Abstract: A passive phase jitter modulation (PJM) tag is charged with power in a continuous wave (CW) section. When receiving a command from a reader, the passive PJM tag must recognize the command and determine exactly when to begin demodulating the command. Only then can the passive PJM tag demodulate the command. To this end, a synchronization apparatus for accurately demodulating a signal input to a PJM tag includes a plurality of correlators correlating a received phase jitter-modulated signal with a template of an internal matched filter which is in the same form as at least a portion of a modified frequency modulation (MFM) flag.

Abstract: There are provided a receiver in human body communication system using multiple receivers reducing an error rate of receiver signals by applying a space diversity acquisition-related SIMO technology to a plurality of received data using multiple receivers or receiver electrodes in a human body communication system using a human body as a medium, and of stably transmitting the data for the interference of signals generated by other users or from different electronic devices, and a method for receiving data in the human body communication system. The receiver and the method for receiving data in a human body communication system may be useful to stably transmit/receive data without any reduction of its transmission rate by reducing the distortion in channels and the signal noise which are caused in the use of one receiver.

Abstract: According to the teachings presented herein, a method and apparatus for communication signal processing advantageously use a mix of parametric and non-parametric correlation estimation in communication signal processing. Non-parametric estimation generates an “overall” correlation estimate for a received communication signal, and parametric estimation generates a “component” correlation estimate. The component correlation estimate is removed from the overall correlation estimate to form a partial correlation estimate that is used to process the received communication signal at least initially, such as in a pre-equalization stage. The overall and component correlation estimates are generated as impairment and/or data correlation estimates.

Abstract: The invention achieves carrier and clock frequency synchronization in QAD packet communications systems. The invention involves using frequency-hopping radio systems that use pseudo-noise data sequences to mark the beginning of data transmissions and carrier frequency switches. The invention involves transmitting in each of the quadrature channels at an initial carrier frequency a first signal over consecutive time intervals and after transmitting the first signal, transmitting in each of the quadrature channels at a second carrier frequency a second signal over consecutive time intervals.

Abstract: In a wireless communication system, a portable device and an in-vehicle device wirelessly communicate with each other by a spread spectrum method. The in-vehicle device transmits a synchronization signal indicative of a reference period to the portable device. The in-vehicle device performs code acquisition for only a portion of a spread wireless signal received from the portable device. The portion has a starting point in a search period from a search start point to a search end point. The search start point is identified based on the reference period and a predetermined first correction time. The search end point is identified based on the reference period and a predetermined second correction time.

Abstract: The present invention includes a method of determining a phase estimate for an input signal having pilot symbols. The method includes receiving a plurality of pilot symbols, and then multiplying two or more pilot symbol slots by corresponding correlator coefficients to correct a phase estimate of the input signal.

Abstract: A signal processing unit and a wireless communication device are provided for making it possible to detect a frequency by means of a small scale operation circuit in a short time.

Abstract: A unique digital compression technology for increasing the information carrying capacity of a bandwidth limited communications path highway by using a combined coding and modulation technique. The inventive technology allows multiple independent modulated data streams to simultaneously and instantaneously share the same bandwidth without cross-channel interference. A matched filter is used to substantially reduce the error rate and utilizes a unique training method based on performing a spectral response test. An algorithm calculates the effect of the unique characteristics of the communications highway on the transmitted signal and generates an ideal signal stored in the matched filter for comparison with received signals.

Abstract: Described is an apparatus for suppressing spurious spectral lines in a frame based bit-serial data stream, in which frames include payload data and frame markers. The apparatus includes means (16) for randomizing first frame marker elements (START) in a first position within each frame and means (18) for correlating second frame marker elements (STOP) in a second position within each frame with the randomized first frame marker element.

Abstract: A system including a magnitude measuring module, an energy normalization module, and a metric generation module. The magnitude measuring module is configured to measure magnitudes of real portions of differentially demodulated signals, wherein the differentially demodulated signals are generated by differential demodulation of signals received from a base station. The energy normalization module is configured to generate a sum of energies of a plurality of subcarriers included in the signals received from the base station. The metric generation module is configured to generate a plurality of metrics for a plurality of symbols included in the signals received from the base station. The metric generation module is further configured to detect, based on the plurality of metrics, a preamble symbol included in the signals received from the base station.

