the present disclosure provide a method within a wireless communication network, the method comprising, receiving by a user equipment (UE), a signal and interference component, wherein the interference component was transmitted in an unknown direction; and decoding, by the UE, the signal based at least in part on the interference component. Other embodiments are also described and claimed.09-16-2010
20110243284Delay Restricted Channel Estimation for Multi-Carrier Systems - A method includes performing a channel estimation to obtain an estimate of the channel based on a received signal. A subset of elements of the estimate are suppressed to obtain a suppressed estimate of the channel. The method includes multiplying the suppressed estimate of the channel by a matrix to obtain a delay restricted estimate of the channel.10-06-2011
20120087450WIRELESS COMMUNICATION NODE CONNECTIONS - The present invention relates to a wireless communication node (04-12-2012
20120087449METHODS AND APPARATUS FOR SYNCHRONIZATION IN MULTIPLE-CHANNEL COMMUNICATION SYSTEMS - Methods and apparatus for processing multichannel signals in a multichannel receiver are described. In one implementation, a plurality of demodulator circuits may provide a plurality of outputs to a processing module, with the processing module then simultaneously estimating noise characteristics based on the plurality of outputs and generating a common noise estimate based on the plurality of outputs. This common noise estimate may then be provided back the demodulators and used to adjust the demodulation of signals in the plurality of demodulators to improve phase noise performance.04-12-2012
20120328059RECEIVER CIRCUIT AND METHOD - A receiver circuit includes an estimation unit configured to estimate a noise power of a transmission channel, a calculation unit configured to calculate a decision variable based on the noise power, and a decision unit configured to make a ternary decision based on the decision variable.12-27-2012
20100202576Apparatus For, and Method of, Reducing Noise in a Communications System - A communication line having a plurality of twisted wire pairs connects a plurality of transmitters, one transmitter at each end of each twisted wire pair, with a plurality of receivers, one receiver at each end of each twisted wire pair. Each receiver receives a combination signal including a direct signal from the transmitter at the opposite end of the twisted wire pair with which the receiver is associated and a plurality of far-end crosstalk (FEXT) impairment signals, one from each of the remaining transmitters at the opposite end of the communications line. A plurality of FEXT cancellation systems, one associated with each receiver, provides a replica FEXT impairment signal. A device associated with each receiver is responsive to the combination signal received by the receiver and the replica FEXT impairment signal provided by the FEXT cancellation system associated with the receiver for substantially removing the FEXT impairment signals from the combination signal. If necessary, a skew adjuster delays the arrival of the combination signal at the device so that the combination signal and the FEXT impairment signal arrive at the device at substantially the same time. A sequential decoder operates on signals from each of the plurality of wire pairs simultaneously to produce receiver outputs. A plurality of near-end crosstalk (NEXT) cancellation systems and echo cancellers remove NEXT and echo impairment signals from the combination signal.08-12-2010
20130010907Selecting from Among Plural Channel Estimation Techniques - A wireless receiver receives reference signals over a wireless link The wireless receiver calculates a selection indication based on the received reference signals, and the wireless receiver selects from among plural channel estimation techniques based on the selection indication, where the selected channel estimation technique is usable to perform channel estimation of the wireless link.01-10-2013
20130010906Method and System for Delay Locked Loop for Rake Receiver - Certain aspects of a method and system for a delay locked loop for a rake receiver are disclosed. Aspects of one method may include normalizing a signal power of a first control channel based on a threshold value. A sampling time associated with at least one or more of the following: the first control channel, a second control channel, an on-time control channel, and a data channel, may be adjusted based on a comparison between the normalized signal power of the first control channel and a signal power of the second control channel. The second control channel may be delayed with respect to the first control channel by a particular time period. The first and second control channels may be common pilot control channels (CPICHs). The combined signal power of the first control channel may be normalized based on said threshold value.01-10-2013
