Abstract: This disclosure describes systems, methods, and devices related to enhanced sounding for secure mode wireless communications. A device may generate a channel sounding symbol comprising a first subcarrier and a second subcarrier, wherein a first amplitude of the first subcarrier is different than a second amplitude of the second subcarrier. The device may generate a channel sounding signal comprising the channel sounding symbol. The device may send the channel sounding signal to a second device.

Abstract: A method for phase correction, the method may include generating in parallel and by a set of phase error detectors, a set of phase error detection results (PEDRs) related to a set of blocks of digital samples, the digital samples are frequency corrected and represent optical signals conveyed over a coherent optical communication link; wherein the PEDs introduce PED noise that is indifferent to phase errors of the set of the blocks of digital samples; sending, in a sequential manner, the set of PEDRs, to a loop that comprises a loop filter; generating, by the loop, phase difference results, wherein each phase difference result is indicative of a phase difference between a certain PEDR of the PEDRs and a loop filtered PEDR generated by filtering a PEDR that precedes the certain PEDR; and processing, by a phase correction unit, the digital samples and the phase different results, to provide phase corrected digital samples.

Abstract: Various devices, systems and methods for performing targeted sleep tracking are presented herein. Multiple digital radar data streams from multiple antennas may be received. A direction optimization process may be performed to determine a first weighting and a second weighting. The first weighting may be applied to a first digital radar data stream. The second weighting may be applied to a second digital radar data stream. The weighted first digital radar data stream and the weighted second digital radar data stream may be combined to create a first directionally-targeted radar data stream. A sleep analysis can be performed based on the first directionally-targeted radar data stream. Sleep data may be output for a user based on the performed sleep analysis.

Abstract: Method and apparatus for signal detection in dynamic channels with high carrier frequency offset are provided. A coherent detector and a non-coherent detector are operated in parallel on a block of samples of an input signal to determine respective time offset candidates of the input signal. The time offset candidate obtained from the non-coherent detector is used to determine a frequency offset candidate of the input signal.

Abstract: A digital frequency modulation receiver includes a phase capturer, an adder, a digital filter and a phase estimator. The phase estimator is used to generate a first phase value according to an input signal. The adder is coupled to the phase estimator for subtracting a second phase value from the first phase value to generate a phase difference. The digital filter is coupled to the adder for performing a filtering calculation with the phase difference so as to generate a frequency variation signal. The phase estimator is coupled to the digital filter and the adder so as to update the second phase value according to the frequency variation signal.

Abstract: A method and apparatus for detecting an envelope are provided. The method and apparatus may detect an envelope of a modulating signal based on a low calculation complexity and a simple circuit configuration, by detecting an envelope for a plurality of sampling signals with equal time intervals.

Abstract: A method in a Multiple-Input Multiple-Output (MIMO) transmitter includes selecting a transmission mode from a group of modes including a spatial multiplexing mode and a transmit diversity mode. A rate matching parameter is set depending on at least the selected transmission mode. Data for transmission is formatted in one or more transport blocks, each transport block including multiple code blocks having respective lengths, in symbols, that are respective integer multiples of the rate matching parameter. The code blocks of a given transport block are mapped onto time-frequency resource elements in accordance with the selected transmission mode, such that each resource element contains data originating from only a respective one of the code blocks of the given transport block. The code blocks of the given transport block are transmitted over the time-frequency resource elements to a receiver.

Abstract: A method for acquiring a code phase shift between an input sequence and a reference sequence is provided. The method is to be implemented using an acquisition device that includes a mapping unit configured to transform the input sequence and the reference sequence respectively into an input signal and a reference signal each with a complex phase, a comparison unit configured to compare the input signal with the reference signal so as to obtain a phase coherent indicator, and calculating unit configured to obtain the code phase shift between the input sequence and the reference sequence based on a phase of the phase coherent indicator and a number of bits of the input sequence.

Abstract: A device is provided for use of an antennal base formed of two antennas which pick up the emissions present and produce two radioelectric signals S1 and S2. These two signals are used to produce at least one intermediate-frequency signal Fl by demodulation of one of the two signals by the other (autotransposition). The demodulation is carried out by firstly transposing one of the signals, S1 for example, around a given frequency F1, the signal S2 being preserved around its initial central frequency F0. Thus, whatever the central frequency F0 of the emission picked up by the antennas, the demodulation produces a signal of central frequency F1, thereafter demodulated into a given intermediate frequency Fl by a local oscillator of constant frequency F2=F1+Fl. The device is applied to the production of a device for detecting emissions and for characterizing the emissions picked up.

