Patent application number | Description | Published |
20090170452 | Integrated RF-IF converter - A frequency conversion apparatus includes a frequency generation circuit, which is based on a first semiconductor material having a first elemental composition and is coupled to generate one or more Local Oscillator (LO) signals. The apparatus further includes a conversion circuit, which is based on a second semiconductor material having a second elemental composition different from the first elemental composition. The conversion circuit is coupled to accept an input signal in a first frequency range and to convert the input signal to an output signal in a second frequency range by mixing the input signal with the one or more LO signals. | 07-02-2009 |
20100177228 | NARROW BANDWITH ILLUMINATION IMAGE PROCESSING SYSTEM AND METHOD - A low power color image capturing system having a power source, the system comprising: a narrow bandwidth illuminator adapted to provide illumination having a peak intensity defining a narrow bandwidth; an image capturing device adapted to capture a raw image from an object illuminated by the narrow bandwidth illuminator; and a processor adapted to control the system and having an algorithm operatable upon the raw image to provide a modified image; wherein the modified image has enhanced color intensities over substantially all visible wavelengths. | 07-15-2010 |
20100177762 | ROBUST CHANNEL ALLOCATION METHOD FOR RF COMMUNICATION SYSTEMS - A method of allocating channels in a PTMP (point-to-multi-point) system having a master and a plurality of nodes comprising the steps of: transmission by the master to the nodes of a synch beacon, the sync beacon having a first frequency and a substantially fixed time period between successive sync beacon transmissions; dividing the time period into a slotted time and an unslotted time; allocating a plurality of slots in the slotted time for RF activity of the nodes that have resolved the sync beacon; and identifying the unslotted time for unallocated RF activity of the nodes that have not resolved the sync beacon. | 07-15-2010 |
20130343446 | HIGHLY-SPECTRALLY-EFFICIENT RECEPTION USING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING - Circuitry for use in a receiver may comprise: a front-end circuit operable to receive an orthogonal frequency division multiplexing (OFDM) symbol on a first number of physical subcarriers. The circuitry may comprise a decoding circuit operable to decode the OFDM symbol using an inter-carrier interference (ICI) model, the decoding resulting in a determination of a sequence of symbols, comprising a second number of symbols, that most-likely correspond to the received OFDM symbol, where the second number is greater than the first number. The sequence of symbols may comprise N-QAM symbols, N being an integer. The ISCI model may be based, at least in part, on non-linearity experienced by the OFDM symbol during transmission by a transmitter, propagation over a channel, and/or reception by the receiver. The ISCI model may be based, at least in part, on phase-noise introduced to the OFDM symbol during transmission by a transmitter, propagation over a channel, and/or reception by the receiver. | 12-26-2013 |
20130343473 | Highly-Spectrally-Efficient Transmission Using Orthogonal Frequency Division Multiplexing - A transmitter may map, using a selected modulation constellation, each of C′ bit sequences to a respective one of C′ symbols, where C′ is a number greater than one. The transmitter may process the C′ symbols to generate C′ inter-carrier correlated virtual subcarrier values. The transmitter may decimate the C′ virtual subcarrier values down to C physical subcarrier values, C being a number less than C′. The transmitter may transmit the C physical subcarrier values on C orthogonal frequency division multiplexed (OFDM) subcarriers. The modulation constellation may be an N-QAM constellation, where N is an integer. The processing may comprise filtering the C′ symbols using an array of C′ filter tap coefficients. The filtering may comprise cyclic filtering. The filtering may comprise multiplication by a circulant matrix populated with the C′ filter tap coefficients. | 12-26-2013 |
20130343476 | JOINT SEQUENCE ESTIMATION OF SYMBOL AND PHASE WITH HIGH TOLERANCE OF NONLINEARITY - A method and system for a sequence estimation in a receiver, such as for use when receiving a sample of a received inter-symbol correlated (ISC) signal corresponding to a transmitted vector of L symbols, with L being a integer greater than 1, and with symbol L being a most-recent symbol and symbol 1 being least recent symbol of the vector. A plurality of candidate vectors may be generated, wherein element L-m of each candidate vector holding one of a plurality of possible values of the symbol L-m, with m is an integer greater than or equal to 1, and elements L-m+1 through L of each candidate vectors holding determined filler values. A plurality of metrics may be generated based on the plurality of candidate vectors, and based on the generated plurality of metrics, a best one of the possible values of the symbol L-m may be selected. | 12-26-2013 |