20110158360SNR-Based Blanking Scheme for Impulsive Noise Mitigation in Wireless Networks - A blanking scheme for mitigating impulsive noise in wireless networks is based on the signal-to-noise ratio (SNR) of symbols. To fully gain the benefits of the SNR-based blanking scheme, two methods are developed, namely a multi-level thresholding scheme in the time-, spatial- and frequency-domains, and a weighted-input error-correction decoding. The symbols are conditioned as a function of the estimated SNR in time-, frequency-, or spatial-domains or combinations therefore, and the conditioning is applied to an amplitude, phase, or energy level, or combinations thereof.06-30-2011
20110158359ITERATIVE DECODING AND DEMODULATION WITH FEEDBACK ATTENUATION - An iterative demodulator and decoder uses feedback attenuation to maintain proper balance between the demodulator and decoder. Balance is maintained by attenuating the influence of extrinsic information fed back from the decoder to the demodulator to prevent strong decisions by the decoder from overwhelming the demodulator.06-30-2011
20130022160APPARATUS AND METHOD FOR ADAPTIVE WHITENING IN A MULTIPLE ANTENNA SYSTEM - An apparatus and method for controlling a whitening function of a whitening Maximum Ratio Combining (MRC) in a receive end of a multiple antenna system are provided. The method includes identifying if there is interference from at least one neighbor cell, if there is interference, generating a weight of the whitening MRC using a pre-whitening inverse matrix, and, if there is no interference, generating a weight of the whitening MRC using a unit matrix, thus being capable of improving a reception performance of the receive end.01-24-2013
20120243648Characterization and assessment of communication channel average group delay variation - Characterization and assessment of communication channel average group delay variation. A signal having repeated signal components therein is received by a communication device, and that signal undergoes appropriate processing to determine respective amplitude and phase of a number of frequency bins. The phase difference from bin to bin (including respecting unwrapping, and proper normalization) is used to determine the group delay of a communication channel, or portion thereof, as a function of frequency. Multiple respective group delay measurements may be averaged to generate a wideband group delay of the communication channel as a function of frequency. Overlap between different respective band-edge portions of the communication channel may assist in generating a seamless continuous wideband spectrum estimation for use in determining the wideband group delay of the communication channel.09-27-2012
20080253489Apparatus and Method for interference cancellation in receiver of communication system - An apparatus and method for interference cancellation is provided to cancel the interference such as echo and cross-talk received by a receiver of a communication system. The apparatus includes a digital cancellation signal generator, a first canceller, and a second canceller. The digital cancellation signal generator can generate a digital cancellation signal, which includes a first and a second portion and represents an interference signal within a received signal. The first canceller can perform an analog cancellation on the received signal to output a partially-interference-canceled received signal according to the first portion of the digital cancellation signal. The second canceller can perform a digital cancellation on the partially-interference-canceled received signal according to the second portion of the digital cancellation signal.10-16-2008
20090141840Impulse noise identification method and system - Apparatus for detecting impulse-type noise in a received signal comprises a decoder unit for sampling the signal and decoding to produce symbols, and an analysis unit for analyzing a distribution of the distances between the decoded symbols and the respective samples. The distribution is indicative of noise type, and thus can be analyzed to produce an output when the distribution indicates that the noise is impulse noise. If QAM is the decoding system, then for each decoded symbol there is a distance between the input and the decoded symbol, and the distribution of the distance indicates the type of noise. A random distribution is taken as indicative of the impulse noise.06-04-2009
20080232520METHOD AND APPARATUS FOR EYE-OPENING BASED OPTIMIZATION - An eye opening measurement technique, that does not interrupt a receiver's normal operation, is used as a metric for optimizing any selected parameters of the receiver's operation. If eye opening size decreases, as a result of a change to a receiver parameter, the polarity for stepwise changes is reversed such that the next change is in the opposite direction. Other types of search procedures can be used.09-25-2008
