Abstract: Methods of detecting a pulse sequence in a received signal are disclosed, each of which entails operating on samples of the received signal. One method entails determining a correlation of samples with a reference sequence, and detecting the pulse sequence based on the correlation. Another method entails selecting a reference sample associated with a pulse, and detecting the pulse sequence by analyzing samples based on one or more lengths of a time hopping interval and the reference sample. Another method entails selecting a reference sample associated with non-restricted time hopping intervals, and detecting the pulse sequence by analyzing samples that are based on substantially one or more lengths of a half pulse interval and the reference sample. Further, disclosed is a method of determining a timing drift by selecting samples, determining a time delay between the selected samples, and determining the timing drift based on the determined time delay and an expected time delay.

Abstract: According to embodiments of the present invention, a receiver is provided. The receiver includes an envelope detector configured to generate a waveform corresponding to an envelope of a signal received by the receiver, a carrier recovery circuit configured to generate a carrier signal based on the waveform, wherein the carrier signal has a frequency corresponding to a center frequency of the received signal, and a template generator configured to generate a local template signal based on the waveform, the local template signal including a plurality of pulses. According to further embodiments of the present invention, a method of controlling a receiver is also provided.

Abstract: In a method for generating a signal quality indicator, a correlation signal is generated from a received signal and a spreading sequence. A magnitude signal is generated from the correlation signal. A time-domain averaged signal is generated based on the magnitude signal and at least a first time delayed version of the magnitude signal delayed by at least one symbol period. A peak-to-average signal is generated based on the time-domain averaged signal.

Abstract: A method and apparatus to align data blocks in a data signal and a reference signal to increase cross-correlation between the data signal and the reference signal as compared to the unaligned data and reference signals and cancel interference in the data signal in the frequency-domain under changing conditions and in the presence of the data signal.

Abstract: A signal processing apparatus for determining whether a receiving signal is a target signal is provided. The apparatus includes: a sampling device for sampling the receiving signal to generate a plurality of sampled values; a first calculation device, coupled to the sampling device, for generating a plurality of first values according to the sampled values and a plurality of reference values; a second calculation device, coupled to the first calculation device, for grouping the first values into a plurality of value groups, respectively calculating the value groups to generate a plurality of second values and generating a determination value by calculating the second values; and a determination device, coupled to the second calculation device, for determining whether the receiving signal is the target signal by comparing the determination value with a threshold value.

Abstract: Systems and methods are provided for fast and precise estimation of frequency with relatively minimal sampling and relatively high tolerance to noise.

Abstract: Systems and methods are provided for fast and precise estimation of frequency with relatively minimal sampling and relatively high tolerance to noise.

Abstract: Disclosed is an improved channel estimation by post-processing of the channel response that is generated by a Golay correlator The processing is done using time-domain operations such as gating and filtering. Gating is performed on the estimated channel response taps in order to reduce the noise level. Pre-filtering the channel response through a filter matched to the transmitted pulse-shape improves the probability of detecting the channel peaks. Post-filtering the processed channel impulse response to eliminate the high frequency effects that are added by the windowing and gating operations.

Abstract: Provided is a receiving device which, even when a temporary degradation occurs in the propagation path environment during an AFC tracking operation, does not require an initial lead-in operation when the propagation path environment returns to normal and which has lower power consumption and shortened time during which communication is not possible; also provided are a receiving method and a computer program. This receiving device calculates the variance of the phase rotation angle relative to a reference signal, compensating for frequency error if the rotation angle variance is less than a pre-set threshold value (TH), and stopping frequency error compensation if the rotation angle variance is greater than or equal to the threshold value (TH).

Abstract: There is provided a method of encoding and decoding data using an error control code having a codebook G. The codebook G is a sub-codebook of a codebook P. Each codeword g in the sub-codebook G has an autocorrelation amplitude that is different from and higher than each correlation amplitude between g and each of the other codewords in the sub-codebook G. In one specific embodiment in which the codebook P is that of a Reed-Muller code, using G instead of P reduces the likelihood of the presence of more than one maximum correlation amplitude when computing the non-coherent decision metric during decoding.