20130343480 | Multi-Mode Orthogonal Frequency Division Multiplexing Transmitter for Highly-Spectrally-Efficient Communications - A transmitter may comprise a symbol mapper circuit and operate in at least two modes. In a first mode, the number of symbols output by the mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter may be greater than the number of data-carrying subcarriers used to transmit the OFDM symbol. In a second mode, the number of symbols output by said mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter is less than or equal to the number of data-carrying subcarriers used to transmit said OFDM symbol. The symbols output by the symbol mapper circuit may be N-QAM symbols. While the circuitry operates in the first mode, the symbols output by the mapper may be converted to physical subcarrier values via filtering and decimation prior to being input to an IFFT circuit. | 12-26-2013 |
20130343485 | Multi-Mode Transmitter for Highly-Spectrally-Efficient Communications - A transmitter may comprise a symbol mapping circuit that is configurable to operate in at least two configurations, wherein a first of the configurations of the symbol mapping circuit uses a first symbol constellation and a second of the configurations of the symbol mapping circuit uses a second symbol constellation. The transmitter may also comprise a pulse shaping circuit that is configurable to operate in at least two configurations, wherein a first of the configurations of the pulse shaping circuit uses a first set of filter taps and a second of the configurations of the pulse shaping circuit uses a second set of filter taps. The first set of filter taps may correspond to a root raised cosine (RRC) filter and the second set of filter taps corresponds to a partial response filter. | 12-26-2013 |
20130343487 | Multi-Mode Receiver for Highly-Spectrally-Efficient Communications - A receiver may be dynamically configurable, during run-time, into a plurality of modes of operation. In a first mode of operation the receiver may demodulate received signals having relative low inter-symbol correlation using a near zero ISI filter and symbol slicing. In a second mode of operation the receiver may demodulate received signals having relatively high inter-symbol correlation using an input filter configured to achieve a desired total partial response and a sequence estimation algorithm. | 12-26-2013 |
20130343491 | MULTI-MODE ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING RECEIVER FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - A receiver may comprise a sequence estimation circuit and operate in at least two modes. In a first mode, the sequence estimation circuit may process OFDM symbols received on a first number of data-carrying subcarriers to recover a number of mapped symbols per OFDM symbol that is greater than the first number. In a second mode, the sequence estimation circuit may process OFDM symbols received on a second number of data-carrying subcarriers to recover a number of mapped symbols per OFDM symbol that is equal to the second number. The second number may be equal to or different from the first number. While the receiver operates in the first mode, the sequence estimation circuit may be operable to generate candidate vectors and process the candidate vectors using a controlled ISCI model to generate reconstructed physical subcarrier values. | 12-26-2013 |
20130343496 | REDUCED STATE SEQUENCE ESTIMATION WITH SOFT DECISION OUTPUTS - A receiver may be operable to receive an inter-symbol correlated (ISC) signal, and generate a plurality of soft decisions as to information carried in the ISC signal. The soft decisions may be generated using a reduced-state sequence estimation (RSSE) process. The RSSE process may be such that the number of symbol survivors retained after each iteration of the RSSE process is less than the maximum likelihood state space. The plurality of soft decisions may comprise a plurality of log likelihood ratios (LLRs). Each of the plurality of LLRs may correspond to a respective one of a plurality of subwords of a forward error correction (FEC) codeword. | 12-26-2013 |
20140003483 | Highly-Spectrally-Efficient Receiver | 01-02-2014 |
20140036986 | COARSE PHASE ESTIMATION FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - Methods and systems are provided for coarse phase estimation for highly-spectrally efficient communications. An example method may include, equalizing, in a receiver, a received inter-symbol correlated (ISC) signal to generate an equalized ISC signal. A phase adjustment signal may be generated based on an ISC feedback signal. The ISC feedback signal may be generated using a sequence estimation process and a non-linearity model. A phase of the equalized ISC signal may be adjusted using the generated phase adjustment signal, to generate a phase adjusted partial response signal. The phase adjustment signal may be generated based on a phase difference between the equalized ISC signal and the partial response feedback signal. | 02-06-2014 |