20080232519METHOD AND APPARATUS FOR COMPENSATING CHANNEL CHANGES FOR FAST FADING CHANNELS - A method for compensating channel changes in an OFDM system is provided. The method comprises the steps of: providing at least two PN sequences; and using the parameters of the at least two PN sequences for determining a set of compensated values of data disposed between the at least two PN sequences.09-25-2008
20080225999System and method for broadband pulse detection among multiple interferers using a picket fence receiver - A system and method to detect broadband pulses in the presence of multiple arrow band interferers is disclosed whereby a picket fence filtering method is detect and ignore the signal at the precise location of the narrow band interferers.09-18-2008
20080225998APPARATUS AND METHOD FOR ESTIMATING NOISE POWER IN FREQUENCY DOMAIN - An apparatus and a method for estimating noise power in frequency domain are provided. The apparatus and the method are applied to a state where no packet is transmitted over the channels. And the apparatus and the method acquire noise in every sub-carrier, and obtain the transmission status in every sub-channel to adjust bit-loading in every sub-carrier and improve the spectral-efficiency.09-18-2008
20130156141DIGITAL RADIO FREQUENCY (RF) RECEIVER - A digital RF receiver does not use a separate receiver according to a mode and a band for multi-mode reception, MIMO reception, and bandwidth extension reception, and changes only setting variables in a single receiver structure so as to implement multi-mode reception, MIMO reception, bandwidth extension reception, and/or simultaneous multi-mode operation, such that complexity of the receiver, development cost, and power consumption can be reduced.06-20-2013
20130177114METHOD OF DETECTION OF SIGNAL IN COMMUNICATION SYSTEMS WITH MIMO CHANNEL - An apparatus and a method for detecting signals are provided. The method for detecting signals in a receiving end having a plurality of antenna in wireless communication system includes performing Minimum Mean Square Error (MMSE) estimation for a transmitted symbol vector, determining a covariance matrix for the MMSE estimation, determining a triangular matrix based on the covariance matrix, and determining accumulated metrics for each symbol vector candidate based on the triangular matrix.07-11-2013
20110274225METHOD AND SYSTEM FOR DENOISING SIGNALS - The application is directed to generally applicable denoising methods and systems for recovering, from a noise-corrupted signal, a cleaned signal equal to, or close to, the original, clean signal that suffered corruption due to one or more noise-inducing processes, devices, or media In a first pass, noise-corrupted-signal-reconstruction systems and methods receive an instance of one of many different types of neighborhood rules and use the received neighborhood rule to acquire statistics from a noisy signal. In a second pass, the noise-corrupted-signal-reconstruction systems and methods receive an instance of one of many different types of denoising rules, and use the received denoising rule to denoise a received, noisy signal in order to produce a cleaned signal.11-10-2011
20080219387CROSS QAM MODULATION-BASED SYMBOL MAPPING METHOD AND APPARATUS IN A MOBILE COMMUNICATION SYSTEM - A method for determining a bit pattern of a symbol in a wireless communication system using a cross modulation scheme. The method includes generating symbols with the cross modulation scheme, classifying positions of coding symbols by reliabilities of at least 3 classes according to an average bit error rate BER(ave) of symbols generated with the cross modulation scheme and a bit error rate BER based on transmission positions of the coding symbols in a modulation symbol during transmission of a packet with the cross modulation scheme, and determining a bit pattern such that higher-priority symbols are inserted into higher-reliability positions.09-11-2008
20130114768INTERFERENCE MITIGATION METHOD FOR SINGLE OR MIMO RECEIVER DEVICES - A cognitive radio signal processing method suitable for single receiver devices where interference is mitigated using projection of received multi-dimensional signal space to maximize SNR by orthogonalizing interference is described. The method is based on a well-known LMS solution that is computed from received multi antenna and multicarrier signals in a novel way. This method solves the requirement of multiple RF chains in low cost handsets by introducing a protocol synchronous antenna switcher that allows, for example, a LTE handset with a single antenna to benefit from algorithms that typically require multiple receivers for the same frequency, i.e. MIMO.05-09-2013
20130114767APPARATUS AND METHOD FOR ENHANCING CHANNEL ESTIMATION ACCURACY IN COMMUNICATION SYSTEM - An apparatus and method for calculating a correlation value using a first channel impulse response estimated from a received signal, determining a weight value based on the correlation value, applying the weight value to the first channel impulse response, and estimating a second channel impulse response is provided.05-09-2013
