Abstract: A method is provided for receiving a multicarrier signal formed by a temporal succession of symbols including of a set of data elements with real values, including informative data elements and pilots. Due to at least one preamble being inserted into the multicarrier signal and formed by at least two end symbols, encompassing at least one central symbol including of central pilots, such a reception method includes, for at least one central pilot, a step of eliminating or reducing an interference affecting the central pilot, and a step of estimating the transmission channel, taking into account the result of the eliminating or reducing step.

Abstract: Apparatus for recovering symbols from control and data channels corresponding to a plurality of users is described. Samples corresponding to control channel signals from multiple users are processed on a time shared basis with various control channel processing elements being reused multiple times to processes the samples and recover signals, e.g., symbols, corresponding to the plurality of users. While the control channel processing elements are used on a time shared basis, a separate data channel processing chain or module maybe provided for each of the plurality of users. In some embodiments the order of despreading and filtering is reversed for the control and data channel signal processing.

Abstract: A frequency tracking method applied to a positioning system is provided. The method includes receiving a baseband signal, the baseband signal includes a line of sight (LOS) signal and a multipath signal; generating a cost function according to equal step frequencies, the baseband signal and a signal average energy; and generating an estimated LOS frequency according to the cost function.

Abstract: In one exemplary embodiment of the invention, a device includes: a first frequency search engine configured to receive input values and determine a frequency of a signal to be within a first frequency band; a second delay component configured to store at least a portion of the plurality of input values; and a second frequency search engine configured to determine the frequency of the signal to be within a second band that is a subset of the first band. The first frequency search engine includes: a shift register configured to store bits of the input values; a combining circuit configured to combine bits of the plurality of input values; a first delay component configured to serially store a plurality of accumulator values; and a feedback circuit configured to add a function of the first delay component output to a next accumulator value to obtain a modified next accumulator value.

Abstract: The present invention discloses a transmitted/received data decoding method and apparatus, which achieve effects of decoding performance improvement and synchronous detection. The decoding method includes setting a coded edge pattern, and filtering a received data by using the set coded edge pattern as a window; respectively computing absolute values of filtered values filtered by using the coded edge pattern windows; detecting a maximum absolute value from the computed absolute values; determining a sign (+/?) for the detected maximum absolute value; outputting an intermediate bit value of the corresponding original data as a resultant decoded value according to the determined sign and a window type (i.e. coded edge patter) with the selected maximum absolute value.

Abstract: Sub-microsecond time transfer in a GPS/GNSS receiver using a weak GPS/GNSS signal is provided. The digitized complex baseband signal and the generated PN code are cross-correlated for each code period so as to output a complex correlation value at each code epoch of the generated PN code, where a sequence of the output correlation values form a data stream representing the navigation message. Bit synchronization generates bit sync pulses at bit boundaries. The location of a target segment having a known sequence at a known bit location in the navigation message is detected by searching through a plurality of sub-frames and accumulating search results for the plurality of subframes. Transmission time of the target segment is determined from the detected location of the target segment, with a certain time ambiguity. Accurate local time is determined by solving the time ambiguity using approximate time obtained from an external source.

Abstract: A low-cost GPS/GNSS receiver receives a satellite signal at an RF frequency (fRF). The GPS/GNSS receiver includes a front end section for receiving the satellite signal and generating a digital complex signal having a first bandwidth, the received satellite signal being converted into a complex signal before digitizing, a signal capturing section for searching for and acquiring the satellite signal, the signal capturing section including a capture memory, a baseband processor for tracking the acquired satellite signal, and a signal splitter coupled to the front end section. The signal splitter splits the digital complex signal into two bandwidths, by generating a narrowband digital complex signal having a second bandwidth substantially smaller than the first bandwidth. The signal splitter provides the narrowband digital signal to the capture memory and the wider first bandwidth digital complex signal to the baseband processor.

Abstract: Disclosed herein is a receiving apparatus including a first correlation value computation section, an operation section, a second correlation value computation section, a decoding section, and a determination section.