20140098907 | TIMING PILOT GENERATION FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - Methods and systems are provided for timing synchronization for reception of highly-spectrally efficient communications. An example method may include, mapping, in a transmitter, a plurality of transmit bits to a plurality of symbols at a symbol rate that is based on an oscillator signal. The plurality of symbols may be processed via a filter. The processing may result in an inter-symbol correlated (ISC) signal. The oscillator signal may be frequency divided to generate one or more pilot signals having a frequency that is a sub-harmonic of a frequency of the oscillator signal. The pilot signal may be injected into the ISC signal. The injecting may result in an ISC signal with timing carrier. The ISC signal with timing carrier may be transmitted. Gain of the one or more pilot signals may be adjusted based on a spectral mask value associated with the transmitting. | 04-10-2014 |
20140098915 | ADAPTIVE NON-LINEAR MODEL FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - A receiver may be operable to generate estimates of transmitted symbols using a sequence estimation process that may incorporate a non-linear model. The non-linear model may be adapted by the receiver based on particular communication information that may be indicative of non-linearity experienced by the transmitted symbols. The receiver may generate a reconstructed signal from the estimates of the transmitted symbols. The receiver may adapt the non-linear model based on values of an error signal generated from the reconstructed signal, and the values of the error signal may be generated from a portion of the generated estimates that may correspond to known symbols and/or information symbols. The values of the error signal corresponding to the known symbols may be given more weight in an adaptation algorithm, and the values of the error signal corresponding to the information symbols may be given less weight in the adaptation algorithm. | 04-10-2014 |
20140105267 | Signal Reception Using Non-Linearity-Compensated, Partial Response Feedback - A receiver may receive a signal that was generated by passage of symbols through a non-linear circuit. An equalizer of the receiver may equalize the received signal based on a first non-linearity compensated, inter-symbol correlated (ISC) feedback signal to generate an equalized signal. The receiver may correct a phase error of the equalized signal to generate a phase-corrected equalized signal. The phase correction may be based on a second, non-linearity compensated, inter-symbol correlated (ISC) feedback signal. | 04-17-2014 |
20140105268 | DECISION FEEDBACK EQUALIZER UTILIZING SYMBOL ERROR RATE BIASED ADAPTATION FUNCTION FOR HIGHLY SPECTRALLY EFFICIENT COMMUNICATIONS - One or more embodiments describe a decision feedback equalizer utilizing symbol error rate biased adaptation function for highly spectrally efficient communications. A method may be performed in a decision feedback equalizer (DFE). The method may include determining values of tap coefficients used by the DFE based. The tap coefficients may be determined based on an error signal that is based on an estimated inter-symbol-correlated (ISC) signal. The tap coefficients may be determined based on a set of error vector(s), where each error vector in the set represents a difference between estimated symbols generated in the receiver and expected symbols. Determining the values of the tap coefficients may include using a symbol error rate function that estimates the actual symbol error rate in the receiver, wherein the symbol error rate function receives as input the set of error vector(s). | 04-17-2014 |
20140105332 | TIMING SYNCHRONIZATION FOR RECEPTION OF HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - Methods and systems are provided for timing synchronization for reception of highly-spectrally efficient communications. An example method may include, filtering, in a receiver, a received inter-symbol correlated (ISC) signal to generate a filtered ISC signal. The method may further include locking to a timing pilot signal of the filtered ISC signal. The timing pilot signal may include a sub-harmonic frequency of a clock signal associated with the received ISC signal. A timing pilot estimate signal of the timing pilot signal may be generated. The timing pilot estimate signal may be cancelled from the filtered partial response signal to generate an output ISC signal. The timing pilot signal includes a signal at ±(1/n*Fbaud), where n is an integer greater than 2, and Fbaud is a symbol rate of the clock signal. The clock signal may be recovered from the filtered ISC signal. | 04-17-2014 |
20140105334 | Fine Phase Estimation for Highly Spectrally Efficient Communications - A receiver may process a received signal to generate a processed received signal. The receiver may generate, during a sequence estimation process, an estimate of a phase error of the processed received signal. The receiver may generate an estimate of a value of a transmitted symbol corresponding to the received signal based on the estimated phase error. The generation of the estimate of the phase error may comprise generation of one or more phase candidate vectors. The generation of the estimate may comprise calculation of a metric based on the one or more phase candidate vectors. The calculation of the metric may comprise phase shifting the processed received signal based on the estimated phase error resulting in a phase-corrected received signal. The calculation of the metric may comprise calculating a Euclidean distance based on the phase-corrected received signal and one or more symbol candidate vectors. | 04-17-2014 |