20130121448CHANNEL ESTIMATION AND EQUALIZATION FOR HARD-LIMITED SIGNALS - The present invention provides a method and apparatus for channel estimation when the amplitude of a received signal is hard-limited. A channel estimator computes amplitude estimates for the received signal based on the phase samples of the received signal. The amplitude estimates may comprise the expected values of the amplitude given the phase samples. The channel estimator then computes revised channel estimates based on the amplitude estimates and the phase samples. The process may be performed iteratively to refine the channel estimates during each iteration.05-16-2013
20130129023CHANNEL ESTIMATION METHOD AND SYSTEM BASED ON TIME-DOMAIN TRAINING SEQUENCE - A channel estimation method and a channel estimation system based on time-domain training sequence are provided. The channel estimation system first acquires an initial channel vector used for channel estimation of a current frame, and calculates an algorithm initial vector based on a training sequence vector contained in a received receiving signal vector and the receiving signal vector, then performs estimation based on the initial channel vector and the algorithm initial vector and using a conjugate gradient method based on a preprocessing matrix to acquire each channel estimation value, and eventually perform noise reduction processing on each channel estimation value based on a first predetermined threshold value to acquire a final channel estimation value. Compared with the existing channel estimation methods, the present invention has a shorter delay and lower calculation complexity, and thus can be easily implemented.05-23-2013
20080205561Apparatus and method for interference cancellation in broadband wireless access communication system - Provided are an apparatus and method for interference cancellation in a BWA communication system. In a receiving apparatus for the interference cancellation, a preamble correlation measurer measures a preamble correlation coefficient from a preamble of a signal received signal. A data rearranger determines a block size to divide the received signal from the preamble correlation coefficient, divides the signal according to the determined block size, and rearranges the divided signals in a Space-Time coding (STC) mode. An estimate weight calculator cross-correlates the output signals of the data rearranger, rearranges the cross-correlated signals, auto-correlates the rearranged signals, and calculates an estimate weight to perform an interpolation operation. An estimate signal decoding/combining unit detects desired signals from signals estimated by the estimate weight calculator and combines the detected signals.08-28-2008
20130148767CYCLIC PREFIX AND PRECURSOR JOINT ESTIMATION - A method of operating a communications system includes generating a channel impulse response estimate based on a first received signal. The method includes selecting a precursor and a cyclic prefix length for a second received signal based on the channel impulse response estimate, a target cyclic prefix energy level, and a predetermined range of cyclic prefix lengths.06-13-2013
20100284499Estimating a Signal-to-Interference Ratio in a Receiver of a Wireless Communications System - A Signal-to-Interference Ratio of a radio channel is estimated in a receiver of a wireless communications system, wherein pilots with reference information are modulated on some sub-carriers in some symbols. At least one parameter for signals received from said first transmitter is detected, and a number (N11-11-2010
20130188760METHODS AND APPARATUS FOR REDUCING AND/OR ELIMINATING THE EFFECTS OF SELF-INTERFERENCE - Methods and apparatus for reducing and/or eliminating the effect of self-interference are described. Various described methods and apparatus are well suited for use in DSRC WAVE systems in which a wireless communications device may acquire and use two DSRC channels, e.g., use one channel for reception while using another channel for transmission at the same time. A wireless communications device which is receiving a signal of interest on a first channel supports concurrent transmission on second channel, e.g., an adjacent channel. Controlled transmission timing synchronization with respect to the received signal of interest facilitates interference estimation and removal. Interference due to spillover energy from the transmission on the adjacent channel is estimated and removed from a received signal to facilitate recovery of the signal of interest.07-25-2013