Abstract: The invention relates to apparatuses, methods, a system, computer programs, computer program products and computer-readable media. Matched-filtered samples are conveyed instead of antenna samples, so that data rates in the interface between a remote radio head and the BTS or base band hotel may be lower. For detecting data, the matched filtered data samples are processed by using information on the radio channel.

Abstract: A method of determining a set of Zero Correlation Zone (ZCZ) lengths, comprises: determining the length of a root sequence, and selecting such a set of ZCZ lengths that, for any cell radius, the maximum number of preambles obtained from a ZCZ length which is selected from the selected set of ZCZ lengths is closest to the maximum number of preambles determined from a ZCZ length which is selected from the set of all integers, wherein the maximum number of preambles is determined from the length of the root sequence and a ZCZ length selected. This disclosure provides a technical solution for selecting a better limited set of ZCZ lengths by which signaling overload is reduced.

Abstract: A method and apparatus removes bias from an initial signal-to-interference ratio (SIR). In an exemplary embodiment, an initial SIR calculator in an SIR processor calculates the initial SIR based on the signal received by the wireless receiver, while an average SIR calculator in the SIR processor generates an average SIR. Using the average SIR, a bias remover removes the bias from the initial SIR.

Abstract: Embodiments of the present invention relate to the detection of synchronization marks in data storage and retrieval. According to one embodiment, synchronization marks are detected from the output of a matched filter, upstream of the Viterbi detector. This approach avoids the delay associated with the latency of the Viterbi output, thereby allowing time to align parity framing and to properly start the time-varying trellis. Certain embodiments disclose 34- and 20-bit primary synchronization marks located at the beginning of a data region. Other embodiments disclose 16-, 20-, and 24-bit embedded synchronization marks located within a data region.

Abstract: An apparatus and method for reducing power consumption of a receiver of a mobile communication system are provided. The apparatus includes an adaptive multi-tap segment channel estimator for determining a segment size according to a delay spread value for each channel tap, for determining a channel estimation frequency by determining a sum of segment block energy, and for allocating each segment to the channel estimator.

Abstract: Apparatus comprises: means configured to obtain a set of plural samples of signals, the set comprising at least one sample for each of L antenna elements of a receiver, where L is an integer greater than two and where the samples are of an RF signal that has been downconverted by a downconversion frequency; means configured, for each antenna element, to perform autocorrelation on the samples relating to that antenna element; means configured to sum the results of autocorrelation for all antenna elements; means configured to convert the summed results into the frequency domain; means configured to determine a maximum value of the summed results in the frequency domain; and means configured to use the determined maximum value to provide an output indicative of an offset between a carrier of the RF signal and the downconversion frequency.

Abstract: A device for detecting a useful signal by detecting a periodic signal contained in the useful signal exhibits a correlation unit for correlating the signal with the sign of the signal, taking into consideration a time delay. It also comprises an amplitude estimating unit for estimating the amplitude of the signal and a decision unit which is connected downstream of the amplitude estimating unit and the correlation unit, for deciding about the presence of the periodic signal.

Abstract: A method and apparatus for measuring channel quality over which has been transmitted a sequence of symbols produced by encoding and constellation mapping a source data element sequence. A sequence of received symbols is received over the channel. The sequence of received symbols is de-mapped based on a first channel quality indicator previously transmitted to a transmitter of the sequence of symbols. The de-mapped symbols are decoded to produce a decoded output sequence. In some embodiments, the decoding may be based on the first channel quality indicator. The decoded output sequence is re-encoded to produce a re-encoded output sequence. The de-mapped symbols are correlated with the re-encoded output sequence to produce a second channel quality indicator. The second channel quality indicator is transmitted to the transmitter to adaptively select a type of mapping based on the second channel quality indicator.