Abstract: A method can include receiving, at an electronic transmitter device, for communication to an electronic receiver device, a first data value corresponding to one of a plurality of predetermined data values; identifying, from a matrix of data bits having the form of a 2N×2N Hadamard matrix whose rows have been randomly or pseudo-randomly shuffled, a column of data bits that is associated with the first data value; and transmitting to the electronic receiver device, in place of the first data value, the identified column of data bits. The method can further include receiving data at the electronic receiver; correlating the received data to the identified column of data bits; and providing the first data value for further processing by the electronic receiver.

Abstract: A method and apparatus for use in connection with wireless communication to adjust the frequency of an oscillator to synchronize with a received signal by correlating a synchronization code channel with training sequences to estimate relative offsets which are employed to estimate an error, which is then filtered. The filtered output preferably provides a voltage controlling a voltage controlled oscillator (VCO). The same technique may be employed to control a numeric controlled oscillator (NCO).

Abstract: A simple and robust CTL is used for time tracking of multipath components of a spread spectrum signal transmitted over a wireless multipath fading channel. A digital code-tracking loop includes the implementations of despreading early and late data samples by use of a pseudonoise sequence, an error signal output generated by the despreading, and adjustment for a plurality of on-time, early and late samples, a data rate of a control signal provided as a fractional proportion of a data rate of error signals.

Abstract: A wireless receiver receives a signal obtained by multiplexing a plurality of signals that include a synchronization signal that is spread using a non-orthogonal code not orthogonal to a code for spreading other signals other than the synchronization signal. Then, in a case when the signals other than the synchronization signal are the target signals for decoding, the wireless receiver performs despreading with respect to the received signal using the synchronization signal and estimates the signal amplitude of the non-orthogonal code. Subsequently, the wireless receiver eliminates the spread synchronization signal from the received signal using the estimated signal amplitude of the non-orthogonal code and using the synchronization signal. Eventually, the wireless receiver performs despreading and demodulation with respect to the signal having the spread synchronization signal eliminated therefrom and decodes the target signals for decoding.

Abstract: Provided are a high-speed Discrete Fourier Transform (DFT) apparatus and a method thereof. The high-speed DFT apparatus includes a zero padding unit, a Fast Fourier Transform (FFT) unit, and a preamble index decision unit. The zero padding unit receives a first input signal having a length of a prime number and changes the first input signal into a second input signal having a length of an exponentiation of 2. The FFT unit performs a FFT on the second input signal outputted from the zero padding unit. The preamble index decision unit detects a preamble index from an output signal from the FFT unit.

Abstract: A method for the generation of a signal including a minimum of disturbances and noise is provided. A method for the detection of a signal including a minimum of disturbances and noise is also provided. An element of the signal is functionally dependent on at least one further element of the signal.

Abstract: A system for transmitting quantum information includes a sending unit including an encoder configured to encode a carrier with quantum information by setting a quantum state of the carrier, the quantum state determined according to the combination of a first component and a second component, and a receiving unit including a decoder configured to perform a measurement on the carrier using a measurement basis selected to cancel the second component and decode the quantum information from the carrier.

Abstract: Embodiments of the invention provide for allocating spectrum in a wireless communication system that supports simultaneously at least a first mode of operation and a second mode of operation. Logic is arranged for determining a proportion of spectrum required for the wireless communication unit to operate simultaneously in both the first mode of operation and the second mode of operation. Logic for allocating spectrum allocates a temporary guard band between a first portion of spectrum for the first mode of operation and a second portion of spectrum for the second mode of operation for use while the wireless communication unit operates simultaneously in the first mode of operation and second mode of operation.

Abstract: A receiver includes a receiving unit that receives a signal from a satellite, a frequency conversion-discretization unit that converts the signal received in the receiving unit into an intermediate frequency signal of a frequency bandwidth including 0 Hz, and discretizes the frequency-converted intermediate frequency signal with a predetermined sampling frequency, a filter unit that filters the discretized signal, which is output from the frequency conversion-discretization unit, through a predetermined filter, a synchronization acquisition unit that acquires synchronization of a spreading code in the discretized signal filtered by the filter unit, and a synchronization holding unit that holds the synchronization of the spreading code, which is acquired by the synchronization acquisition unit.