20140108892 | Method and System for Forward Error Correction Decoding With Parity Check for Use in Low Complexity Highly-Spectrally Efficient Communications - A receiver receives an inter-symbol correlated (ISC) signal with information symbols and a corresponding parity symbol. Values of information symbols are estimated utilizing parity samples that are generated from the parity symbols. One or more maximum likelihood (ML) decoding metrics are generated for the information symbols. One or more estimations are generated for the information symbols based on the one or more ML decoding metrics. A parity metric is generated for each of the one or more generated estimations of the information symbols. The parity metric is generated by summing a plurality of values of one of the generated estimations to generate a sum, and wrapping the sum to obtain a parity check value that is within the boundaries of a symbol constellation utilized in generating the information symbols. | 04-17-2014 |
20140133540 | LOW-COMPLEXITY, HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - A system may comprise circuitry that includes a sequence estimation circuit and a non-linearity modeling circuit. The circuitry may be operable to receive a single-carrier signal that was generated by passage of symbols through a partial response filter and through a non-linear circuit. The circuitry may be operable to generate estimated values of the symbols using the sequence estimation circuit and using the non-linearity modeling circuit. An output of the non-linearity modeling circuit may be equal to a corresponding input of the non-linearity modeling circuit modified according to a non-linear model that approximates the non-linearity of the non-linear circuit through which the received signal passed. | 05-15-2014 |
20140133608 | HYPOTHESES GENERATION BASED ON MULTIDIMENSIONAL SLICING - A sequence estimation circuit of a receiver may receive a sample of an inter-symbol correlated (ISC) signal corresponding to a time instant when phase and/or amplitude of the ISC signal is a result of correlation among a plurality of symbols of a transmitted symbol sequence. The sequence estimation circuit may calculate a residual signal value based on the sample of the ISC signal and based on a survivor sequence. The sequence estimation circuit may generate one or more branch vector hypotheses based on the residual signal value, where each of the hypotheses comprises a plurality of symbols. The sequence estimation circuit may generate an estimate of one or more of the plurality of transmitted symbols based on the one or more branch vector hypotheses. | 05-15-2014 |
20140140388 | Forward Error Correction With Parity Check Encoding For Use in Low Complexity Highly-Spectrally Efficient Communications - A transmitter inserts parity samples into a stream of information symbols in an inter-symbol correlated (ISC) signal. The inserted parity samples may be utilized to generate estimates of corresponding information symbols when they are received by a receiver. The information symbols may be pulse shaped by a first pulse shaping filter characterized by a first response. The parity samples may be pulsed shaped by a second pulse shaping filter characterized by a second response. The first response and the second response are diverse or uncorrelated. The transmitter may transmit the ISC signal comprising the pulse shaped information symbols and the pulse shaped parity samples. The parity samples may be generated utilizing a non-linear function over a plurality of the information symbols. The non-linear function may be diverse from a partial response signal convolution corresponding to the information symbols and is designed according to a desired SNR value at the receiver. | 05-22-2014 |
20140140446 | Method and System for Corrupt Symbol Handling for Providing High Reliability Sequences - For corrupt symbol handling for providing high reliability sequences, an inter-symbol correlated (ISC) signal is received. During sequence estimation when demodulating the received ISC signal, partial response samples in the ISC may be processed utilizing an erasure mechanism. The partial response samples are spread (e.g. interleaved) over time during modulation by a modulator. A determination is made as to whether to utilize self erasure or external erasure to process the spread partial response samples. The determination may be based on whether or not events of low SNR for corresponding ones of the partial response samples are identified. The external erasure may be utilized for processing the corresponding ones of the partial response samples when the events of low SNR are identified and the self erasure is utilized when the events of low SNR are not identifiable. Erasure results maybe fed back to the modulator. | 05-22-2014 |
20140146911 | Dynamic Filter Adjustment for Highly-Spectrally-Efficient Communications - A method and system for dynamic configuring of one or both of a transmitter pulse-shaping filter and a receiver pulse-shaping filter to generate a total partial response that incorporates a predetermined amount of inter-symbol interference (ISI). The predetermined amount of ISI is determined based on an estimation process during extraction of data from an output of the receiver pulse-shaping filter, such that performance of total partial-response-based communication matches or surpasses performance of communication incorporating filtering based on no or near-zero ISI. The reconfiguring may comprise obtaining data relating to changes affecting one or more of: the pulse-shaping filtering, and a channel and/or an interface used in the communication of data based on the total partial response, and adjusting the filter configuration, such as by determining a new optimized filtering configuration or changes to existing configurations (e.g., by applying a filtering optimization process). | 05-29-2014 |