Abstract: A permuted sequences combination uses a frame structure in which two sync words, each comprising M complex symbols, are appended at the frame start. One benefit is the reduction of the large variance of the timing estimation error in the conventional correlation method. In at least one embodiment, the first sync word, {right arrow over (s)}1, is a predetermined constant amplitude zero autocorrelation (CAZAC) sequence. The second sync word, {right arrow over (s)}2, is a permutation of the first such that the combination of the two received sync signal vectors perform sliding window processing where the peak occurs at the correct frame start. The permuted sequences combination can be used in both AWGN channel and multi-path environments.

Abstract: A sync detection device and method for a GNSS receiver. In modernized GNSS, each satellite transmits a data signal and a pilot signal. Correlations are performed between a data symbol stream converted from the data signal with possible hypotheses to find a leading edge of a frame of the data signal (i.e. frame sync detection) and between a pilot symbol stream converted from the pilot signal with possible hypotheses to find a leading edge of a code sequence of the pilot signal (i.e. pilot sync detection). The possible hypotheses for the frame sync detection are selected according to a result of pilot sync detection when pilot sync is done. Frame sync can be efficiently achieved since a range of the selected possible hypotheses is quite limited.

Abstract: A method for performing carrier frequency offset estimation and frame synchronization is disclosed herein. In one approach, the method includes performing a first level frequency discrimination on at least one estimated channel tap to generate a frequency discriminated value; estimating a phase error from the frequency discriminated value; and, determining a predetermined frame synchronization pattern from the estimated phase error. A computer program product having code and a wireless communications apparatus for performing the method are also described herein.

Abstract: Methods and systems for processing a Global Positioning System (GPS) signal are provided. A method includes: transforming a time domain GPS signal to a frequency domain GPS signal; storing a frequency domain pseudorandom noise (PRN) signal; correlating the frequency domain GPS signal with the PRN signal at a plurality of frequencies, said correlating including: shifting the frequency domain GPS signal by an amount corresponding to one of the plurality of frequencies; downsampling the shifted frequency domain GPS signal; and multiplying the shifted frequency domain GPS signal by the stored frequency domain PRN signal to produce a correlated signal.

Abstract: The present invention provides methods and systems for allowing a receiver in a (wireless) communication system to synchronize its timing and frequency subsystems in accordance with a received signal. In accordance with one aspect, a method is provided in which a relative time of arrival of sync values provided in a received signal are determined and used to align the receiver's reference signal(s) accordingly. Other aspects of the invention will become apparent from the detailed description of exemplary embodiments that follows.

Abstract: Provided is a high frequency radio apparatus for correcting a frequency of a carrier of the own apparatus in accordance with a frequency of a reception carrier when performing spread spectrum communication using very weak power. A carrier demodulating part demodulates a spread code received from a communication counterpart radio apparatus by using default carrier data, and sends the demodulated spread code to a synchronization timing detecting part. When the synchronization timing detecting part detects the spread code from the carrier demodulated data, a carrier frequency deviation detecting part performs a frequency analysis of the spread code to detect a deviation amount of the carrier frequency. A carrier data generating part generates corrected carrier data based on the detected deviation amount. A DBPSK modulating part uses the corrected carrier data to perform data transmission to the communication counterpart radio apparatus.

Abstract: Methods and systems for digital control utilizing oversampling.

Abstract: A secure information transmission system includes one or more transmitters and one or more receivers. The transmission waveform employed includes highly randomized, independent stochastic processes, and is secured as a separate entity from the information it carries. The signal, using novel modulation methodology reducing impulse responses, has a paucity of spectral information and may be detected, acquired and demodulated only by communicants generating the necessary receiving algorithm coefficients. The physical area of signal reception is restricted to that of each intended communicant, reception areas following movements of mobile communicants. A unique instant in time is used as basis for communications keys to the securing algorithms dynamically generated on a one-time basis and never exchanged or stored by communicants.

Abstract: A feedback loop is used to determine phase distortion created in a signal by directly extracting the phase distortion information from a feedback signal using original frequency modulation information.