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: The present invention relates to an ultra-wideband signal receiver comprising: at least a first set of sampling cells for sampling the waveform of a received signal; at least a second set of sampling cells for sampling the waveform of the received signal, with a predefined delay ?; and at least one correlator for delivering information depending on the correlation between the waveforms thus sampled.

Abstract: A codebook, a codebook creating method, and an uplink transmission method and equipment based on the codebook relating to per-coding in telecommunication are provided. In the method, a codebook size and a symbol set are determined. A minimum distance is calculated. A maximum codebook is selected according to the minimum distance. The method is used in per-coding of uplink transmission to reduce power loss of an uplink power amplifier.

Abstract: A correlation apparatus and method for frequency synchronization are provided. A frequency synchronization method of a receiver in a broadband wireless access communication system includes acquiring a highest correlation value by conducting a differential correlation of a variable interval between a received signal and a reference signal and performing a frequency synchronization according to the highest correlation value.

Abstract: A signal processing system is provided. The system includes a calculating apparatus, for calculating a phase error of a received signal and generating a weight according to the phase error; a signal adjusting apparatus, coupled to the calculating apparatus, for generating a plurality of soft values according to the weight and the received signal; and a decoder, coupled to the signal adjusting apparatus, for decoding the soft values to generate data.

Abstract: A code sequence transmission method capable of improving system throughput and user throughput by improving power utilization efficiencies of a control channel and a data channel including a plurality of signals having different required qualities is provided. In a mobile station, a bit sequence of a TFCI is transmitted within one frame a plurality of times repeatedly, the bit sequence of each TFCI is multiplied by one bit of a bit sequence of an SI, a multiplication result is transmitted. It is thereby possible to transmit both the TFCI and the SI without providing a signal field of the SI in each frame.

Abstract: Provided are a method for dynamically acquiring a PN synchronization of a blink signal in a reader according to a channel state when a tag transmits a direct sequence spread spectrum (DSSS) blink signal having a predetermined period and the reader receives the blink signal in a 2.4 GHz RTLS system which complies with an ISO/IEC24730-2 standard, and a method for synchronizing a frame using a preamble.

Abstract: Systems (100) and methods (700) for processing a data signal in a communications system. The methods involve generating a first chaotic sequence at a transmitter (102). The methods also involve performing first basis function algorithms using the first chaotic sequence to generate first statistically orthogonal chaotic sequences. At least one sequence is selected from the first statistically orthogonal chaotic sequences for combining with a first data signal. The selected sequence is combined with a second data signal to obtain a modulated chaotic communication signal. The modulated chaotic communication signal is transmitted to a receiver (104). At the receiver, the received modulated chaotic communication signal is processed to obtain data therefrom. Notably, the signal processing generally involves performing a deterministic process (e.g., a Hidden Markov Model deterministic process).

Abstract: A method is provided for receiving a received signal corresponding to a multicarrier signal transmitted by at least one transmitter via a transmission channel, the multicarrier signal being formed by a temporal succession of symbols including of a set of data elements with real values, including informative data elements, and reference data elements called pilots for at least some of the symbols. The reception method includes step of first estimation of the transmission channel. Due to at least one of the pilots being an isolated pilot in transmission, the reception method further includes a step of extracting the isolated pilot, and a step of locally refining the first estimation.

Abstract: A cell search method and apparatus for an asynchronous mobile communication system are provided. A Secondary Synchronization Code (SSC) correlator despreads a signal at every slot boundary in accordance with a z-sequence to output a SSC correlation value. The signal is received over a first symbol duration. A Primary Synchronization Code (PSC) correlator despreads the received signal in accordance with a PSC to output a PSC correlation value. A dot product calculator performs dot product calculation between the SSC correlation value and the PSC correlation value to output a correlation result of the SSC. A frame synchronization detector extracts frame synchronization information from the correlation result.