Abstract: A system is configured to receive a block of symbols, associated with a phase-modulated signal that includes data symbols that correspond to a payload associated with the signal, and control symbols; process the control symbols to identify an amount of phase noise associated with the control symbols; reset a phase, associated with each of the data symbols, based on the amount of phase noise and a reference phase; interleave the respective data samples, of each of the data symbols with other data samples, where the interleaved respective data samples cause errors, associated with the respective data samples, to be spread out among the other data samples and reduces an error rate relative to a prior data rate that existed before the interleaving; and perform forward error correction on the interleaved respective data samples.

Abstract: A method for carrier frequency tracking of a received signal having a burst structure includes dividing each burst into a number of segments. The carrier frequency offset of a first segment within a burst is measured to obtain a first segment carrier frequency offset measurement value. The carrier frequency offset of a second segment within the burst is corrected by a second segment carrier frequency offset correction value based on the first segment carrier frequency offset measurement value.

Abstract: Compressing a variable phase component of a received modulated signal with a second harmonic injection locking oscillator, and generating a delayed phase-compressed signal with a fundamental injection locking oscillator, and combining the phase-compressed signal and the delayed phase-compressed signal to obtain an estimated derivative of the variable phase component, and further processing the estimated derivative to recover data contained within the received modulated signal.

Abstract: A method of generating inphase and quadrature signals from a polar receiver providing a phase derivative signal and an envelope magnitude signal comprising receiving an estimated phase derivative signal; generating an estimated phase signal; mapping the estimated phase signal to an angular value; converting the estimated phase signal to an inphase signal and a quadrature signal based on the angular value; and, providing the inphase signal and quadrature signal to a demodulation circuit.

Abstract: A symbol clock recovery circuit is provided for a data communication system using coherent demodulation. The symbol clock recovery circuit comprises an analog-to-digital converter comprising a first input for receiving a coherent-detected baseband analog signal derived from a carrier signal, a second input for receiving an adapted symbol clock signal, and an output for outputting a digital signal comprising a frame having a preamble with at least two symbols. The symbol clock recovery circuit comprises further a phase shifting unit comprising a first input for receiving a symbol clock signal derived from the carrier signal, and a timing detector, comprising a first input for receiving the digital signal from the analog-to-digital converter and an output for providing a signal comprising information about an optimum sample phase to the phase shifting unit.

Abstract: The present disclosure provides a system, apparatus and method to reduce phase noise associated with a received data signal, while optimizing system performance. An optimal length of a digital filter, employed in a carrier phase recovery process, is determined such that phase noise is reduced in the received data signal. Reduction of the phase noise present in the received data signal leads to improved receiver performance. The optimal length of the digital filter may be continuously performed, resulting in optimal performance of the receiver.

Abstract: Provided are a device and method for estimating carrier frequency offset of OFDM signals transmitted and received through a plurality of polarized antennas that may accurately estimate carrier frequency offset used for carrier frequency synchronization acquisition when there is interference between polarized waves.

Abstract: Provided are a method and apparatus (receiver) of receiving and processing a radio signal in a transmitter-receiver environment. The radio signals are transmitted across a wireless interface using Ultra Wideband (UWB) pulses. A transmitted reference approach is utilized. The radio signal include pairs of UWB pulses with each pair of pulses separated by a fixed time delay. The two pulses are then combined to provide for improved noise immunity.

Abstract: A method of embedding information within a burst carrier signal, the method comprising modulating meta-data using a modulator such that a meta-carrier signal results, lowering a Power Spectral Density (PSD) of the meta-carrier signal by Direct Sequence Spread Spectrum (DSSS) chipping the meta-carrier signal using a linear Pseudo-Random Number (PRN) sequence, embedding one or more modulated symbols of the meta-carrier signal within an unused portion of one or more quadrants of a modulation constellation of a burst carrier signal such that a composite carrier signal results, and synchronously transmitting the composite carrier signal using a transmitter such that symbols of the meta-carrier signal are synchronized with symbols of the burst carrier signal.