Abstract: Disclosed is a signal processing method and apparatus in MIMO system. In a mobile communication system having a plurality of transmitting antennas, the present invention includes the steps of receiving a feedback signal including status information of at least one channel, segmenting one of the first data blocks to segment into at least one or more of the second data blocks, attaching a CRC to each of the at least one or more of the second data blocks, allocating the at least one or more second data blocks to a plurality of the transmitting antennas, respectively, and transmitting the at least one or more of the second data blocks. In a mobile communication system having a plurality of receiving antennas, the present invention includes the steps of receiving at least one data block including a CRC or dummy bits, acquiring channel status information using the CRC or dummy bits, and transmitting the channel status information.

Abstract: The present invention provides a method of coordinating transmission by and reception by a plurality of antennas associated with a plurality of radio heads. The method includes determining, at a controller, at least one relative time delay associated with a plurality of backhaul links between the controller and the plurality of radio heads. The method also includes providing information indicative of a first signal over the plurality of backhaul links. The method further includes providing timing information over the plurality of backhaul links. The timing information is determined based on the relative time delay(s) such that the plurality of radio heads can use the provided timing information to coherently transmit the first signal using the plurality of antennas and a plurality of controllers to receive mobile unit transmitted information.

Abstract: The present invention relates to a method of validating the detection of a correlation peak between a signal transmitted by a plurality of navigation satellites and received by an RNSS satellite radio navigation receiver, said signal corresponding to a sum of signals each sent by a satellite and each modulated by a spread spectrum signal characteristic of said satellite and a local replica generated by said receiver of a spread spectrum signal characteristic of a satellite that is being looked for. Said method includes a step of determining the correlation function 3 as a function of time between said received signal and said local replica and further includes a step of comparing said correlation function 3 with the theoretical autocorrelation function 2 as a function of time of said spread spectrum signal characteristic of said satellite that is being looked for.

Abstract: A system for implementing an orthogonal frequency division multiplexing scheme and providing an improved range extension. The system includes a transmitter for transmitting data to a receiver. The transmitter includes a symbol mapper for generating a symbol for each of a plurality of subcarriers and a spreading module for spreading out the symbol on each of the plurality of subcarriers by using a direct sequence spread spectrum. The symbol on each of the plurality of subcarriers is spread by multiplying the symbol by predefined length sequences. The receiver includes a de-spreader module for de-spreading the symbols on each of the plurality of subcarriers. The de-spreader module includes a simply correlator receiver for obtaining maximum detection. The correlator produces an output sequence of a same length as an input sequence and the de-spreader module uses a point of maximum correlation on the output sequence to obtain a recovered symbol.

Abstract: A system includes an input, a differential demodulation module, a magnitude measuring module, a summing module, and a metric generator module. The input receives input signals that include s sets of modulated sub-carriers carrying symbols, where s is an integer greater than or equal to 1. The differential demodulation module generates differentially demodulated signals based on the input signals. The magnitude measuring module measures magnitudes of real portions of the differentially demodulated signals. The summing module generates s sums, wherein each of the s sums is a sum of the magnitudes generated based on a respective one of the s sets. The metric generator module generates metrics for the symbols based on the s sums.

Abstract: A technique for reducing crosstalk between communications paths includes scrambling data using scrambling functions that reduce or substantially minimize a probability that worst-case data patterns occur on communications paths adjacent to a potential victim communications path. In at least one embodiment of the invention, a method includes scrambling a plurality of data bits based at least in part on respective ones of a plurality of distinct combinations of one or more taps of a linear feedback shift register (LFSR). The plurality of data bits are scrambled for transmission during a first bit-time on corresponding ones of a plurality of adjacent communications paths.

Abstract: Methods and apparatus for reduction of a peak to average ratio for an OFDM transmit signal. In an aspect, a method is provided for reducing a peak to average ratio of a transmit waveform. The method includes obtaining a primary scrambler sequence, generating a secondary scrambler sequence having a length characteristic based on data to be scrambled, and combining the primary and secondary scrambler sequences to produce a PAR reduction sequence. In another aspect, an apparatus is provided for reducing a peak to average ratio of a transmit waveform. The apparatus includes a secondary generator configured to generate a secondary scrambler sequence having a length characteristic based on data to be scrambled, and combining logic configured to combine a primary scrambler sequence and the secondary scrambler sequences to produce a PAR reduction sequence.