Abstract: Apparatus and methods for calculating constant amplitude zero auto-correlation sequences are disclosed. One method includes calculating an argument of trigonometric functions used for calculating a constant amplitude zero auto-correlation sequence based at least on additive recursion of an input sequence root constant and without multiplication by a variable. A constant amplitude zero auto-correlation sequence is then computed using a CORDIC algorithm configured to calculate trigonometric functions used in determining the sequence without performing multiplication operations and based on the calculated argument. The disclosed methods and apparatus may be applied, in particular, to efficiently computing Zadoff-Chu sequences in preamble detection in particular physical random access channels in Long Term Evolution LTE communication systems. By allowing computation of such sequences, memory requirements can be reduced.

Abstract: A method for receiving modulation signals includes receiving a plurality of multiplexed modulation signals each transmitted from multiple antennas of a communication partner, wherein each modulation signal includes a pilot symbol sequence consisting of plural pilot symbols used for demodulation. Each of the pilot symbol sequences is inserted at the same temporal points in the each modulation signal. The pilot symbol sequences are orthogonal to each other with zero cross correlation among the plurality of modulation signals, each pilot symbol having a non-zero amplitude, the quantity of the plural pilot symbols in each sequence being greater than the quantity of the plurality of transmitted modulation signals.

Abstract: Examples of systems and methods are provided for converting an analog input signal to a digital output signal. A system may include a current mode (CM) digital-to-analog converter (DAC) circuit to provide a DAC current. A comparator circuit may be configured to generate a comparator signal in response to an error signal determined based on the DAC current and the analog input signal. A successive approximation register circuit may be configured to generate at least one of a DAC-code signal or the digital output signal, in response to the comparator signal. The DAC-code signal may be used by the CM DAC circuit to control the DAC current.

Abstract: A method for detecting wireless microphone signals based on an augmented spectral correlation function is provided. The method includes obtaining an augmented spectral correlation function (SCF) of acquired digital signals based on a SCF of the digital signal and a conjugate SCF proposed in the present invention, calculating a statistic, and comparing it with a decision threshold simulated or calculated through a predetermined method to determine whether the digital signal is a wireless microphone signal. With the proposed augmented SCF, the present invention overcomes a difficulty in sensing TV white space, namely, the inability of most existing detection methods to effectively distinguish between narrowband interferences and wireless microphone signals.

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 example method for controlling a continuous time linear equalizer includes: developing a voltage histogram of a signal present at an output of a continuous time linear equalizer; developing a quality factor for the voltage histogram; comparing the quality factor with a prior quality factor; decreasing an equalization of the continuous time linear equalizer if the quality factor is less than the prior quality factor and increasing the equalization of the continuous time linear equalizer if the quality factor is greater than the prior quality factor.

Abstract: Provided is a transmitter for transmitting signals by means of the STBC method or the DSTBC method, wherein communication is carried out effectively. The transmitter for transmitting signals by means of the STBC method or the DSTBC method has the following configuration. A frame in which synchronization words are arranged at specified positions is used. An encoding means in the transmitter encodes the entire frame to be transmitted including the synchronization words, by means of the STBC method or the DSTBC method. It is also possible to implement a communication system and a communication method for communicating signals by means of the STBC method or the DSTBC method.

Abstract: The present disclosure provides a receiving device including, a receiver configured to receive a signal that is transmitted via a propagation path and is modulated by a predetermined system prescribed by a predetermined standard, a demodulator configured to demodulate a received signal, an estimator configured to estimate a signal-to-noise ratio relating to the propagation path, obtained from a data signal included in the demodulated received signal, and a corrector configured to correct an estimated signal-to-noise ratio in accordance with a transmission parameter obtained from the received signal.