Abstract: A MIMO detection method for a receiver in a MIMO system using N-QAM for modulation, the MIMO detection method including generating a plurality of symbol vector sets and a plurality of search radiuses, selecting a candidate symbol vector set corresponding to a highest level of a multilevel structure of N-QAM constellation, generating a search space corresponding to a lower level of the multilevel structure of N-QAM constellation according to the selected candidate symbol vector set, confirming which level the search space corresponds to, and generating a detection signal according to the search space when the level of the search space is the lowest level of the multilevel structure of the N-QAM constellation.

Abstract: A wireless communications device includes a receiver, and a demodulator coupled downstream from the receiver and configured to use a continuous phase modulation (CPM) waveform to non-coherently demodulate a received signal. The demodulator is configured to generate waveform banks, each waveform bank having a respective different frequency offset associated therewith, determine a correlation output metric for each waveform bank, select a waveform bank for demodulating the received signal based upon the correlation output metrics of the waveform banks, and demodulate the received signal using the selected waveform bank and the associated frequency offset.

Abstract: An RF feedback receiver arrangement includes a reference signal provider configured to provide, in a normal operating phase, a first reference signal having a first reference signal frequency, and provide, in a calibration operating phase, a second reference signal having a second reference signal frequency different from the first reference signal frequency. In addition, the RF feedback receiver arrangement includes a signal property detector configured to detect a transmit signal property of the transmit signal in the normal operating phase based on combining the first reference signal with a transmit signal or with a signal derived from the transmit signal, and to obtain, in the calibration operating phase, a calibration signal based on combining the second reference signal with the transmit signal or the signal derived from the transmit signal, which describes a disturbing portion introduced into the detected transmit signal property by the RF feedback receiver arrangement itself.

Abstract: The invention includes a method for transmitting and detecting high speed Ultra Wideband pulses across a wireless interface. The transmitter includes a serializer and pulse generator. The receiver comprises a fixed delay line, multiplier, local serializer (with a sequence matching the transmitter), digital delay lines, low noise amplifier and logic fan-out buffer along with an array of D flip-flop pairs. Each flip-flop pair is enabled, at fixed time increments, to detect signals at a precise time; the timing is controlled by the pseudo-random sequence generated by the local serializer. A local tunable oscillator is controlled by detecting the phase change of the incoming signal and applying compensation to maintain the phase alignment and clock synchronization of the receiver to the clock reference of the transmitter. The invention uses a pair of pulses with a fixed delay and then relies on mixing the two to provide better noise immunity.

Abstract: An adaptive time delay control system is provided for matching the propagation time delay between two samples of a signal traveling through two independent paths so that they can be coherently combined for additional signal processing functions such as cosite interference cancellers, adaptive interference cancellers and adaptive beam formers. The adaptive time delay control system and associated method advantageously provide improved continuous matching of the two channels over a wider adjustment range while preserving both convergence speed over the full range and minimum jitter upon convergence by using composite autocorrelation functions to control (adjusting) a matching time delay in one channel.

Abstract: Disclosed are data transmission/reception apparatus and method that may be applied to a case where additional data is to be transmitted in a CE-OFDM modulation/demodulation scheme that satisfies an OFDM feature which is robust against multipath fading and simultaneously has a feature that amplitude is constant. Service channel information, modulation parameter information of a physical layer, and the like, may be transmitted by using an additionally secured information channel. If using this, a service search time may be saved, and power of a receiver may be reduced.

Abstract: This invention provides methods for a GPS device to resolve timing errors as applicable to a AGPS navigation solution, and, in particular, to solutions involving GNSS positioning and timing with limited assistance such as indoors or in a heavily obscured location, where the time of transmit of satellite signals is not directly extractable from the navigation message data. In particular the invention concerns the reconstruction of time-of-transmit from the course acquisition code of weak signals or where assisted-GNSS are employed.

Abstract: An adaptive beam steering control system suitable for multiple element systems is provided for coherently forming a beam and tracking a dynamic scenario of a rapidly fading environment. The adaptive beam steering control system and associated method advantageously provide improved continuous beam steering with a faster response time and higher precision than normally attainable by using the greater slope of the nulling error function to perform the beam steering function. Although reciprocity of nulling and beam steering is normally only true for a single pair of elements, the method of the invention extends the process to larger arrays of elements.