Abstract: A method and system is provided for detecting preambles in a multi-cell communication system. The method detects preambles reliably even in the presence of interference caused by multiple cells reusing the same frequency in the multi-cell communication system. After receiving a signal in the receiving period, the time domain signal is sampled and transformed into the frequency domain vector. The correlation vector is calculated with the frequency domain vector and pseudonoise code of the wireless station. The presence of a preamble is verified if the value in the correlation vector exceeds a predetermined threshold.

Abstract: The present invention provides architectures and methods which enables faster and more power efficient detection of channel parameters used by a communication system. Various parallel preamble correlator structures are able to perform searches for multiple preambles in parallel. The received samples are correlated with different delays between the samples corresponding to the different possible channel parameters that may be used by the communication system. Processing elements used in the preamble search may be shared among the parallel preamble search sections of a given architecture to reduce costs and power consumption. Decimation and filtering may also be used to reduce the interference from adjacent channels.

Abstract: A variable code-tracking loop filter in a receiver having the ability to change its parameters multiple times in response to received signals. Parameters for the code-tracking loop filter may be varied based on phase and frequency errors from an error detector. In one implementation, the code-tracking loop filter is able to repeatedly vary a single parameter, such as its received bandwidth, based on the phase and frequency errors, while in another, the code-tracking loop filter may vary two or more parameters, such as the loop bandwidth and the natural frequency.

Abstract: Provided is a synchronization error tracking device and method. The method and system estimates and corrects the synchronization error generated by time and frequency offsets during the data transmission interval and uses a module designed for initial synchronization or channel estimation without adding a new correlation operator. Further, a combining mark value and a synchronization position value acquired during the synchronization process are used.

Abstract: A secure information transmission system includes one or more transmitters and one or more receivers. The transmission waveform employed includes highly randomized, independent stochastic processes, and is secured as a separate entity from the information it carries. The signal, using novel modulation methodology reducing impulse responses, has a paucity of spectral information and may be detected, acquired and demodulated only by communicants generating the necessary receiving algorithm coefficients. The physical area of signal reception is restricted to that of each intended communicant, reception areas following movements of mobile communicants. A unique instant in time is used as basis for communications keys to the securing algorithms dynamically generated on a one-time basis and never exchanged or stored by communicants.

Abstract: Embodiments provide systems and methods for improved multiple-input, multiple-output (MIMO) detection comprising generating at least one list of candidate vectors by employing lattice enumeration which approximates hyperellipsoid detection search space and calculating a reliability of the candidate vectors. At least one advantage to embodiments is that improved detection occurs because detection can be performed in a search space defined by the eigenvectors (which define the general shape of an ellipsoid/hyperellipsoid, depending upon number of dimensions) and eigenvalues (which provide the appropriate scaling in each direction of the eigenvectors) of the effective channel.

Abstract: A signal detection device rapidly and accurately detects a desired signal from a reception signal. A correlation unit 231 outputs a correlation value string obtained by cross-correlating an input symbol string and a reference symbol string, a first position detection unit 232 detects a position of a correlation value viewed as a maximum or a local maximum on the correlation value string, a compensation unit 233 performs compensation by suppressing correlation error values from correlation value at positions other than the detected position, a second position detection unit 234 detects a position of a correlation value viewed as the maximum on the compensated correlation value string, and a sync-detected signal generation unit 235 outputs a sync-detected signal based on the position detected by the second position detection unit 234.

Abstract: A method is disclosed, including identifying a preamble in a frame, where the preamble has a preamble length 1. M data items received in succession are stored. The m data items once divided into n portions, where the data items in each portion have respectively been received at successive times and where m and n are natural numbers and the following applies to m and n: m>n, m>1, n>1. The n portions are respectively correlated to the expected values to form component correlation results. Delaying the component correlation results, with at least two component correlation results being delayed by different lengths. The method also includes combining the delayed component correlation results to form a total correlation value. The total correlation value is used to determine whether the m received data items contain the preamble of a frame.

