| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 375231000 | Training period or initial set up | 73 |
| 20080212666 | Interference rejection in radio receiver - An interference rejection algorithm for a radio receiver is presented. According to the present solution a signal comprising a training sequence and a data sequence is received at the radio receiver. A radio channel response may be estimated from the received training sequence, and interference parameters may be estimated from at least one of the received training sequence and the received data sequence, the estimation of the interference parameters comprising smoothing a frequency spectrum of at least one of the estimated channel response and the estimated interference parameters through averaging. Then, frequency domain interference suppression weights are calculated from the estimated channel response and the interference parameters, and weighting of the received data sequence is carried out with the calculated weights. | 09-04-2008 |
| 20080212667 | Graphical user interface for multi-tap delay - A multi-tap delay has a graphical user interface in which each delay tap is represented by a bar on a time line. The bars are oriented across the time line, the position of each bar on the time line specifying the amount of delay time of the represented delay tap. The length of each bar specifies the value of another parameter of the represented delay tap. | 09-04-2008 |
| 20080219338 | QUADRATURE MODULATION ROTATING TRAINING SEQUENCE - A system and method are provided for transmitting a rotating training sequence. A rotating training signal is generated in quadrature modulation transmitter. The rotating training signal includes training information sent via an in-phase (I) modulation path, as well as training information sent via a quadrature (Q) modulation path. The rotating training signal may be generated by initially sending training information via the I modulation path, and subsequently sending training information via the Q modulation path. The training information sent via the I modulation path may include a first symbol having a reference phase (e.g., 0 degrees or 180 degrees). Then, the training information sent via the Q modulation path would include a second symbol having a phase that is ±90 from the reference phase. | 09-11-2008 |
| 20080219339 | CHANNEL ESTIMATION USING FREQUENCY SMOOTHING - A system and method are provided for supplying a frequency-smoothed communications training signal. The method generates a frequency-smoothed unbiased training signal in a quadrature modulation transmitter. The frequency-smoothed unbiased training signal includes a plurality of pilot signal products, where each pilot signal product includes complex plane information represented by a reference frequency subcarrier, multiplying complex plane information represented by mirror frequency subcarrier. The sum of the plurality of pilot signal products is equal to zero. The method supplies the frequency-smoothed unbiased training signal so that it may be transmitted within a single symbol period. System and methods are also provided for using a frequency-smoothed training signal in the calculation of a receiver channel estimate. | 09-11-2008 |
| 20080219340 | FREQUENCY DOMAIN EQUALIZER FOR WIRELESS COMMUNICATIONS SYSTEM - The present invention relates to wireless communications and is particularly applicable to devices and modules for correcting errors introduced to a wireless signal after its transmission. An equalizer is provided which compensates for undesirable effects on received radio signals introduced by either signal processing or by the transmission medium. In operation, the equalizer multiples the complex received signal with a complex corrective signal that compensates for these effects. A tap corrective signal corrects for time-varying channel effects (i.e. channel distortions), a timing tracking signal corrects for carrier frequency offset errors, and a phase tracking signal corrects for sampling frequency offset errors. | 09-11-2008 |
| 20080279270 | HIGH SPEED DATA PACKET ACCESS MINIMUM MEAN SQUARED EQUALIZATION WITH DIRECT MATRIX INVERSION TRAINING - The present invention provides a equalizer processing module operable to cancel interference associated with received radio frequency (RF) burst(s). This equalizer processing module includes a first equalizer processing branch and an optional second equalizer processing branch. The first equalizer processing branch is operable to be trained by applying a recursive DMI process such as a Levison algorithm, based upon known training sequences and equalize the received RF burst. This results in soft samples or decisions which in turn may be converted to data bits. The soft samples are processed with a de-interleaver and channel decoder, where the combination is operable to produce a decoded frame of data bits from the soft samples. This allows interfering signals to be cancelled and more accurate processing of the received RF bursts to occur. | 11-13-2008 |
| 20080285639 | OFFSET CALIBRATION METHODS AND RADIO FREQUENCY DATA PATH CIRCUITS - An offset calibration method is provided. Two input terminals of an equalizer are switched to a common voltage at a first time point, wherein the equalizer generates a first equalized signal and a second equalized signal according to the common voltage. It is determined whether a first offset voltage is present in the equalizer according to the first and second equalized signals generated from the common voltage. If the first offset voltage is determined to be present in the equalizer, a first compensation voltage is provided to the equalizer. | 11-20-2008 |
| 20080304557 | SELF-CALIBRATING CONTINUOUS-TIME EQUALIZATION - Embodiments of the invention comprise a continuous-time equalizer for reducing ISI in data received from a communication channel, and methods and circuitry for tuning or calibrating that equalizer. Selected coefficients for a transfer function of the equalizer circuit are fixed, while other coefficients are tuned by an adaptive algorithm. The adaptive algorithm minimizes errors associated with the tunable coefficients based on one or more training signals sent by the transmitter and received by the equalizer circuit at the receiver. The training signals allow for a variety of error terms to be calculated, from which the tunable coefficients are updated so as to iteratively minimize the error terms and simultaneously tune the equalizer to more accurately compensate for the degrading effects of the channel. | 12-11-2008 |
| 20090110043 | Performing adaptive external equalization - In one embodiment, the present invention includes a method communicating control information for an external adaptive equalization process for a channel coupled between a transmitter and a receiver from an external agent. In this way, the external agent may control tap settings of an equalizer based on feedback information from the receiver responsive to a data pattern generated and transmitted by the transmitter. Other embodiments are described and claimed. | 04-30-2009 |