Abstract: A communications subsystem for a wireless device for correcting errors in a reference frequency signal. The communications subsystem comprises a frequency generator for generating the reference frequency signal and a closed loop reference frequency correction module that generates a reference frequency adjustment signal for correcting the reference frequency signal when the communications subsystem operates in closed loop mode. The subsystem further includes an open loop frequency correction means that that samples values of the reference frequency adjustment signal during the closed loop mode and generates a frequency correction signal for correcting the reference frequency signal when the communications subsystem operates in a mode other than closed loop mode.

Abstract: A method of improving sensitivity in the demodulation of a received signal by a receiver over an arbitrary measurement time epoch, said method comprising the steps of correlating said received signal with a local replica of pseudo noise code in a coherent fashion creating a correlation signal and utilizing a Viterbi phase state keying trellis demodulation with a variable resolution of phase states over 0 to 360° to demodulate the radio frequency phase trajectory of said correlation signal throughout the measurement time epoch for improving sensitivity in the demodulation of a received signal.

Abstract: Methods and systems to compute likelihood measures of demodulated, complex-coordinate data points, to and dynamically scale the likelihood measures as a function of a channel statistic, and to decode the data points from the scaled likelihood measures. Likelihood measures may be computed relative to all points, or a subset of points of a reference constellation, such as a subset of one or more nearest constellation points. Likelihood measures may be scaled as a function of a channel frequency response variance amongst a plurality of carriers, such as carriers of an OFDM signal, and/or as a function of a channel impulse response variance.

Abstract: This invention relates to an apparatus and a method for monitoring statistical characteristics of phase noises, as well as to a coherent optical communication receiver. The apparatus for monitoring statistical characteristics of phase noises comprises an argument calculating unit (203), for obtaining an argument of a signal input thereto; an unwrapping unit (204), for unwrapping the argument obtained by the argument calculating unit (203) to obtain a phase signal (205); a delaying unit (207), for delaying the phase signal; a differentiating unit (209), for obtaining a difference between a phase signal currently obtained by the unwrapping unit (204) and a phase signal delayed by the delaying unit (207); a modulus squaring unit (210), for obtaining a square of the modulus of the difference; and an averaging unit (211), for averaging squares of moduli of a plurality of differences obtained by the modulus squaring unit (210) to obtain a mean-squared differential phase (MSDP) value.

Abstract: Embodiments of the present invention provide systems, devices and methods for modeling and correcting amplitude and quadrature phase errors generated within analog components of a receiver. A frequency-dependent correction method is employed that closely tracks the frequency dependent nature of the mismatch between the I and Q polyphase filter responses. In particular, digital correction is performed on a signal based on a modeled error function generated during a calibration of the receiver.

Abstract: A method and apparatus are disclosed for detecting a pilot signal in a wireless receiver using coherent combining/noncoherent detection techniques. Coherent combining/noncoherent detection techniques are used to detect the pilot signal whenever the receiver is already frequency locked, or otherwise known to have a small frequency offset Conventional noncoherent combining/noncoherent detection techniques are utilized to initially acquire the timing of the forward channel. Once the receiver is frequency locked, coherent combining/noncoherent detection techniques may be used to continuously detect the pilot signals. After the receiver is frequency locked, the residue frequency error is small over several consecutive correlator outputs The correlator outputs can thus be combined coherently (since the frequency error is known to be small), and the phase dependency is then eliminated by noncoherent detection.

Abstract: A system for processing a received signal having at least one code applied thereto, the received signal having a frequency, the system comprising: first correlator circuitry arranged to correlate the received signal with a first code to provide an output; second correlator circuitry arranged to correlate the received signal with a second code to provide an output, wherein the first code and the second code are different; and processor for processing together the outputs of the first and second correlator circuitry to cancel the frequency.