Abstract: A single chip diversity beamforming antenna array processor is disclosed. The processor utilizes low-power and low area circuits to achieve combining game mitigate the effects of multipath fading provide spatial suppression and provide diversity gain to a single input receiver. The device is radiofrequency transparent yet provides antenna gain by selective three G and four G code acquisition and tracking of a desired downlink channel.

Abstract: Receiver and reception method of receiving pulsed ultrawideband radio-frequency signals employ an amplification phase, an oscillation phase sensitive to an instability control signal, a shaping phase, and a demodulation phase, and further including an adaptation control step for adapting the receiver or the reception method to the type of signals to be received.

Abstract: The present invention relates to a method for measuring radio channel quality in a radio communication system. In the method a modulated signal is received over a communication channel. The modulated signal has been modulated by using modulation parameters. A decoder decodes (305) the modulated signal and forms decoded data. The decoder creates (306) a decoder performance indicator (PS) that depends on the decoded data. Then a radio channel quality indicator (RCQI) is created, the radio channel quality indicator being essentially independent of the modulation parameters.

Abstract: A highly concealable data communication apparatus based on an astronomical complexity and causing an eavesdropper to take a significantly increased time to analyze a cipher text, is provided. In a multi-level code generation section 111a, a random number sequence generation section 141 generates, based on predetermined key information 11, a plurality of modulation pseudo-random number sequences. The plurality of modulation pseudo-random number sequences is inputted to a multi-level conversion section 142 as a part of an input bit sequence which is converted into a multi-level code sequence 12. A multi-level processing section 111b combines the multi-level code sequence 12 and information data 10, and generates a multi-level signal 13 having a plurality of levels corresponding to a combination of the multi-level code sequence 12 and the information data 10.

Abstract: A method is provided for frequency acquisition, particularly for initial frequency acquisition, pursuant to a known synchronization sequence for synchronizing a mobile communications device having a local oscillator with previously known transmit frequencies of a base station that transmit in a known channel raster with defined frequency points within a band, wherein the method includes the steps of determining the inband power of the known synchronization sequence via a sensor by scanning a frequency band, performing coarse determination of the local power maximum of the inband power and, thus, of the received carrier frequency over the scanned frequency band, producing a presumed channel frequency at which the base station is transmitting on the basis of knowledge of the channel raster of the transmit frequencies of the base station, performing fine determination of the received carrier frequency by comparison with the known synchronization sequence, and correcting the frequency deviation of the local oscil

Abstract: A digital communication system includes a generator for generating a plurality of pulse trains, each having a different timing, and pre-compensation circuitry for synchronizing the plurality of pulse trains to a timing signal. The system also includes comparison circuitry for simultaneously comparing a received burst code signal to each of the plurality of pulse trains, where the burst code signal is synchronized to the timing signal, and a detector for detecting which of the pulse trains is a closest temporal match to the burst code signal. The pre-compensation circuitry operates to reduce acquisition time and keep PN code uncertainties within the range of the comparison circuitry.

Abstract: An apparatus and method for adjusting transmission phasing in a point-to-point communication link is disclosed. The relative phases of the transmissions from each antenna are adjusted before transmission to give optimum gain when received by two or more antenna elements and a signal combining element. The signal includes a data component, consisting of a subset of the subcarriers modulated with the input data, which is common to transmissions from all antenna elements; and a phase reference component consisting of a subset of the subcarriers that are modulated with a predetermined phase. The signal combining element is operable to receive the components and extract phase information.

Abstract: An integrated circuit includes first, second and third circuits, a clock module and a rate adapting module. The first circuit causes frequency dependent noise and is clocked based on a clock signal. The second circuit is rate dependent and is clocked based on an operation dependent clock signal. The third circuit is susceptible to adverse performance when the frequency dependent noise has a component within a given frequency range. The clock module generates a clock signal having a rate such that frequency dependent noise components associated with the clock signal are outside the given frequency range. The rate adapting module is coupled to produce the operation dependent clock signal from the clock signal.