20080212724Wireless communications system having reduced noise mode operation capability - A wireless communication system having a terminal unit operates in a reduced noise state during receipt of a wireless transmission from a control unit. The terminal unit includes terminal circuitry, a radio and noise management circuitry. The noise management circuitry partially or fully disables operation of the terminal circuitry during a receipt by the radio. Noise management circuitry may disable a terminal processor, disable interrupts, buffer interrupts and otherwise modify operation of the terminal circuitry to reduce generated radio noise that would otherwise interfere with receipt of data by the radio. The wireless communication system includes noise management circuitry located in a control unit that operates in conjunction with noise management circuitry in a first terminal unit and a second terminal unit to schedule transmissions from the control unit. These scheduled transmissions allow the terminal units to perform required processing functions outside of the reduced noise period.09-04-2008
20120020442METHOD AND AN APPARATUS FOR DECONVOLUTING A NOISY MEASURED SIGNAL OBTAINED FROM A SENSOR DEVICE - The present invention relates to a method and apparatus for deconvolving a noisy measured signal obtained from a sensor device (01-26-2012
20130195232Interference Cancellation for Non-Orthogonal Channel Sets - Techniques for interference cancellation in a CDMA system. In an exemplary embodiment, a channel set scrambled using a secondary scrambling code (SSC) is estimated and cancelled along with a channel set scrambled using a primary scrambling code (SSC). The estimation and cancellation of the SSC channel set may proceed in series with the estimation and cancellation of the PSC channel set. Alternatively, the estimation of the SSC channel set may proceed in parallel with the estimation of the PSC channel set, and the cancellations of the PSC and SSC channel sets may be simultaneously performed. Multiple iterations of such estimation and cancellation may be performed in a successive interference cancellation (SIC) scheme.08-01-2013
20130094621Method and System for Channel Estimation Processing for Interference Suppression - Aspects of a method and system for channel estimation for interference suppression are provided. In this regard, one or more circuits and/or processors of a mobile communication device may generate and/or receive a first set of channel estimates and a second set of channel estimates. The one or more circuits and/or processors may modify the second set of channel estimates based on a comparison of a measure of correlation between the first set of channel estimates and the second set of channel estimates with a threshold. The first set of channel estimates and/or the modified second set of channel estimates may be utilized for cancelling interference in received signals. The first set of channel estimates may be associated with a first transmit antenna of a base transceiver station and the second set of channel estimates may be associated with a second transmit antenna of the base transceiver station.04-18-2013
20120093271CHANNEL ESTIMATION APPARATUS, CHANNEL ESTIMATION METHOD AND PROGRAM - A channel estimation device comprises: a channel variation detection unit that determines whether variation width of a received signal level is not less than preset threshold width and whether variation period of received signal is not greater than preset threshold period; and a channel estimation unit that, if the channel variation detection unit determines that the variation width of the received signal level is not less than preset threshold width and that variation period is not greater than preset threshold period, refers to hysteresis of received signal level to determine whether lowering of received signal level is temporal, and, if it is determined that lowering of received signal level is temporal, allowing received signal to pass through, without removing received signal as noise, even when received signal level is not greater than signal level to be removed as noise.04-19-2012
20120093270MULTI-CARRIER RECEIVER WITH DYNAMIC POWER ADJUSTMENT AND METHOD FOR DYNAMICALLY ADJUSTING THE POWER CONSUMPTION OF A MULTI-CARRIER RECEIVER - A method for dynamically adjusting the power consumption of a multi-carrier receiver and a multi-carrier receiver with dynamically power adjustment. The method includes receiving a multi-carrier signal, wherein the multi-carrier signal comprises a plurality of sub-carriers. Channel characteristics of each sub-carrier are estimated according to the demodulated multi-carrier signal. ICI is estimated from the demodulated multi-carrier signal. A system performance is detected. The estimated ICI is subtracted when the ICI exceeds an ICI threshold and the system performance is less than a system performance threshold. The demodulated multi-carrier signal is then equalized is based on the estimated channel characteristics, and the system performance is updated according to the equalized multi-carrier signal.04-19-2012
20120093269APPARATUS 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

Patent applications in class Interference or noise reduction

Patent applications in all subclasses Interference or noise reduction