20140161158 | JOINT SEQUENCE ESTIMATION OF SYMBOL AND PHASE WITH HIGH TOLERANCE OF NONLINEARITY - A method and system for a sequence estimation in a receiver, such as for use when receiving a sample of a received inter-symbol correlated (ISC) signal corresponding to a transmitted vector of L symbols, with L being a integer greater than 1, and with symbol L being a most-recent symbol and symbol l being least recent symbol of the vector. A plurality of candidate vectors may be generated, wherein element L−m of each candidate vector holding one of a plurality of possible values of the symbol L−m, with m is an integer greater than or equal to 1, and elements L−m+1 through L of each candidate vectors holding determined filler values. A plurality of metrics may be generated based on the plurality of candidate vectors, and based on the generated plurality of metrics, a best one of the possible values of the symbol L−m may be selected. | 06-12-2014 |
20140161170 | Feed Forward Equalization for Highly-Spectrally-Efficient Communications - A receiver may be operable to receive a signal. A sequence estimation module of the receiver may generate estimated symbols corresponding to the received signal. The generating of the estimated symbols may use tap information associated with one or both of a pulse shaper via which the signal was transmitted and an input filter of the receiver. The sequence estimation module may generate a reconstructed signal based on the estimated symbols and the tap information. A feed forward equalizer (FFE) of the receiver may adapt a plurality of tap coefficients of the FFE based on the reconstructed signal. The signal may be equalized via the FFE. The adaptation of the tap coefficients of the FFE may be based on a least-mean-square (LMS) process for minimizing a mean square of the error signal. An output signal of the FFE may comprise a power gain compensation. | 06-12-2014 |
20140233683 | REDUCED STATE SEQUENCE ESTIMATION WITH SOFT DECISION OUTPUTS - A receiver may be operable to receive an inter-symbol correlated (ISC) signal, and generate a plurality of soft decisions as to information carried in the ISC signal. The soft decisions may be generated using a reduced-state sequence estimation (RSSE) process. The RSSE process may be such that the number of symbol survivors retained after each iteration of the RSSE process is less than the maximum likelihood state space. The plurality of soft decisions may comprise a plurality of log likelihood ratios (LLRs). Each of the plurality of LLRs may correspond to a respective one of a plurality of subwords of a forward error correction (FEC) codeword. | 08-21-2014 |
20140241477 | DECISION FEEDBACK EQUALIZER FOR HIGHLY SPECTRALLY EFFICIENT COMMUNICATIONS - One or more embodiments describe a decision feedback equalizer for highly spectrally efficient communications. A method may be performed in a decision feedback equalizer (DFE). The method may include initializing values of tap coefficients of the DFE based on values of tap coefficients of a partial response filter through which said transmitted symbols passed en route to said sequence estimation circuit. The method may include receiving estimates of transmitted symbols from a sequence estimation circuit, and receiving an error signal that is generated based on an estimated partial response signal output by the sequence estimation circuit. The method may include updating values of tap coefficients of the DFE based on the error signal and the estimates of transmitted symbols. The method may include generating one or more constraints that restrict the impact of the error signal on the updating of the values of the tap coefficients of the DFE. | 08-28-2014 |
20140247904 | Pilot Symbol Generation for Highly-Spectrally-Efficient Communications - A transmitter may be operable to generate a sequence of symbols which may comprise information symbols and one or more pilot symbols. The transmitter may transmit the information symbols at a first power and transmit the one or more pilot symbols at a second power. In instances when a particular performance indicator is below a determined threshold, the first power may be set to a first value and the second power may be set to zero value. In instances when the particular performance indicator is above the determined threshold, the first power may be set to a second value and the second power may be set to a non-zero value. A value of the first power and a value of the second power may be based on an applicable average power limit determined by a communications standard with which the transmitter is to comply. | 09-04-2014 |