Abstract: A communication system for pulse based communication using a sequence acquisition system using the correlation method in UWB communications which generates a pulse detection signal differing in phase by exactly a predetermined period (?) from the transmission information of a pulse signal of a predetermined period at the transmission side and reception side, uses the pulse detection signal to establish synchronization at the reception side, then generates transmission information at the reception side by making its phase different by exactly a predetermined time from the synchronized pulse detection signal so as to establish synchronization between the reception signal and the transmission information, whereby it is possible to enable synchronization acquisition and shorten the synchronization acquisition time without complicating the hardware and even without the presence of information in the transmission signal.

Abstract: A synchronization timing detecting apparatus includes a correlation calculator configured to generate a first correlation value by calculating a cross-correlation between an input signal being sampled and a reference signal or an auto-correlation of the sampled input signal, an interpolation processor configured to generate a second correlation value interpolating a plurality of the first correlation values having a different combination of sampling points of the input signal, and a detector to detect a synchronization timing based on the first and the second correlation values.

Abstract: A receiver includes a baseband processor for selecting a set of demodulation processing delays for received signal demodulation from a larger set of candidate delays. In one embodiment, the baseband processor selects the set of demodulation processing delays by calculating at least one metric for each demodulation processing delay in the set of candidate delays, iteratively reducing the set of candidate delays by eliminating one or more demodulation processing delays from the set as a function of comparing the metrics, and setting the processing delays for received signal demodulation to the candidate delays remaining after reduction. In a Generalized RAKE (G-RAKE) embodiment, the metric corresponds to combining weight magnitudes associated with G-RAKE finger delays. In a chip equalizer embodiment, the metric corresponds to coefficient magnitudes associated with equalization filter tap delays.

Abstract: Channel and correlation characteristics are determined for a composite signal. Respective combining weights for information from the composite signal are determined for respective ones of a plurality of candidate delays based on the determined channel and correlation characteristics. A group of delays, e.g., RAKE correlator delays or chip equalizer filter taps, is selected from the plurality of candidate delays based on the determined weights. Information from the composite signal for the selected delays is processed according to a spreading code to generate a symbol estimate. The invention may be embodied as methods, apparatus and computer program products.

Abstract: An apparatus for determining the amount of skew to be injected into a high-speed data communications system of including a plurality of lanes having a data bus per lane, relative to a reference lane, for system skew compensation. By knowing the relative amount of skew that each lane requires for alignment, an appropriate amount of skew can be injected on each lane to provide alignment and thus compliancy with the SFI-5 and SxI-5 standards, in terms of data skew specifications. The relative skew amounts for each transmitting lane are determined using a methodology involving internal loopback and characteristics from a connected communications element to the chip receive path.

Abstract: A generator of repetitive sets of spreading sequences includes an element for counting and for forming an address and a table containing L sets of S sequences. The address contains q+log2S bits. The q bits are used for selecting one set among L (L=2q) sets. The log2S bits are used for selecting one sequence among the S sequences in the set.

Abstract: A wireless communication apparatus includes: a transmitter which sends transmitted data while mixing it with a carrier; a receiver which receives the transmitted data sent from the transmitter while mixing it with the carrier; a spreading waveform generator which generates a spread clock resulting from a reference clock for generating the carrier being spread in a PN pattern; a wired sender which, by sending the spread clock by wire, causes both the transmitter and the receiver to share it; and a carrier reproducer which reproduces the carrier based on a result of a phase comparison with the spread clock.

Abstract: A synchronism pattern detecting timing recorder (20) records a synchronism pattern detecting timing at which a synchronism pattern is detected in reception data, a synchronism decider (12) collates the reception data with reference data to decide whether or not the reception data is consistent in phase with the reference data, and a timing generator (22) operates, when the synchronism decider (12) gives a decision for inconsistency in phase, for a match between the synchronism pattern detecting timing recorded in the synchronism pattern detecting timing recorder (20), as a subsequent one, and a timing of a synchronism pattern of the expectation data, and the subsequent synchronism pattern detecting timing in record is used to render the phases consistent, allowing for a rapid synchronization to be obtained, without the need of waiting a detection of synchronism pattern, even with an inconsistency in phase due to a false synchronism pattern.