Abstract: A non-coherent detection apparatus includes, inter alia, a correlation unit, a frequency offset estimator, and a signal detector. The correlation unit obtains a differential phase signal by multiplying a complex conjugate value of a delay signal obtained by delaying a received signal by (N+1) chips by the received signal, sums-up resultant values obtained by multiplying each component of the differential phase signal by each component of a correlation sequence and outputs a correlation signal. The frequency offset estimator estimates a frequency offset based on a value obtained by accumulatively summing-up the correlation signals corresponding to preamble portions of the received signal. The signal detector detects an original signal from the received signal based on a size of a real-number part of a resultant value obtained by multiplying the frequency offset estimated by the frequency offset estimator by the correlation signal corresponding to a PHY payload portion of the received signal.

Abstract: A method for determining an overlap and add length estimate comprises determining a plurality of correlation values of a plurality of ordered frequency domain samples obtained from a data frame; comparing the correlation values of a first subset of the samples to a first predetermined threshold to determine a first edge sample; comparing the correlation values of a second subset of the samples to a second predetermined threshold to determine a second edge sample; using the first and second edge samples to determine an overlap and add length estimate; and providing the overlap and add length estimate to an overlap and add circuit.

Abstract: A method of and system for determining cross-polarization isolation is described. In one embodiment, a modulated signal is obtained from a communication link. The modulated signal includes a modulated co-polarized signal component and a modulated cross-polarized signal component. Cross-polarization isolation is determined using the modulated co-polarized signal component and the modulated cross-polarized signal component. The determined cross-polarization isolation can be used to adjust an antenna.

Abstract: There is provided a radio receiver including: a first matched filter, a second matched filter, a first frame synchronization determining unit and a first phase determining unit. The first matched filter performs matching processing on the basis of N first tap coefficients and sign information of a received digital signal to obtain first output data. The second matched filter performs matching processing on the basis of M (M is a natural number smaller than the N) second tap coefficients, the sign information and amplitude information of the received digital to obtain second output data. The first frame synchronization determining unit determines a first frame synchronization timing of the received digital signal on the basis of the first output data. The first phase determining unit determines a first phase amount of the received digital signal on the basis of the second output data and the first frame synchronization timing.

Abstract: A method includes a step of correlating a received signal with a pilot sequence to determine a correlation result. The method further includes a step of determining a channel estimate based on a Minimum Mean Square Error scheme that is conditional to an observed parameter, wherein the observed parameter includes the correlation result.

Abstract: A continuous time counter and method of counting are provided, comprising a sequence of adding stages which build up the output based on the inputs by progressively adding new values to opposite ends of an output stack. The counter provides for fast and reliable continuous time counting operations.

Abstract: The present invention discloses an interference cancellation method and apparatus, wherein the method includes: determining a strong interference code channel among all code channels that carry a received signal by a receiver, and determining a signal that corresponds to the strong interference code channel to be a strong interference signal, wherein the received signal is a signal that has been matched filtered; obtaining the reconstructed strong interference signal based on the determined strong interference signal reconstructed from a system matrix by the receiver; performing the interference cancellation for the received signal by utilizing the reconstructed strong interference signal, and obtaining the signal whose interference have been cancelled by the receiver.

Abstract: For estimating a difference between a frequency of a base station and a locally generated frequency of a mobile equipment in a mobile communications network, wherein at least a signal in a plurality of signals transmitted from the base station and received by the mobile equipment comprises a plurality of symbols each of which includes a cyclic prefix, a correlation between a symbol and its cyclic prefix is used for estimating the frequency difference.

Abstract: According to one embodiment, a frequency offset compensation apparatus includes a first estimation unit, a second estimation unit, a setting unit, a synthesis unit and a compensation unit. The first estimation unit estimates a first rotation. The second estimation unit estimates a second rotation. The setting unit sets a weighting factor for the second rotation to a first value if a received power is less than a threshold value, and sets the weighting factor for the rotation to a second value being smaller than the first value if the received power is not less than the threshold value. The synthesis unit calculates a compensation value. The compensation unit compensates for a frequency offset.