| 20090110044 | Method and Apparatus for Deciding a Channel Impulse Response - Method and apparatus for deciding a channel impulse response for an OFDM system are provided. First, a channel frequency response is generated by using a plurality of pilot tones of a signal. A channel impulse response is generated by applying the IFFT to the channel frequency response. A plurality of selected channel taps are derived by comparing a plurality of channel taps related to the channel impulse response with a reference threshold. Finally, the channel impulse response is generated by calculating channel impulse respose according to the selected channel taps. This method calculates the channel impulse response in time domain and frequency domain so that the calculation complexity can be reduced, and the system efficiency can be enhanced. | 04-30-2009 |
| 20090135895 | Self-calibrated adaptive equalization system and methods of performing the same - A self-calibrating, adaptive equalization system for generating an ideal digital signal is disclosed. The adaptive equalization system includes an equalizer and a high-gain buffer. The equalizer includes a first equalizer loop that feeds-back a control voltage to the equalizer and the high-gain buffer that includes a second equalizer loop that feeds-back a high-pass-to-low-pass filter ratio signal. Each of the first and second equalizer loops has a high-pass and a low-pass filter, rectifying circuits for each of the filters, and an integrating circuit that compares signal energy output from the rectifiers. The adaptive equalization system generates an ideal digital signal. | 05-28-2009 |
| 20090141787 | ADAPTIVE EQUALIZATION METHODS AND APPARATUS - A system includes a programmable transmitter device (e.g., a PLD) connected to a programmable receiver device (e.g., another PLD) via a transmission medium for transmitting a high-speed data signal from the transmitter to the receiver. During a test mode of operation a low-speed communication link between the transmitter and receiver allows those devices to work together to transmit test signals having known characteristics from the transmitter to the receiver via the transmission medium, to analyze the test signals as received by the receiver, and to adjust at least some aspect of the system (e.g., equalizer circuitry in the receiver) to at least partly compensate for losses in the test signals as received by the receiver. | 06-04-2009 |
| 20090161746 | RECEIVER ADJUSTMENT BETWEEN PILOT BURSTS - A receiver may train its equalizer using consecutive pilot bursts, divide the traffic between the consecutive pilot bursts into multiple sub-segments, and interpolate the trained equalizer coefficients to obtain the coefficients for equalizing one or more of the sub-segments. The receiver may also determine signal to interference and noise ratio (SINR) values based on each of the consecutive pilot bursts, and interpolate the SINR for decoding one or more of the sub-segments. The receiver may be an access terminal receiver operating in a code division multiple access (CDMA) cellular system. | 06-25-2009 |
| 20090161747 | NOISE PREDICTION-BASED SIGNAL DETECTION AND CROSS-TALK MITIGATION - In an exemplary embodiment, noise prediction-based data detection is described with respect to a SERDES (serializer/deserializer) backplane primary channel subject to inter-symbol interference (ISI) noise and added cross-talk noise from other channels. Noise prediction-based data detection combines an added error component from inter-symbol interference (ISI) noise and an added error component from cross-talk noise into an overall noise prediction error term and cancels effects of residual ISI and cross-talk for various components of the exemplary embodiment. | 06-25-2009 |
| 20090168862 | Methods and Apparatus for Detecting and Decoding Adaptive Equalization Training Frames - Methods and apparatus are provided for detecting and decoding adaptive equalization training frames (having a frame marker comprised of a string of binary ones and binary zeroes). Training frames are detected by shifting the received data; inserting at least one binary value at one end of the shifted received data to generate a modified version of the received data; applying a logic function to the received data and the modified version of the received data that identifies when corresponding bit positions have different values; and detecting the frame marker when an output of the logic function has a first binary value in an approximate middle of a string of a second binary value. The training frames are decoded using a distance between the approximate center of the frame maker and a predefined binary value in an output of the logic function. | 07-02-2009 |
| 20090175327 | EQUALIZERS FOR LAYERED MODULATED AND OTHER SIGNALS - A method and apparatus for equalizing digital data signals is disclosed. The method comprises the steps of demodulating and decoding an input signal having input data to produce a data output, remodulating the data output to produce a training sequence including an idealized input signal, wherein the training sequence is comprised of adjacent symbols in the input data, and generating equalizer parameters from the training sequence. The apparatus comprises a demodulator (for demodulating an input signal to produce a data output), a modulator communicatively coupled to the demodulator (for remodulating the data output to produce a training sequence including an idealized input signal wherein the training sequence is comprised of adjacent symbols in the input data), and a parameter generation module communicatively coupled to the modulator (for generating equalizer parameters from the training sequence). | 07-09-2009 |
| 20090185609 | EQUALIZER TEST CIRCUIT AND EQUALIZER TEST SIGNAL GENERATION CIRCUIT - A test circuit to test an equalizer is disclosed. Pseudo-random number data is generated by a pseudo-random number data generation unit. A weight coefficient is generated by a weight coefficient generation unit in order to set interference strength of intersymbol interference. In a pseudo-intersymbol interference data generation unit, pseudo-intersymbol interference is generated according to a bit sequence of the pseudo-random number data, and pseudo-intersymbol interference data is outputted. An amplitude of the pseudo-intersymbol interference data is changed according to the weight coefficient. A driver converts the pseudo-intersymbol interference data into a differential signal. A comparison unit compares the pseudo-random number data generated by the pseudo-random number data generation unit with output data obtained from the equalizer, when the differential signal outputted from the driver is inputted into the equalizer. A count unit counts the number of unmatched data detected by the comparison unit. | 07-23-2009 |
| 20090185610 | Joint Demodulation Using a Viterbi Equalizer Having an Adaptive Total Number of States - Systems and methods for performing joint demodulation using a Viterbi equalizer having an adaptive total number of states are disclosed. Generally, a method includes joint demodulating a desired signal and none or more interfering signals with a Viterbi equalizer having an adapative total number of states based on channel impulse response (CIR) coefficients associated with a desired signal ant the one or more interfering signals. | 07-23-2009 |