Abstract: An optical communication device using a digital coherent reception system includes a phase detector configured to generate, based on a signal obtained in a course of digital signal processing, a phase signal indicating a displacement of a sampling of a reception signal, a clock switch-determiner configured to switch from an reference clock to a clock of transferred data when a value of an amplitude of the phase signal exceeds a given threshold value, and a selector configured to synchronize the sampling of the reception signal and an internal clock of the digital signal processing with the reference clock at start time or signal loss time, and synchronize the sampling of the reception signal and the internal clock with the line clock of the reception signal except for the start time and the signal loss time.

Abstract: Certain embodiments of the present disclosure propose methods and systems for classifying the Doppler spread based on the output of the frequency-tracking loop (FTL) discriminator in WiMAX systems to improve the performance of the channel estimation. The Doppler spread may be classified as low, medium or high based on the statistics of the output of the discriminator in the fine-tracking mode.

Abstract: A method and apparatus for measuring parameters of a receiver having a mixer for generating an I signal and a Q signal using an input signal, an I channel circuit for processing the I signal, and a Q channel circuit for processing the Q signal. The method includes feeding the receiver a first testing signal before the mixer. The method includes feeding the receiver a second testing signal on the I channel circuit. The method includes feeding the receiver a third testing signal on the Q channel circuit. The method includes measuring I/Q quadrature deviation and I/Q delay imbalance of the receiver using the first, the second, and the third testing signals. This separates the I/Q quadrature deviation and I/Q delay imbalance.

Abstract: The present invention relates to a phase recovery device, phase recovery method and receiver for 16 QAM data modulation.

Abstract: A communications subsystem for a wireless device for correcting errors in a reference frequency signal. The communications subsystem comprises a frequency generator for generating the reference frequency signal and a closed loop reference frequency correction module that generates a reference frequency adjustment signal for correcting the reference frequency signal when the communications subsystem operates in closed loop mode. The subsystem further includes an open loop frequency correction means that that samples values of the reference frequency adjustment signal during the closed loop mode and generates a frequency correction signal for correcting the reference frequency signal when the communications subsystem operates in a mode other than closed loop mode.

Abstract: The present invention pertains to demodulation of GMSK signals by estimating a carrier frequency of the signal having a carrier residual, basebanding the signal, tracking the signal's carrier frequency, removing the carrier residual, detecting a data burst, generating a bank of poly-bit matched filters, applying the bank of poly-bit matched filters to the signal, determining a magnitude and phase of the output of each poly-bit filter of the bank of poly-bit matched filters, determining a maximum magnitude, determining the location of a baud center, generating a plurality of correlation signals by applying the bank of poly-bit matched filters at the baud center, estimating a carrier phase, removing the estimated carrier phase, applying a Viterbi decoding algorithm to the signal, and estimating the transmitted data sequence.

Abstract: Various aspects and embodiments of the present invention derive statistics of received signal quality and use these statistics to jointly control operation of timing recovery, carrier recovery, automatic gain control, and equalization functions.

Abstract: A space domain filter detecting method in a multi-antennas wireless communication system, which processes time and space domain interference differently. The space domain filter detecting method comprises the following steps: firstly, the received signals are matched-combined in time domain and space domain; secondly, using the combined signals as an observation value, the space domain filtering is performed; thirdly, an estimated value is subtracted from the filtered signals, and the result is taken as a detection output, which is sent to a determiner in a non-error control coding system to get a hard determination output or is sent to a determiner in an error control coding system to get a soft determination output that is finally sent to a coder. The method promotes the transmission rate and the anti-interference ability and advances the spectrum efficiency.

Abstract: Provided is a correlation scheme selecting apparatus and method that can acquire initial synchronization efficiently by calculating frequency error criterion threshold between correlation schemes and selecting a correlation scheme for each region when a correlation value is calculated for initial sync in a communication system with carrier frequency errors. The method for selecting a correlation scheme based on a carrier frequency error includes: calculating mis-detection probability values based on a normalized frequency offset for each correlation scheme; determining as a frequency-error criterion threshold a crossing point of graphs of the calculated mis-detection probability values for each correlation scheme; and selecting a correlation scheme based on the determined frequency-error criterion threshold.