Abstract: Embodiments of methods and apparatus for wirelessly communicating signals include one or more transmitters configured to generate a plurality of wireless signal for transmission. Each of the wireless signals includes a plurality of pilot signals represented in a plurality of unevenly spaced, in-band subcarriers. Pilot signals of each wireless signal are positioned at subcarriers that are orthogonal in frequency with subcarriers at which pilot signals of all other wireless signals are positioned. According to an embodiment, subcarrier indices each the plurality of pilot signals are determined using a third order or higher order polynomial parameterization of pilot subcarriers in conjunction with a convex optimization algorithm to produce pilot signals having near-optimal channel estimate mean square error (MSE) performance. The wireless signals are simultaneously radiated over a wireless communication channel using a plurality of co-located or distributed antennas.

Abstract: An embodiment for wirelessly communicating a signal includes a transmitter combining a plurality of phase shifted input data signals with a plurality of synchronization/pilot sequences to produce a plurality of combined signals, performing frequency domain-to-time domain transformations of the combined signals to produce a plurality of candidate signals, determining peak-to-average ratios for at least some of the plurality of candidate signals, identifying a selected signal from the plurality of candidate signals based on the peak-to-average ratios, and transmitting the selected signal over a wireless communication channel.

Abstract: An acquisition module includes a coherent correlator configured to receive a transmission having a pilot signal and correlate the received transmission with a local copy of the pilot signal to produce a first output, a delayed correlator configured to delay the first output and correlate the first output with the delayed first output to produce a second output, and a detector configured to detect the pilot signal in the transmission based on the second output.

Abstract: Disclosed are a frame synchronization method and a receiver for a communication modem using the same. The frame synchronization method includes performing a correlation operation between a reception data stream and a preamble to output a synchronous signal; and computing correlation values between spreading codes and a reception data stream synchronized with the synchronous signal, wherein a maximum value of the computed correlation values is compared with a preset threshold value, and the outputting of the synchronous signal is performed again when the maximum value is smaller than the preset threshold value.

Abstract: A high sensitivity GPS receiver includes an acquisition engine and a tracking engine. The acquisition engine processes GPS satellite data at data rate that is substantially equal to twice the coarse acquisition (CA) code chip rate. This data rate advantageously enables the acquisition engine to process GPS satellite data with relatively less hardware area than traditional GPS acquisition approaches. In one embodiment, the high efficiency acquisition engine may be over-clocked, thereby allowing different phases of a CA code to be correlated quickly. The tracking engine can advantageously process GPS satellite data at a data rate that does not have an integer relationship to the CA code chip rate.

Abstract: An interference detector receives a data stream including predetermined symbols that include a first data and a second data, between which is a frequency offset. The interference detector includes a correlation apparatus that generates a first correlation result and a second correlation result according to the data stream; a power searching unit, coupled to the correlation apparatus, that generates a first maximum correlation result and a first neighboring power according to the first correlation result, and generates a second maximum correlation result and a second neighboring power according to the second correlation result; and a determining unit, coupled to the power searching unit, that generates a determination result according to the first maximum correlation result, the first neighboring power, the second maximum correlation result and the second neighboring power to indicate existence of interferences.

Abstract: A signature sequence employed in a wireless transmission over a channel is detected and utilized. The signature sequence is selected from a set of sequences formed by delay-Doppler shifts of a base sequence. Preferably but not exclusively, the set of sequences is formed by circular delay-Doppler shifts of the base sequence. The base sequence can be, for example, an m-sequence. A received signal is obtained from a received wireless transmission. A candidate sequence selector (90) selects a candidate sequence from among a set of sequences for evaluation as the signature sequence, the set of sequences having been formed by sequence set generator (88) as delay-Doppler shifts of a base sequence. An image former (82) uses the base sequence and the received signal to form a delay-Doppler image with respect to an image area pertinent to the candidate sequence.

Abstract: In this invention, a channel estimation value of data symbols of a data channel is calculated by weighting and averaging pilot symbols in a parallel time multiplexing method. Also, a channel estimation value of data symbols during each data symbol interval is calculated by dividing data symbols in a slot into a plurality of data symbol intervals, selecting pilot symbols suitable for calculation of a channel estimation value of data symbols during each data symbol interval and weighting and averaging that pilot symbols. Also, a fading frequency is detected based on an inner product value of pilot symbols. Weighting factors are changed based on the detected fading frequency. Also, a channel estimation value is calculated by weighting and averaging pilot signals using a plurality of weighting sequences. The calculated channel estimation value is used to demodulate received data. The output data with the highest quality is selected by judging reliability of these plurality of demodulated data.