| 20090207898 | METHOD APPLIED TO AN EQUALIZER FOR REDUCING ISI AND RELATED ISI REDUCTION APPARATUS - A method applied to an equalizer includes receiving an input data-stream having a training sequence component with a first number of symbols and a data component with a second number of symbols, wherein the first number plus the second number equals a third number; when a symbol number is not greater than the first number, training the training sequence component to generate a first trained coefficient set; when the symbol number is between the first number and the third number, recycling the training sequence component to generate a recycled training sequence component, and training the recycled training sequence component to generate a second trained coefficient set; storing the input data-stream to generate a delayed input data-stream when the symbol number is not greater than the third number; and applying the second trained coefficient set to the equalizer when the symbol number is greater than the third number. | 08-20-2009 |
| 20090207899 | Equalizer training method using re-encoded bits and known training sequences - The present invention provides a multi-branch equalizer processing module operable to cancel interference associated with received radio frequency (RF) burst(s). This multi-branch equalizer processing module includes both a first equalizer processing branch and a second equalizer processing branch. The first equalizer processing branch is operable to be trained based upon known training sequences and equalize the received RF burst. This results in soft samples or decisions which in turn may be converted to data bits. The soft samples are processed with a de-interleaver and channel decoder, where the combination is operable to produce a decoded frame of data bits from the soft samples. A re-encoder may re-encode the decoded frame to produce re-encoded or at least partially re-encoded data bits. An interleaver then processes the at least partially re-encoded data bits to produce and at least partially re-encoded burst. The second equalizer processing branch uses the at least partially re-encoded data bits to train linear equalizer(s) within the second equalizer processing branch. A buffer may initially store the received RF burst(s), which are retrieved and equalized by the second equalizer processing branch once the linear equalizer(s) are trained. This results in alternate soft samples or decisions which in turn may be converted to alternate data bits. The alternate soft samples are processed with the de-interleaver and channel decoder, where the combination is operable to produce an alternate decoded frame of data bits from the alternate soft samples. This allows interfering signals to be cancelled and more accurate processing of the received RF bursts to occur. | 08-20-2009 |
| 20090213920 | METHOD AND APPARATUS FOR DETECTING HIGH-MOBILITY STATE OF MOBILE TERMINAL AND RELATED DEVICE - The invention provides a method of detecting high-mobility state of mobile terminal, comprising steps of: estimating a channel impulse response (CIR) based on received signal samples; performing channel equalization based on said received signal samples and the estimated channel impulse response; computing at least one characteristic value for a particular region of a relevant time slot based on the equalized signal samples; and deciding if said at least one characteristic value satisfies a predetermined condition that mobile terminal is in high-mobility state. The invention also provides a corresponding apparatus comprising: a channel estimator; a channel equalizer; computing means for computing at least one characteristic value for a particular region of a relevant time slot based on the equalized signal samples; and deciding means for deciding if said at least one characteristic value satisfies a predetermined condition of mobile terminal being in high-mobility state. | 08-27-2009 |
| 20090219982 | Selectively Disabling Interference Cancellation Based on Channel Dispersion Estimation - A channel dispersion estimation algorithm(s) may be implemented within a channel length estimation module of a multi-branch equalizer processing module that disables a branch of the multi-branch equalizer processing module when the channel length or channel delay spread associated with received radio frequency (RF) bursts exceeds a predetermined threshold. The channel dispersion estimation algorithm identifies when the radio frequency (RF) bursts have a channel length or channel delay spread that can affect receiver performance. The channel length estimation module may disable interference cancellation by a branch of the multi-branch equalizer processing module in response to such a channel length or channel delay spread. | 09-03-2009 |
| 20090252212 | METHOD AND APPARATUS FOR EQUALIZING A HIGH SPEED SERIAL DATA LINK - A method and apparatus for equalizing a reflection in a reflective high speed serial link. The method involves obtaining an amplitude and delay time of a compensating pulse that is transmitted in response to a pulse transmitted on the serial link. The apparatus comprises a programmable delay element and a driver stage configured to transmit a delayed and amplitude adjusted version of a pulse transmitted on the serial link. A method for equalizing a plurality of reflections in a reflective high speed serial link. The method involves obtaining an amplitude and delay time of a first compensating pulse and an amplitude and delay time of a second compensating pulse. The method further involves transmitting the first compensating and second compensating pulses in response to a pulse transmitted on the serial link. | 10-08-2009 |
| 20090252213 | Selectable-Tap Equalizer - A signaling circuit having a selectable-tap equalizer. The signaling circuit includes a buffer, a select circuit and an equalizing circuit. The buffer is used to store a plurality of data values that correspond to data signals transmitted on a signaling path during a first time interval. The select circuit is coupled to the buffer to select a subset of data values from the plurality of data values according to a select value. The equalizing circuit is coupled to receive the subset of data values from the select circuit and is adapted to adjust, according to the subset of data values, a signal level that corresponds to a data signal transmitted on the signaling path during a second time interval. | 10-08-2009 |
| 20090296799 | Channel identification, emulation, and frame synchronization for digital television signals - The present invention is related to channel identification, equalizer initialization, and framing synchronization of GB 20600-2006 digital television signals. In one embodiment, the present invention provides, in a communications receiver having an equalizer that processes GB 20600-2006 digital television signals that include payload data, a method that initializes the equalizer coefficients for processing the payload data comprising: identifying a channel estimate based on correlation techniques; producing known, mock received data and filtering the mock, received data through the channel estimate to produce mock filtered data; adjusting the equalizer coefficients with the mock received data or the mock filtered data to obtain an initial equalizer setting; and processing the payload data with the initial equalizer setting. | 12-03-2009 |
| 20100014573 | SEARCH ENGINE FOR A RECEIVE EQUALIZER - A search engine selects initial coefficients for a receive equalizer. The search engine may be incorporated into a communication receiver that includes a decision feedback equalizer and clock and data recovery circuit. Here, the search engine may initialize various adaptation loops that may control the operation of, for example, a decision feedback equalizer, a clock and data recovery circuit and a continuous time filter. The receiver may include an analog-to-digital converter that is used to generate soft decision data for some of the adaptation loops. | 01-21-2010 |