Abstract: A method of correlating a digital communications signal is described. In an example, a window is defined equal to a portion of an epoch of the digital communication signal. The digital communication signal is then correlated across the window. A determination is made as to whether a correlation peak results from the correlating. Timing parameters are then established for receiving additional digital communication signals in response to presence of the correlation peak.

Abstract: A set of one or more receiver parameters is adjusted. It is determined whether to adjust the set of receiver parameters. In the event it is determined to adjust the set of receiver parameters, a new set of values is generated for the set of receiver parameters using a cost function (where the cost function does not assume a noise signal in a receive signal to have a particular statistical distribution) and the set of receiver parameters is changed to have the new set of values.

Abstract: A system including a control module and a correlation module. The control module receives signals, including subcarriers having frequencies in a frequency band, via a plurality of antennas, and divides the frequency band into sub-bands each including a plurality of the subcarriers. The correlation module generates sets of correlation values by correlating symbols in the sub-bands with a plurality of preamble sequences. A set of correlation values is generated for one of the plurality of antennas and is generated based on the preamble sequences. The control module generates sums by adding selected correlation values from the sets. The selected correlation values in a sum are generated respectively for the plurality of antennas and are generated based on one of the preamble sequences. The control module detects a preamble sequence in the signals by determining whether a largest one of the sums is greater than or equal to a predetermined threshold.

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: In one embodiment, a method for demodulating and searching for a preamble signal containing a complex phasor signal is disclosed. The complex phasor is demodulated using a phasor-rotated fast transformer. A received signal is correlated with a spreading code to produce a correlated signal. The correlated signal is coherently accumulated to produce a coherently accumulated signal. A first phasor-rotated signal transformation is performed on a real component of the coherently accumulated signal, and a second phasor-rotated signal transformation is performed on an imaginary component of the coherently accumulated signal. Finally, the signal power of the transformed real and imaginary components of the coherently accumulated signal is determined.

Abstract: The modulator creates modulated signals from input signals. The series/parallel converter creates subcarrier modulated signals from the remaining data and modulated signals. The arithmetic operator arranges and combines a first number of elements of the subcarrier modulated signals from the first one and a second number of elements of a data series from the first one each multiplied by a given amplitude coefficient to create arithmetic operation data. The IFFT executor executes the inverse fast Fourier transformation of the arithmetic operation data. The combiner creates baseband signals from the arithmetic operation results. The determiner calculates the peal-to-average power ratio of the baseband signals. The processing of the arithmetic operator to the determiner is repeated while changing at least one of given numbers until the baseband signals complying with a given criterion are detected.

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: According to one embodiment, a method of transmitting a broadcast signal includes: encoding physical layer pipe (PLP) data for delivering a service; mapping the encoded PLP data to symbols; building a signal frame based on the mapped symbols; modulating the signal frame according to an orthogonal frequency division multiplexing (OFDM) scheme; inserting a pilot symbol into a beginning part of the modulated signal frame; and transmitting the broadcast signal including the signal frame and the inserted pilot symbol. The pilot symbol comprises an effective portion, a cyclic prefix obtained by frequency-shifting a first portion of the effective portion, and a cyclic suffix obtained by frequency-shifting a second portion of the effective portion.

Abstract: Forward error correction is used in conjunction with detection of a start frame delimiter (SFD) to provide flexibility and to reduce missed instances of an SFD. Candidate SFDs in an incoming signal are identified using a lower-than-normal detection threshold, and corresponding markers are stored in a buffer. For each stored marker, a physical layer header following the candidate SFD is decoded with error-correction techniques, to determine whether uncorrectable errors exist. If so, the candidate is discarded and the next candidate is evaluated. If no uncorrectable errors exist, the candidate is declared a valid SFD, and the remaining signal is decoded. Dual detection thresholds can be employed in networks that permit both error-encoded and non-coded packets. A technique for selecting SFD patterns that facilitate higher performance is also disclosed.