Abstract: A code phase signalling module arranged to provide code phase signalling to assist in signal acquisition of direct sequence spread spectrum signalling received by a receiver module from a transmitter module. The code phase signalling is arranged to be used by the receiver module to synchronise the phase of a synchronisation code provided from within the receiver module with the phase of a modulation code of the direct spread spectrum sequence signalling received by the receiver module. The synchronisation code sequence corresponds to the modulation code sequence. The code phase signaling module is arranged to provide code phase time signaling representing the offset time of the synchronisation code from a reference time. The reference time is associated with the time of transmission of a particular reference portion of the modulation code of the direct spread spectrum signaling.

Abstract: The disclosed is a method for synchronization of the running key that is generated from a shared key and that is used for encryption and decryption in communications encrypted with the shared key using a multi-valued signal. In the method for synchronization, the transmitting node transmits a signal that is formed of a multi-valued signal and that has a predetermined fixed pattern before transmitting data encrypted with the shared key. The receiving node generates a bit discrimination threshold signal that allows for bit discrimination and that has a fixed length, shifts bit by bit the phase of the bit discrimination threshold signal while monitoring bit discrimination with respect to a fixed pattern signal that is to be received, and sets the phase of the bit discrimination threshold signal when the phase of the fixed pattern signal matches the phase of the bit discrimination threshold signal.

Abstract: Apparatus and methods of implementing code space search of received signals are described herein. A code space search is implemented as a searcher that perform a subtask that is dynamically reconfigurable at each boundary of an initial integration time. Each particular subtask sets forth a programmable configuration of coherent integration hypothesis that are performed during the initial integration time. The searcher stores the results of the coherent integration hypothesis in a first portion of memory. A search accelerator operates on the initial integration results. The search accelerator can perform coherent integration of various frequency bins of different timing hypothesis, can generate energy values of the coherent integration results, and can generate a non-coherent energy summation. The energy values of the coherent integrations and non-coherent energy summations are stored in a second portion of memory.

Abstract: A CDMA receiving apparatus includes a path searcher which outputs path timing that corresponds to sample timing where a correlation value between a received data sequence and a reference code sequence reaches a peak, and outputs the correlation value calculated at a sample timing adjacent to the path timing as an adjacent timing correlation value; an interpolation adjuster; and a despreader which despreads an output of the interpolation adjuster at the path timing, wherein the interpolation adjuster includes an interpolator for generating an interpolating data sequence which is a data sequence displaced in time by a specified fraction of one sample period with respect to the received data sequence, and outputs the received data sequence or the interpolating data sequence by switching therebetween based on a result of a comparison between the correlation value calculated at the path timing and the adjacent timing correlation value.

Abstract: In one embodiment, a method includes generating a set of sequences of chip values and calculating a correlation between a demodulated signal and each one of two or more of the sequences. Each of the correlations has an absolute value, and one of the correlations has a highest absolute value. The method includes selecting the one of the sequences with the correlation having the highest absolute value; identifying a sequence index corresponding to the selected one of the sequences; and, for each of one or more data symbols in the demodulated signal, determining a value of the data symbol based on the sequence index corresponding to the selected one of the sequences.

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 code phase error estimating method includes calculating correlation for I and Q components of a reception signal, judging code phase based on the result of the correlation calculation; calculating a ratio of first difference to a second difference, where the first difference is a first correlation value minus a third correlation value and the second difference is a second correlation value minus the third correlation value, the first correlation value being a correlation value at the code phase, the second correlation value being a correlation value at a phase shifted from the code phase by X chip (0<X<1), and the third correlation value being a correlation value at a phase shifted from the code phase by Y chip (1<Y); and estimating the code phase error when the reception signal is a multipath signal.

Abstract: A method for detecting a specific timing from a synchronization channel is described. A signal with a known sequence is received. Two or more correlation values between the received signal and the known sequence are calculated at two or more positions. The two or more correlation values are compared. A determination is made whether the position of the known sequence has been shifted based on the comparison. A specific timing of a synchronization channel is detected based on the determination.