Abstract: The present invention relates an apparatus and method of estimating a signal-to-noise ratio (SNR) of a received signal when the received signal has a timing offset. An apparatus for estimating a signal-to-noise ratio (SNR) according to an exemplary embodiment of the present invention includes a fast Fourier transform (FFT) unit that performs a fast Fourier transform on a received signal to convert the received signal into a frequency domain signal; a preamble selector that extracts a preamble from the frequency domain signal; a correlator that correlates the preamble to a preamble reference signal generated by a receiver to calculate a correlation value; an entire power estimator that calculates entire power; a noise power estimator that applies a differential demodulation method to the correlation value to remove a timing offset and calculate noise power; and an estimating unit that uses the entire power and the noise power to estimate the signal-to-noise ratio (SNR).

Abstract: A detection method of space domain maximum posteriori probability (MAP) in a wireless communication system is a kind of detection technique of space domain MAP in a multi-aerial wireless communication system, which makes the detection of iteration soft interference elimination for the interference signals in the other moments, and makes the MAP detection or the simplified MAP detection for the all signals in current time and space domain. It includes the steps of: taking a fading block as a unit; the received signals are matched and combined in time domain and space domain, and calculating an equivalent channel matrix; making the sequence detection, calculating estimation and variance of the signals before the ending of detecting internal iteration; when the internal iteration detection finishes, the result is outputted, or is outputted after hard decision.

Abstract: The present invention discloses a frequency offset detecting apparatus and method for use in a digital coherent optical receiver.

Abstract: A phase-locked loop includes a sample selector configured to select a set of samples from an oversampled portion of a data signal, a dynamic phase decision control circuit configured to indicate whether a predetermined number of edges is present in the set of samples, and a phase detector configured to determine a skew condition and a direction of the skew condition of the set of samples based on the indication of the dynamic phase decision control circuit. The phase detector is configured to produce a set of skew detection signals based on at least one skew condition determination. The phase-locked loop further includes a loop filter configured to filter the set of skew detection signals. The loop filter is also configured to produce a set of phase adjustment signals based on the set of skew detection signals. The sample selector is configured to select a set of samples from the oversampled portion of the data signal, based on the set of phase adjustment signals.

Abstract: The invention concerns the reduction of interference in a communication signal sent through a communication channel, where this interference is a performance limiting factor. The communication channel is any channel that can be described with memory elements. A Soft Input Soft Output receiver of a communication signal receives the communication signal and a priori information about the communication signal. Next creating candidate vectors having 1 to K samples by iteratively drawing samples using Gibbs sampling and using the a priori information. If a drawn kth sample of a candidate vector has not changed value for a predetermined number of created candidate vectors, then the value of the drawn kth sample is changed.

Abstract: A detect decision is made by non-coherently combining results from correlating a preamble (CAZAC) sequence with base/root sequences used in the cell and setting a detection threshold based on those combined results. Another threshold can be set based on coherently combining results from correlating the preamble sequence, in which case the detect decision is based on satisfying either one of the thresholds. Where the sequence repeats in the same preamble, the results that are combined are from correlating the first instance of the CAZAC sequence and from correlating the second instance of the CAZAC sequence. Where the sequence does not repeat, different segments of the CAZAC sequence, each less than the whole and not necessarily of the same length, are correlated for a partial correlation on each segment, then the segments are combined and used to set the detection threshold.

Abstract: A power efficient technique is used to demodulate the coded overhead channels of a geosynchronous (GEO) satellite uplink. A coherent receiver used in a wireless communication system is able to determine the information conveyed in the overhead channel, by effecting channel estimates from codewords extracted from a pilot signal. A valid set of codewords is established. Pilot symbols are extracted from a pilot signal and a channel estimate is made from the pilot signal. Codewords in the set of valid codewords are correlated and a channel phase ambiguity in the signals is removed and a codeword with the largest correlation is chosen. The chosen codeword is used to create a revised channel estimate.

Abstract: A wireless receiver (100) is provided, comprising: a non-coherent signal detector (130) configured to receive an incoming signal and perform a non-coherent signal analysis in response to a first control signal; a coherent signal detector (140) configured to receive the incoming signal and perform a coherent signal analysis to extract coherently-encoded data from the incoming signal in response to a second control signal; and a receiver circuit (160) configured to process the coherently-encoded data. The non-coherently-encoded data provides an indication as to whether the incoming signal includes the coherently-encoded data, and the coherent signal detector is further configured to enter in a low power sleep state in response to a third control signal.