| 20100020860 | Methods And Apparatus For Joint Adaptation Of Transmitter Transversal Filter In Communication Devices - Methods and apparatus are provided for joint adaptation of filter values in two communicating devices, such as a link partner and a link device. The disclosed joint adaptation process initially adapts the filter coefficient values in a first of the two communicating devices until a predefined stopping criteria is satisfied. Thereafter, the filter coefficient values in a second of the two communicating devices are adapted once the predefined stopping criteria for the first communicating device is satisfied. The filter coefficient values can comprise coefficient values of a multi-tap filter. The predefined stopping criteria may determine, for example, whether the first of the two communicating devices is overequalized. The filter coefficient values can be determined by including a contribution of only certain cursor tap values of the channel impulse response. | 01-28-2010 |
| 20100020861 | DFE Margin Test Methods and Circuits that Decouple Sample and Feedback Timing - Described are methods and circuits for margin testing digital receivers. These methods and circuits prevent margins from collapsing in response to erroneously received data, and can thus be used in receivers that employ historical data to reduce intersymbol interference (ISI). Some embodiments allows feedback timing to be adjusted independent of the sample timing to measure the effects of some forms of phase misalignment and jitter. | 01-28-2010 |
| 20100054321 | Systems and Methods that Provide Frequency Domain Supplemental Training of the Time Domain Equalizer for DMT - Using a known or later developed time domain equalizer coefficient training algorithm, a least square solution for the time domain equalizer coefficients is taken at a starting point and iteratively improved on. In particular, the improvement is directed towards maximizing number of bits per frame loaded over the time domain equalizer coefficient choice. This can be accomplished by maximizing capacity directly rather than setting a goal to shorten the channel and hoping that the capacity will be maximized as a result. | 03-04-2010 |
| 20100080275 | TRAINING OF THE NON-UPDATED DECISION FEEDBACK EQUALIZER FOR A 8-VSB RECEIVER - A method for training of a non-updated decision feedback equalizer is provided. The method comprising the steps of: providing a sequence of frames adapted to be received by a receiver; provide a sequence of synchronization frames interposed between a predetermined number of frames; and using at least part of the sequence of synchronization frames to train a decision feedback equalizer (DFE), thereby speeding up system convergence or making system convergence possible. | 04-01-2010 |
| 20100091830 | EQUALIZER AND METHOD FOR CONFIGURING THE EQUALIZER - An equalizer includes a tapped delay line and an adder. The tapped delay line includes a plurality of taps cascaded to each other. The tapped delay line receives an input signal, a plurality of tap control signals, and a plurality of tap coefficients and generates a plurality of multiplied signals. The plurality of taps is divided into a plurality of groups. The adder is coupled to the tapped delay line for adding the plurality of multiplied signals up to generate an output signal. | 04-15-2010 |
| 20100128771 | COMMUNICATION APPARATUS, COMMUNICATION FRAME FORMAT, AND SIGNAL PROCESSING METHOD - A communication apparatus includes a signal detection section that detects received information from a signal received through wireless communication. The signal detection section includes: a wave detection section that receives a signal in which the received information is superimposed on a carrier signal and that analyzes variations in an envelope of the received signal to generate a wave-detection signal containing the received information; an equalization processing section that corrects the wave-detection signal to output a corrected wave-detection signal; a detection section that receives the corrected wave-detection signal to detect the received information; and a training data detection section that detects from the received signal a training-data-detection sync signal allowing detection of training data utilized to optimize equalization characteristics of the equalization processing section. The equalization processing section starts a training process, in which the training data contained in the received signal are utilized, on the basis of the sync signal. | 05-27-2010 |
| 20100135375 | TRANSMITTING/RECEIVING SYSTEM AND METHOD OF PROCESSING BROADCAST SIGNAL IN TRANSMITTING/RECEIVING SYSTEM - A receiving system and a method of processing broadcast signal are disclosed herein. The receiving system includes a signal receiving unit, a detector, and a channel equalizer. The signal receiving unit receives a broadcast signal including mobile service data and a data group including N number of training sequences. The detector detects N number of training sequences from the broadcast signal (wherein N≧ | 06-03-2010 |
| 20100177815 | SYSTEMS AND METHODS FOR PERFORMING COMBINED EQUALIZATION IN COMMUNICATION SYSTEMS - A system is described for performing combined equalization. The system comprises a time domain equalizer (TEQ) configured to receive a signal and shorten a CIR (channel impulse response) of the received signal, a Fast Fourier Transform (FFT) module for demodulating the received signal, and an equalization block for reducing inter-carrier interference (ICI) and inter-symbol interference (ISI). The equalization block comprises at least one of: a feed forward equalizer and a feed back equalizer. The system further comprises a slicer circuit configured to generate a hard-limited decision for a symbol corresponding to the received signal. | 07-15-2010 |
| 20100189169 | 16-STATE ADAPTIVE NOISE PREDICTIVE MAXIMUM-LIKELIHOOD DETECTION SYSTEM - A 16-State adaptive NPML detector is provided for a tape drive which addresses weaknesses of a conventional fixed, 8-state EPR4 detector. Rather than having a fixed target channel, the detector is programmable to allow a range of target channels and can support “classical” partial response channels such as PR4 or EPR4 by programming predictor or whitening filter coefficients. In one embodiment, two filter coefficients may be set via XREG inputs or dynamically determined through the use of an LMS algorithm allowing the detector to adapt the predictor coefficients as data is being read. Another embodiment provides a detector for an EPR4 target in which the whitening filter has one coefficient. Components of the detection system include the detector itself, an LMS engine, a coefficient engine and a noise predictive or whitening filter. Coefficients from the LMS engine may be loaded or stored dynamically based upon conditions in the tape drive. | 07-29-2010 |