Abstract: A receiving method and apparatus for increasing coherent integration length while receiving a positioning signal from transmitters such as GPS satellites. In order to compensate for frequency drifts that may occur in the positioning signal, a hypothesis is made as to the frequency drift, which is inserted into the receiving algorithm. Advantageously, the length of coherent integration can be increased at the expense of reducing the length of incoherent integration while keeping the total integration length the same, the net effect of which is an increase in signal detection sensitivity. The frequency drift hypothesis has any appropriate waveform; for example, approximately linear or exponential.

Abstract: An early-late gate based ADC timing approach is described for performing early-late gate timing recovery despite the presence of multipath signal distortion. Multipath conditions may severely distort Barker correlator magnitudes generated for taps within two taps of a determined bit synchronization time. Exemplary embodiments of the described approach may combine Barker correlator magnitudes for several receive chains to calculate the timing error correction corresponding to a difference of early and late taps. The approach may be used to increase the size and stability of Barker correlator magnitudes generated for taps far away from a determined bit synchronization time.

Abstract: A communication terminal in which a circuit component can measure active sets thereby to reduce the circuit scale. In the terminal, a synchronization base station switch (105) outputs a switching timing signal so that frequency shift information, reception timing information, and scramble code information on a base station where the received signals of the base stations are despread are outputted at the despreading timing. A scramble code reception timing detecting circuit (106) detects the reception timing of a pilot signal. A scramble code identifying circuit (107) detects a scramble code. A scramble code reception timing memory (110) stores the reception timing information for each base station. A scramble code memory (111) stores the scramble code information for each base station. A demodulating circuit (112) demodulates the received signal according to the reception timing information and the scramble code information.

Abstract: A method and an apparatus for estimating a symbol timing offset in an Orthogonal Frequency Division Multiplexing (OFDM) based communication system are provided. A Carrier to Interference Ratio (CIR) of an Reference Signal (RS) is acquired using received pilot signals. The RS CIR includes power information on channel components of the RS. A CIR of a Secondary Synchronization Channel (S-SCH) is acquired using the received pilot signals. The S-SCH CIR includes power information on channel components of the S-SCH. Unnecessary channel components are suppressed from the RS CIR using the S-SCH CIR. Real channel components of the RS remain. An observation window is set having a predetermined duration for windowing the real channel components of the RS. A first arriving channel component is searched for within the observation window. A start point of data is estimated using the first arriving channel component.

Abstract: A system including a differential demodulation module, a first summing module, and a second summing module. The differential demodulation module generates differentially demodulated signals based on having differentially demodulated received signals. The first summing module generates a combined signal by adding the differentially demodulated signals, wherein the combined signal includes a plurality of symbols. The second summing module generates a plurality of sums for each of a plurality of derived preamble sequences, wherein the derived preamble sequences are derived from preamble sequences, and wherein each of the derived preamble sequences includes a plurality of derived symbols. The second summing module further generates cross-correlation values for the derived preamble sequences based on the plurality of sums, wherein one of the cross-correlation values generated for one of the derived preamble sequences is a sum of the plurality of sums generated for the one of the derived preamble sequences.

Abstract: A method for determining a Doppler shift of a first signal is provided. First, a plurality of Doppler frequency hypotheses is combined to obtain a joint Doppler signal. The first signal is the correlated according to the joint Doppler signal and a plurality of code signals with phases corresponding to a series of code phase hypotheses to obtain a series of correlation results which are then examined to determine whether the Doppler shift does lie in the Doppler hypotheses. A fine Doppler search is then performed to determine the Doppler shift when the Doppler shift lies in the Doppler hypotheses.

Abstract: In a recording and reproducing apparatus for recording and reproducing video data, includes: a shuffling memory (6); a writing means for writing video data into the shuffling memory in accordance with the synchronizing signal and a write reference clock signal in synchronization with the video data; and a reading means for reading out the video data from the shuffling memory in accordance with a synchronizing signal and a stabilized read reference clock which is asynchronous with the write clock signal.