Abstract: Methods and apparatuses for channel estimation are disclosed. The method includes: converting ?1's in a local Barker code to 0's; receiving a first preamble symbol output from a first Barker correlator and a second preamble symbol output from a second Barker correlator with a symbol determination module, the first preamble symbol being adjacent to the second preamble symbol; multiplying a result output from the symbol determination module with a correlation result output from the cyclic Barker correlator by using a multiplication module so as to obtain a channel estimation response; and receiving channel estimation responses with a time-domain channel data storage unit, and averaging them to obtain a noise-reduced channel estimation response. The channel estimation method and apparatus of the present invention can be achieved based on few hardware resources and low computation complexity.

Abstract: Systems, methods, and other embodiments associated with preamble detection based on repeated preamble codes are described. According to one embodiment, an apparatus is provided that wirelessly receives a signal and calculates a differential output corresponding to a multiplication of the signal and a delayed version of the signal. A cross correlation is performed between the differential output and a known preamble pattern to produce a cross correlation output. A moving average calculation is performed on the cross correlation output to produce an average cross correlation. One or more peaks are detected in the average cross correlation when the average cross correlation has an amplitude greater than a threshold. When the one or more detected peaks meets predetermined criteria, the apparatus provides information about at least one of the detected peaks for subsequent signal processing.

Abstract: The Present invention provides a correlator including, a read-out processing circuit that reads out an OFDM signal in RAM as 2n?1 number of delay OFDM signals that are increased and delayed sequentially with their adjusted read-out timings. Complex conjugate circuits that outputs complex conjugates of the inputted nth to 2n?1th delay OFDM signals. Complex arithmetic circuits that perform complex multiplication to inputted original OFDM signal, the first to n?1th delay OFDM signals, and the output signals from the complex conjugate circuits. Moving average processing circuits take the moving average of the GI length, gain adjustment circuits adjust the gains, an adder circuit adds the outputs of the adjustment circuits, and a filter circuit smoothes the addition result. A control circuit variably controls the delay of the delay OFDM signals, the gains of the gain adjustment circuits, and the band characteristic of the filter circuit.

Abstract: Discussed herein is a synchronization structure for a receiving apparatus for receiving signals in a communication system, in which the signals are transmitted in frames, each frame comprising a synchronization part with synchronization sequences, wherein at least one of the synchronization sequences has a different phase than the other synchronization sequences. The synchronization structure includes a correlation unit configured to perform a correlation on the synchronization part, a peak detection unit configured to detect candidate correlation peaks and the correlation result, and a correlation peak detection unit configured to detect a correlation peak among said candidate correlation peaks on the basis of a confidence value and phase information. Further, a corresponding synchronization method that enables frame synchronization with a higher performance in low signal to noise ratio environments is also discussed.

Abstract: The present invention relates to a method for computing correlation of a PN sequence and a circuit thereof. A plurality of input values of an input sequence is summed up to give a first sum. A PN sequence comprising a plurality of first values and a plurality of second values, which correspond to the plurality of input values, are received. Summing up the plurality of input values corresponding to the plurality of first input values in the PN sequence gives a second sum. According to the first sum and the second sum, a correlation value is given. The present invention uses a simple method for computing correlation of a PN sequence. Hence, the operation efficiency is enhanced and the time to give the correlation of the PN sequence is shortened.

Abstract: A method of estimating coarse frequency offset of received symbols based on a received frequency domain sample at a kth sub-carrier of a 53rd Orthogonal Frequency Division Multiplexing (OFDM) data symbol in a jth time slot (TS) of a receiver in a China Multimedia Mobile Broadcasting (CMMB) mobile television communication network includes dividing a received sample, Ykj, into two sets of noise only tones and data plus noise tones Dkj, obtaining a received sample only if there is a coarse frequency offset mismatch between a transmitter and the receiver, dividing a summation of a power of the data plus noise tones by a summation of a power of the noise only tones to obtain ?kj, and estimating an integer coarse frequency offset estimate, ?{circumflex over (f)}Ij, of the received symbols when the ?kj is a maximum.