| 20100189170 | METHOD AND APPARATUS FOR DIGITALLY EQUALIZING A SIGNAL IN A DISTRIBUTED ANTENNA SYSTEM - Systems and methods for digitally equalizing a signal in a distributed antenna system are provided. In one embodiment, a signal processing device within a distributed antenna system comprises a signal path within a signal processing board, the signal path having an uncompensated distortion function of G(ω) with a system response represented by y(n); and a compensator coupled to the signal path, the compensator having a finite impulse response (FIR) filter with an impulse response function represented by H(ω), the compensator having an FIR filter parameter vector {right arrow over (h)} determined from an estimated system response y(n) of the signal path to an input comb signal x(n), wherein y(n) is estimated from interpolated measured output responses of the signal path to a plurality of frequency sweep signal test inputs. | 07-29-2010 |
| 20100215090 | Equalizer for AM In-Band On-Channel Radio Receivers - A method is provided for equalizing OFDM symbol vectors received on AM in-band on-channel radio signal including a main carrier and first and second BPSK modulated subcarriers. The method comprises the steps of: computing a BPSK magnitude signal; filtering the BPSK magnitude signal; filtering complex samples received on the main carrier; using the filtered BPSK magnitude signal and the filtered complex samples received on the main carrier to compute a plurality of flat fade equalization coefficients; and multiplying the OFDM symbol vectors by the flat fade equalization coefficients. A receiver that includes an equalizer, which operates in accordance with the method is also provided. | 08-26-2010 |
| 20100226422 | Precoder Construction And Equalization - Apparatus and methods are provided to construct parameters associated with a precoder to a channel. Embodiments include apparatus and methods to apply a maximum a posteriori probability (MAP) equalization using offsets of signals introduced at a transmit end of a channel. Embodiments include apparatus and methods to construct a channel precoder based on using approximation of channel responses for a range of channel lengths. | 09-09-2010 |
| 20100290514 | Systems and Methods that Provide Frequency Domain Supplemental Training of the Time Domain Equalizer for DMT - Using a known or later developed time domain equalizer coefficient training algorithm, a least square solution for the time domain equalizer coefficients is taken at a starting point and iteratively improved on. In particular, the improvement is directed towards maximizing number of bits per frame loaded over the time domain equalizer coefficient choice. This can be accomplished by maximizing capacity directly rather than setting a goal to shorten the channel and hoping that the capacity will be maximized as a result. | 11-18-2010 |
| 20100329322 | Real-Time Eye Monitor for Statistical Filter Parameter Calibration - In described embodiments, filter parameters for a filter applied to a signal in, for example, a Serializer/De-serializer (SerDes) receiver and/or transmitter are generated based on real-time monitoring of a data eye. The real-time eye monitor monitors data eye characteristics of the signal present in a data path, the data path applying the filter to the signal. The eye monitor generates eye statistics from the monitored data eye characteristics and an adaptive controller generates a set of parameters for the filter of the data path for statistical calibration of the data eye, wherein the eye monitor continuously monitors the data eye and the adaptive controller continuously generates the set of parameters based on the eye statistics. | 12-30-2010 |
| 20110026576 | Adaptive interference cancellation algorithm using speech mode dependent thresholds - Adaptive interference cancellation algorithm using speech mode dependent thresholds. A method of processing radio frequency (RF) bursts dependent on a speech mode associated with data contained within the RF burst is presented. Different voice modes, full rate, half rate, and adaptive multi-channel rates each may require different signal to noise ratio (SNR) conditions in order to be successfully processed. To improve the equalization, the SNR associated with the burst is estimated. Based on the SNR or other related conditions, a decision can be made as to whether or not an interference cancellation burst process should be implemented. For example, any one or more of SNR of the signal, a measure of colored noise within the signal, an indication whether the signal being noise limited or interference limited, and a channel profile of the signal may indicate the presence of interference requiring the cancellation of such interference. | 02-03-2011 |
| 20110255586 | SYSTEMS AND METHODS FOR FREQUENCY DOMAIN REALIZATION OF NON-INTEGER FRACTIONALLY SPACED TIME DOMAIN EQUALIZATION - Various systems and methods are described for performing fractionally spaced time domain equalization (TEQ). One embodiment is a method implemented in a communication system for training a fractionally spaced time domain equalizer (TEQ). The method comprises performing an initialization phase, averaging a received signal in the system to reduce effects of noise in a channel, determining a channel estimate, and aligning an ideal reference signal with the received signal. The method further comprises updating a target response filter according to a non-integer multiple of a base sampling rate, determining an adaptation error based on useful information both inside and outside a Nyquist band of the TEQ, and updating the TEQ according to the adaptation error. | 10-20-2011 |
| 20110310950 | COAXIAL NETWORK COMMUNICATION NODE AND METHODS FOR COMMUNICATING WITHIN A MoCA NETWORK WITH REDUCED-LENGTH CYCLIC PREFIXES - A coaxial network communication node receives multimedia content with one or more other nodes in a Multimedia over Coax Alliance (MoCA®) coaxial network. The node determines a delay-spread of a coaxial channel based on a probe received from a transmitting node during a link-maintenance operation (LMO) cycle. The probe is stored and reused during the LMO until the channel-shortening TEQ filter converges. The node configures a channel-shortening time-domain equalizer (TEQ) filter to effectively shorten the channel and instructs the transmitting node to shorten a length of a cyclic prefix for subsequent packet-based transmissions. | 12-22-2011 |
| 20120014428 | METHODS AND SYSTEMS FOR INITIAL FCH PROCESSING - Methods and apparatus for initially decoding a frame control header (FCH) in an orthogonal frequency-division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) system in an effort to accurately determine the downlink frame prefix (DLFP) such that the remainder of an OFDM/A frame may be properly decoded are provided. Used, for example, when boosting factors applied in the transmitter to various elements of the OFDM/A frame and/or available pilots for the FCH are unknown, such methods may utilize a preamble channel estimate, the FCH pilots, or a combination thereof. | 01-19-2012 |
| 20120020404 | CLOCK-SYNCHRONIZED METHOD FOR UNIVERSAL SERIAL BUS (USB) - A clock-synchronized method for universal serial bus (USB) is described. The method includes the following steps of: (a) a transmitter sends a periodic signal to a host unit during a first time interval; (b) the host unit transmits a first equalization training sequence signal to a receiver during a second time interval to train the receiver and the transmitter continuously sends the periodic signal to the host unit; (c) a clock and data recovery device extracts the first equalization training sequence signal during the second time interval to generate a extracted clock signal and a data signal; and (d) the transmitter sends a second equalization training sequence signal to the host unit based on the extracted clock signal during the third time interval to train the host unit and the receiver and the transmitter commonly utilize the extracted clock signal as a reference clock. | 01-26-2012 |