20140269861 | Constellation Map Optimization for Highly Spectrally Efficient Communications - A method and system for optimizing symbol mapping in partial response based communications that are based on use of pulse-shaping that incorporates a predetermined amount of inter-symbol interference (ISI). Optimizing symbol mapping symbol mapping may comprise configuring optimized constellation mapping for use in mapping and/or de-mapping data communicated using the partial response pulse-shaping. In this regard, the optimized constellation mapping may be based on a reference constellation mapping that is utilized for reference modulation scheme, and the configuring comprises applying adjustments to one or more constellation points in the reference constellation mapping. The optimized constellation mapping may be configured to optimize an applicable minimum distance for one or more selected error patterns for a given spectral compression applied during partial response based communications. The configuring of the optimized constellation mapping may be based on feedback information provided during communication of data. | 09-18-2014 |
20140286459 | MULTI-MODE ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING RECEIVER FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - A receiver may comprise a sequence estimation circuit and operate in at least two modes. In a first mode, the sequence estimation circuit may process OFDM symbols received on a first number of data-carrying subcarriers to recover a number of mapped symbols per OFDM symbol that is greater than the first number. In a second mode, the sequence estimation circuit may process OFDM symbols received on a second number of data-carrying subcarriers to recover a number of mapped symbols per OFDM symbol that is equal to the second number. The second number may be equal to or different from the first number. While the receiver operates in the first mode, the sequence estimation circuit may be operable to generate candidate vectors and process the candidate vectors using a controlled ISCI model to generate reconstructed physical subcarrier values. | 09-25-2014 |
20140301507 | Highly-Spectrally-Efficient Receiver - A receiver may be operable to receive a QAM-based, inter-symbol correlated (ISC) signal having pilot overhead of 5% at a signal-to-noise ratio (SNR). The receiver may be operable to process the QAM-based, ISC signal to output information at a particular rate with a symbol error rate lower than or equal to 1e-2. The first SNR may be at least 3 dB below a SNR required to achieve the same particular information rate and the same symbol error rate while processing a signal having zero inter-symbol interference. | 10-09-2014 |
20140321525 | HIGHLY-SPECTRALLY-EFFICIENT RECEPTION USING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING - Circuitry for use in a receiver may comprise: a front-end circuit operable to receive an orthogonal frequency division multiplexing (OFDM) symbol on a first number of physical subcarriers. The circuitry may comprise a decoding circuit operable to decode the OFDM symbol using an inter-carrier interference (ICI) model, the decoding resulting in a determination of a sequence of symbols, comprising a second number of symbols, that most-likely correspond to the received OFDM symbol, where the second number is greater than the first number. The sequence of symbols may comprise N-QAM symbols, N being an integer. The ISCI model may be based, at least in part, on non-linearity experienced by the OFDM symbol during transmission by a transmitter, propagation over a channel, and/or reception by the receiver. The ISCI model may be based, at least in part, on phase-noise introduced to the OFDM symbol during transmission by a transmitter, propagation over a channel, and/or reception by the receiver. | 10-30-2014 |
20140328428 | Multi-Mode Transmitter for Highly-Spectrally-Efficient Communications - A transmitter may comprise a symbol mapping circuit that is configurable to operate in at least two configurations, wherein a first of the configurations of the symbol mapping circuit uses a first symbol constellation and a second of the configurations of the symbol mapping circuit uses a second symbol constellation. The transmitter may also comprise a pulse shaping circuit that is configurable to operate in at least two configurations, wherein a first of the configurations of the pulse shaping circuit uses a first set of filter taps and a second of the configurations of the pulse shaping circuit uses a second set of filter taps. The first set of filter taps may correspond to a root raised cosine (RRC) filter and the second set of filter taps corresponds to a partial response filter. | 11-06-2014 |
20150043684 | HYPOTHESES GENERATION BASED ON MULTIDIMENSIONAL SLICING - A sequence estimation circuit of a receiver may receive a sample of an inter-symbol correlated (ISC) signal corresponding to a time instant when phase and/or amplitude of the ISC signal is a result of correlation among a plurality of symbols of a transmitted symbol sequence. The sequence estimation circuit may calculate a residual signal value based on the sample of the ISC signal and based on a survivor sequence. The sequence estimation circuit may generate one or more branch vector hypotheses based on the residual signal value, where each of the hypotheses comprises a plurality of symbols. The sequence estimation circuit may generate an estimate of one or more of the plurality of transmitted symbols based on the one or more branch vector hypotheses. | 02-12-2015 |