| 20120027071 | RECEIVER AND METHOD FOR EQUALIZING RECEIVED SIGNAL - A receiver includes a discrete Fourier transform unit, a frequency-domain equalizer, an inverse discrete Fourier transform unit, a time-domain equalizer and an output circuit. The discrete Fourier transform unit is utilized for performing a discrete Fourier transform operation upon a received signal to generate a frequency-domain signal. The frequency-domain equalizer is utilized for equalizing the frequency-domain signal to generate an equalized frequency-domain signal. The inverse discrete Fourier transform unit is utilized for performing an inverse discrete Fourier transform operation upon the equalized frequency-domain signal to generate a first equalized time-domain signal. The time-domain equalizer is utilized for equalizing the received signal to generate a second equalized time-domain signal. The output circuit is utilized for generating a third equalized time-domain signal according to the first equalized time-domain signal and the second equalized time-domain signal. | 02-02-2012 |
| 20120063503 | Methods and apparatus for orthogonal modulated signals - Methods and corresponding systems for providing and demodulating an orthogonal modulated signal where demodulation includes separating a sampled orthogonal modulated signal into in phase and quadrature samples, deriving first and second equalizer coefficients based on corresponding in phase and quadrature samples and further, respectively, based on a first and second training sequence, programming a first plurality of equalizer filters with the first equalizer coefficients and a second plurality of equalizer filters with the second equalizer coefficients; and processing, after programming with first and second coefficients, the in phase samples and the quadrature samples through a first and second plurality of equalizer filters to provide demodulated symbols. | 03-15-2012 |
| 20120106615 | MULTIDIMENSIONAL ADAPTIVELY TRAINED EQUALIZATION - An embodiment of the invention is a technique to equalize received samples. An equalizer equalizes a multidimensional signal transmitted over a communication channel and having a dimensionality of four or higher. The equalizer is adaptively trained based on an optimality criterion. | 05-03-2012 |
| 20120170637 | METHOD AND APPARATUS FOR REDUCING POWER CONSUMPTION OF COMMUNICATION DEVICE - A communication device is disclosed including: an analog-to-digital converter (ADC) for converting an analog input signal into a digital input signal; an equalizer module coupled with the ADC for processing the digital input signal to generate an equalized signal; a data slicer coupled with the equalizer module for generating an output signal based on the equalized signal; and a control unit coupled with the equalizer module and the data slicer; wherein the control unit or the equalizer module preserves at least one signal equalizing parameter of the equalizer module before the equalizer module enters power saving mode, and the equalizer module loads the at least one signal equalizing parameter to operate when the communication device receives a predetermined control signal. | 07-05-2012 |
| 20120257667 | Methods And Apparatus For Weighted Equalization - Systems and techniques for equalization of a response of a receiver. In one embodiment, a response of a device to a known signal is measured to generate a measured signal. A processor is operated to apply an initial weighting to the measured signal and the known signal. The processor is operated to iteratively perform the operations of constructing an equalizer based on the weighted signals, testing the performance of the equalizer on the measured signal, and adjusting weighting applied to the measured signal and the known signal, until the performance of the equalizer on the measured signal meets a predetermined criterion. | 10-11-2012 |
| 20130003816 | METHOD AND APPARATUS FOR CHANNEL AND NOISE ESTIMATION - Techniques for performing channel and noise estimation for a MIMO transmission sent from multiple transmit antennas to multiple receive antennas are described. Samples are obtained from the receive antennas. For a first scheme, channel estimates are derived by correlating the samples with at least one pilot sequence, and signal, noise and interference statistics are also estimated based on the samples. For a second scheme, total received energy as well as signal and interference energy are estimated based on the samples. Noise is then estimated based on the estimated total received energy and the estimated signal and interference energy. For a third scheme, signal and on-time interference statistics are estimated based on the samples. Noise and multipath interference statistics are also estimated based on the samples. Signal, noise and interference statistics are then estimated based on the estimated signal and on-time interference statistics and the estimated noise and multipath interference statistics. | 01-03-2013 |
| 20130010854 | TRANSMITTER EQUALIZER OPTIMIZATION - A transmitter includes an equalizer for conditioning a data signal in response to a first and a second equalizer setting. The first and second equalizer settings are both associated with a selected point on a two-dimensional search grid. The search grid includes a first equalizer setting and a second equalizer setting for each point on the search grid. The transmitter transmits a data signal across a first channel medium using settings associated with a selected point on the search grid. A receiver analyzes the received signal from the transmitter to determine a signal quality metric. The search grid is used to select settings from neighboring points to produce signals that are evaluated to produce signal quality metrics. The results of the evaluations are used to efficiently search the search grid for optimum equalizer settings for the transmitter. | 01-10-2013 |
| 20130064280 | DIGITAL BROADCASTING TRANSMITTER, DIGITAL BROADCASTING RECEIVER, AND STREAM CONFIGURATION AND METHOD FOR PROCESSING SAME - Provided are a digital broadcast transmitter, a digital broadcast receiver, a stream-processing method for the digital broadcasting transmitter, and a stream-processing method for the digital broadcast receiver. The stream-processing method for the digital broadcasting transmitter includes: configuring a stream in which slots including a plurality of blocks are continuously disposed; and encoding and interleaving the stream to be output as a transport stream, wherein the configuring the stream includes, if slots of a block extension mode 00 are continuously placed, connecting known data placed in predetermined locations of adjacent slots to each other in order to generate a long training sequence. | 03-14-2013 |
| 20130070833 | ADVANCED JOINT DETECTION IN A TD-SCDMA SYSTEM - A communication system is provided that includes a composite transfer module that receives an input signal and performs one or more selective operations defined by a first transfer function on the input signal. The composite transfer module outputs a first signal. A joint detection module receives the first signal and performs joint detection on the first signal. The joint detection module utilizes channel estimation information of the first transfer function so as to allow the joint detection module to perform joint detection with an oversampling rate of 2× or higher. | 03-21-2013 |
| 20130156086 | METHODS AND APPARATUS FOR DETECTING AND DECODING ADAPTIVE EQUALIZATION TRAINING FRAMES - Methods and apparatus are provided for detecting and decoding adaptive equalization training frames (having a frame marker comprised of a string of binary ones and binary zeroes). Training frames are detected by shifting the received data; inserting at least one binary value at one end of the shifted received data to generate a modified version of the received data; applying a logic function to the received data and the modified version of the received data that identifies when corresponding bit positions have different values; and detecting the frame marker when an output of the logic function has a first binary value in an approximate middle of a string of a second binary value. The training frames are decoded using a distance between the approximate center of the frame marker and a predefined binary value in an output of the logic function. | 06-20-2013 |
| 20130170538 | EQUALIZER RECEIVER AND OPERATING METHOD THEREOF IN WIRELESS COMMUNICATION SYSTEM - An equalizer-based receiver and an operating method thereof in a wireless communication system are provided. The equalizer-based receiver includes a reception multi-path detector, a controller, and an equalize receiver. The reception multi-path detector groups reception signals according to a predetermined reference to classify the reception signals into a plurality of delay clusters, and estimates a position of the plurality of delay clusters. The controller determines whether the plurality of delay clusters exist within a predetermined threshold range based on a result of the estimated position, and controls an operation mode of the equalizer-based receiver depending on a result of the determination. The equalize receiver performs one of a mode for removing an interference between the plurality of delay clusters and a mode for applying a diversity technique to a delay cluster under control of the controller. | 07-04-2013 |
| 20130195166 | Robust Frequency-Domain Equalization in Communications Receivers - MMSE equalization in the frequency domain is emulated by applying intermediate weights on a per-frequency-bin basis and re-scaling each bin output to recover proper MMSE scaling. Time-domain samples of a received signal are transformed into a frequency-domain representation of the received signal. A frequency-domain representation of a channel response for the radio channel is calculated, and a frequency-domain representation of impairments to the desired signal is generated, the frequency-domain representation of the impairments comprising an impairment covariance matrix for each of the frequency bins. A scaling factor for each of frequency bins is calculated, based on a bin-specific signal-quality estimate for each bin, and an equalized frequency-domain sample for each of the frequency bins is computed, as a function of the scaling factors, the frequency-domain representation of the channel response, and the generated frequency-domain representation of impairments. The equalized frequency-domain samples are transformed into an equalized time-domain sample sequence. | 08-01-2013 |
| 20130195167 | System and Method for Non-Interleaved Signal Field - Efficient decoding in IEEE 802.11ah networks can be achieved by transmitting the signal (SIG) preamble field without interleaving bits within the SIG field. This may allow channel equalization and decoding steps to be performed contemporaneously upon reception of the frame, which allows for the implementation of non-linear channel equalization techniques (e.g., maximum likelihood (ML) equalization, etc. | 08-01-2013 |
| 20130223504 | Estimation of Low-Amplitude Echoes in a Received Communication Signal - A system and method for identifying minor echoes present in an input signal in the situation where a set of major echoes has already been identified from the input signal. The method includes: computing a spectrum F corresponding to a sum of the major echoes; computing a weighted power spectrum S | 08-29-2013 |
| 20130230089 | SELF-CALIBRATING CONTINUOUS-TIME EQUALIZATION - Embodiments of the invention comprise a continuous-time equalizer for reducing ISI in data received from a communication channel, and methods and circuitry for tuning or calibrating that equalizer. Selected coefficients for a transfer function of the equalizer circuit are fixed, while other coefficients are tuned by an adaptive algorithm. The adaptive algorithm minimizes errors associated with the tunable coefficients based on one or more training signals sent by the transmitter and received by the equalizer circuit at the receiver. The training signals allow for a variety of error terms to be calculated, from which the tunable coefficients are updated so as to iteratively minimize the error terms and simultaneously tune the equalizer to more accurately compensate for the degrading effects of the channel. | 09-05-2013 |
| 20130272364 | LOW-COMPLEXITY CHANNEL NOISE REDUCTION METHOD AND APPARATUS FOR MULTI-CARRIER MODE IN WIRELESS LANS - Low-complexity channel noise reduction method and apparatus for multi-carrier mode in wireless LANs are disclosed. The method selects an optimal frequency domain channel impulse response by using a known long training sequence and a highly protected signaling sequence of the multi-carrier mode frame structure to ensure the receiver to have a good operation threshold in different time-delay spread environments at the cost of a low complexity. Instead of detecting time domain channel responses, the method directly performs noise reduction to a noise-containing frequency domain channel by using preset Wiener filtering coefficients to obtain multiple frequency domain channel responses, among which there must be a relatively optimal frequency domain channel response. The relatively optimal frequency domain channel response can be selected by using the highly protected signaling sequence to calculate the signaling frequency domain channel. | 10-17-2013 |
| 20140079110 | EFFICIENT EQUALIZER COEFFICIENT COMPUTATION - An equalization parameter analyzer includes a parameter section configured to acquire at least one current parameter for a wireless receiver and an analyzer section configured to compare the at least one current parameter with at least one corresponding previous parameter. Additionally, the equalization parameter analyzer also includes a coefficients section configured to initiate a generation of new equalizer coefficients in the wireless receiver based on a change between the at least one current and corresponding previous parameters that exceeds a predefined threshold. A method of equalization coefficients generation is also provided. | 03-20-2014 |