20150049843 | Combined Transmission Precompensation and Receiver Nonlinearity Mitigation - Circuitry of a transmitter may comprise a predistortion circuit cascaded with a nonlinear circuit. The nonlinear circuit may be characterized by a first response corresponding to a first error vector magnitude. A response of the predistortion circuit may be configured based on the first response of the nonlinear circuit such that a composite response of the predistortion circuit cascaded with the nonlinear circuit differs from the first response and is characterized by a second error vector magnitude that is greater or equal than the first error vector magnitude. The response of the predistortion circuit may be configured based on feedback of an output of the nonlinear circuit. The response of the predistortion circuit may be configured based on parameters received from a receiver partner of the transmitter during connection setup, in preambles, in message headers, and/or in dedicated messages. | 02-19-2015 |
20150055722 | ADAPTIVE NON-LINEAR MODEL FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - A receiver may be operable to generate estimates of transmitted symbols using a sequence estimation process that may incorporate a non-linear model. The non-linear model may be adapted by the receiver based on particular communication information that may be indicative of non-linearity experienced by the transmitted symbols. The receiver may generate a reconstructed signal from the estimates of the transmitted symbols. The receiver may adapt the non-linear model based on values of an error signal generated from the reconstructed signal, and the values of the error signal may be generated from a portion of the generated estimates that may correspond to known symbols and/or information symbols. The values of the error signal corresponding to the known symbols may be given more weight in an adaptation algorithm, and the values of the error signal corresponding to the information symbols may be given less weight in the adaptation algorithm. | 02-26-2015 |
20150063499 | TIMING PILOT GENERATION FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - Methods and systems are provided for timing synchronization for reception of highly-spectrally efficient communications. An example method may include, mapping, in a transmitter, a plurality of transmit bits to a plurality of symbols at a symbol rate that is based on an oscillator signal. The plurality of symbols may be processed via a filter. The processing may result in an inter-symbol correlated (ISC) signal. The oscillator signal may be frequency divided to generate one or more pilot signals having a frequency that is a sub-harmonic of a frequency of the oscillator signal. The pilot signal may be injected into the ISC signal. The injecting may result in an ISC signal with timing carrier. The ISC signal with timing carrier may be transmitted. Gain of the one or more pilot signals may be adjusted based on a spectral mask value associated with the transmitting. | 03-05-2015 |
20150070089 | ADAPTIVE NONLINEAR MODEL LEARNING - In accordance with an example implementation of this disclosure, a receiver may comprise a signal reconstruction circuit and a nonlinearity modeling circuit. The nonlinearity modeling circuit may be operable to generate a look-up table (LUT)-based model of nonlinear distortion present in a received signal. An entry of the LUT may comprise a signal power parameter value and a distortion parameter value. The signal reconstruction circuit may be operable to generate one or more candidates for a transmitted signal corresponding to the received signal. The signal reconstruction circuit may be operable to distort the one or more candidates according to the model, the distortion resulting in one or more reconstructed signals. The signal reconstruction circuit may be operable to decide a best one of the candidates based on the one or more reconstructed signals. | 03-12-2015 |
20150071389 | Multi-Mode Receiver for Highly-Spectrally-Efficient Communications - A receiver may be dynamically configurable, during run-time, into a plurality of modes of operation. In a first mode of operation the receiver may demodulate received signals having relative low inter-symbol correlation using a near zero ISI filter and symbol slicing. In a second mode of operation the receiver may demodulate received signals having relatively high inter-symbol correlation using an input filter configured to achieve a desired total partial response and a sequence estimation algorithm. | 03-12-2015 |
20150078491 | Highly-Spectrally-Efficient OFDM Receiver - A transmitter may comprise a symbol mapper circuit and operate in at least two modes. In a first mode, the number of symbols output by the mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter may be greater than the number of data-carrying subcarriers used to transmit the OFDM symbol. In a second mode, the number of symbols output by said mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter is less than or equal to the number of data-carrying subcarriers used to transmit said OFDM symbol. The symbols output by the symbol mapper circuit may be N-QAM symbols. While the circuitry operates in the first mode, the symbols output by the mapper may be converted to physical subcarrier values via filtering and decimation prior to being input to an IFFT circuit. | 03-19-2015 |