| 20140140386 | TRACE CANCELLER WITH EQUALIZER ADJUSTED FOR TRACE LENGTH DRIVING VARIABLE-GAIN AMPLIFIER WITH AUTOMATIC GAIN CONTROL LOOP - Distortions of both amplitude and phase along a transmission line are compensated for by a trace canceller inserted between a transmitter and a receiver. The trace canceller has an equalizer that compensates for a trace length between the transmitter and the trace canceller. A variable gain amplifier between the equalizer and an output buffer has its gain controlled by an automatic gain control circuit that compares low-frequency swings of the input and output of the trace canceller. The gain of the variable gain amplifier is reduced to prevent the output buffer from saturating and clipping peak voltages on its output. Thus both the variable gain amplifier and the output buffer remain in the linear region. Training pulses from the transmitter are passed through the trace canceller without clipping of peak voltages, allowing the transmitter and receiver to adjust transmission parameters to best match the transmission line. | 05-22-2014 |
| 20140177695 | MULTIPASS APPROACH FOR PERFORMING CHANNEL EQUALIZATION TRAINING - A method comprises performing a first pass test over a plurality of sets of equalization coefficients to filter the plurality of sets of equalization coefficients to produce one or more filtered sets of equalization coefficients. Each filtered set of equalization coefficients meets a first predetermined threshold. The method also comprises performing a second pass test over the one or more filtered sets of equalization coefficients to determine a final set of equalization coefficients that meets a second predetermined threshold. The second pass test produces more accurate results than the first pass test. | 06-26-2014 |
| 20140233627 | Adaptive Equalization Using Correlation of Edge Samples with Data Patterns - An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal. | 08-21-2014 |
| 20140241411 | System and Method for Link Training of a Backplane Physical Layer Device Operating in Simplex Mode - A system and method for link training of a backplane physical layer device operating in simplex mode. In one embodiment of the present invention, a backplane training system includes a backplane device coupled to a first end of a backplane and at least one retimer device at a second end of the backplane. During a training process, a receiving device is configured to forward a training frame (e.g., DME frame) to a second device for use by a transmitter in the second device. | 08-28-2014 |
| 20140269880 | COMMUNICATION SYSTEM AND METHOD USING SUBSPACE INTERFERENCE CANCELLATION - A receiver performs interference mitigation under blind or semi-blind conditions using diversity present in the signal of interest or in the interferer. A first path interference mitigation procedure extracts training information from received signals, performs interference mitigation on the training information and estimates the channel. The second path interference mitigation procedure uses data extracted from the received signal and the channel estimate to perform interference mitigation. Each interference mitigation process can take the form of a lossy compression followed by decompression. | 09-18-2014 |
| 20140269881 | Adaptive Backchannel Equalization - Techniques for adaptive backchannel equalization. A total equalization value is determined over a preselected training period. A total balance equalization value is determined over the preselected training period. A transmitter equalization coefficient is determined based on the total equalization value and the total balance equalization value. Data is transmitted over a serial link using the transmitter equalization coefficient. | 09-18-2014 |
| 20150110164 | OFDM PRE-EQUALIZING - For example in case of an OFDM multicarrier transmission system the transmission characteristics of subcarriers of a multicarrier transmission system using a plurality of antenna elements ( | 04-23-2015 |
| 20150131708 | Backchannel Communications For Initialization of High-Speed Networks - One embodiment provides a network controller. The network controller includes a modulation module. The modulation module includes a high rate (HR) bit sequence generator configured to generate a first high rate bit sequence, encoder circuitry configured to encode a first low rate bit stream, the first low rate bit stream comprising backchannel information, and modulation circuitry configured to modulate the encoded first low rate bit stream onto the first high rate bit sequence. The network controller further includes transmit circuitry configured to transmit the modulated first HR bit sequence to a link partner during a link initialization period. | 05-14-2015 |
| 20150349988 | SELECTING FLOATING TAP POSITIONS IN A FLOATING TAP EQUALIZER - In one embodiment, an apparatus has an equalizer, a tap position locator, and a tap weight updater. The equalizer has a plurality of floating taps. The tap position locator generates metrics for a set of possible tap positions of the equalizer. Each possible tap position corresponds to a different tap weight, and the metrics are generated without updating the tap weights for all of the possible tap positions in the set. Further, the tap position locator selects a subset of possible tap positions from the set based on the metrics. The tap weight updater updates a subset of the tap weights corresponding to the selected subset of possible tap positions, and applies the updated subset of tap weights to the plurality of floating taps. | 12-03-2015 |
| 20160149731 | TRANSMISSION DEVICE WITH CHANNEL EQUALIZATION AND CONTROL AND METHODS FOR USE THEREWITH - Aspects of the subject disclosure may include, for example, a transmission device that includes at least one transceiver configured to modulate data to generate a plurality of first electromagnetic waves in accordance with channel control parameters. A plurality of couplers are configured to couple at least a portion of the plurality of first electromagnetic waves to a transmission medium, wherein the plurality of couplers generate a plurality of second electromagnetic waves that propagate along the outer surface of the transmission medium. A training controller is configured to generate the channel control parameters based on channel state information received from at least one remote transmission device. Other embodiments are disclosed. | 05-26-2016 |
| 20220140866 | WIRELESS COMMUNICATION SYSTEM, WIRELESS COMMUNICATION METHOD, TRANSMITTING STATION DEVICE AND RECEIVING STATION DEVICE - A transmitting station apparatus includes a training signal generation unit, a transmission end linear equalization unit configured to equalize data signals by a transmission end transfer function, and a transmitting station communication unit configured to transmit a training signal or a plurality of data signals and receive information of the transmission end transfer function from a receiving station apparatus. The receiving station apparatus includes a communication path estimation unit configured to estimate a communication path response from the training signal, a reception end coefficient calculation unit configured to calculate the transmission end transfer function with an adjugate matrix of a transfer function matrix H of the communication path response as a transfer function and a reception end transfer function with an inverse of a determinant of the transfer function matrix H as a transfer function, and a reception end linear equalization unit configured to equalize reception signals by using the reception end transfer function. The reception end linear equalization unit determines whether the determinant of the transfer function matrix H is a minimum phase, performs a forward direction equalization in a case of the minimum phase, and performs an inverse direction equalization in a case of a non-minimum phase. | 05-05-2022 |
