Abstract: A communication method comprises generating a Golay code having a zero-DC level when differentially encoded and continuously rotated. A preamble of a data stream is spread with the Golay code, and the data stream is modulated with continuous phase modulation (CPM), such as constant envelope 2-CPM, before being transmitted. A method for acquiring a received signal having a spread sync field modulated with 2-CPM comprises performing chip-level differential detection of the received signal, correlating the received signal with a Golay sequence; and accumulating the correlator outputs.

Abstract: Embodiments of the present invention disclose a code channel detecting method and a related device and a communication system. In the solutions provided by the embodiments of the present invention, whether a DPA code channel is in an active state is determined with multiple thresholds based on a first reference value and a third reference value, or based on a first reference value, a second reference value and a third reference value. This mechanism takes multiple possible false determination situations into consideration, thereby ensuring a code channel correct detection rate in multiple interference scenarios and relatively reducing a false alarm rate.

Abstract: A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to the synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.

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

Abstract: Embodiments of a spread-carrier self-detecting code (SCSDC) receiver with summed-delay processing (SDP) and method are generally described herein. In some embodiments, the SCSDC-SDP receiver is arranged to generate a chip-matched filter output from a received spread-spectrum signal and perform SDP on the chip-matched filter output with a plurality of delay-processing chains. The SDP may include multiplying a conjugated and delayed chip-matched filter output with the chip-matched filter output and applying a code-matched filter that is matched to a delay-multiplied code. The outputs from the code-matched filters of each delay-processing chain may be coherently combined to provide an output having correlation peaks for use generating frequency error and timing information.

Abstract: The present invention discloses a method for implementing automatic frequency control, and an apparatus thereof. The method discloses: calculating a correlation value of common pilot symbols in a reception signal of each path and a frequency offset value, calculating a combined frequency offset value according to the frequency offset value of each path, and determining, according to the combined frequency offset value, a frequency offset adjustment value for a voltage controlled oscillator, a frequency offset adjustment value for overall reception signals and a frequency offset adjustment value for the reception signal of each path. The present invention selects a method of small-scope frequency offset estimation, which makes frequency offset estimation more accurate.

Abstract: A method and system is disclosed for designing a radio for down-converting RF signals to IF signals by sampling the signals in a round-robin sampling circuit and multiplying the samples by coefficients that are changed at a fixed rate equal to the rate of operation of each of the sampling circuits. The circuit is able to down-convert multiple channels simultaneously to adjacent positions in the IF band, while rejecting unwanted image signals. The method and system avoids the difficulty and cost of directly digitizing the RF signal, allowing each component to operate at a greatly reduced speed. The coefficients are selected to provide the desired transfer function while keeping the output signal centered at a desired frequency.

Abstract: A surface acoustic wave (SAW) correlator spread-spectrum (SS) receiver is disclosed which utilizes a first demodulation stage with a chip length n and a second demodulation stage with a chip length m to decode a transmitted SS signal having a code length l=n×m which can be very long (e.g. up to 2000 chips or more). The first demodulation stage utilizes a pair of SAW correlators which demodulate the SS signal to generate an appropriate code sequence at an intermediate frequency which can then be fed into the second demodulation stage which can be formed from another SAW correlator, or by a digital correlator. A compound SAW correlator comprising two input transducers and a single output transducer is also disclosed which can be used to form the SAW correlator SS receiver, or for use in processing long code length signals.

Abstract: A multimode communication device with a shared signal path programmable filter and a method for utilizing a shared signal path programmable filter in a multimode communication device. Various aspects of the present invention comprise a first module adapted to receive a first communication signal (e.g., corresponding to a first communication protocol) and a second module adapted to receive a second communication signal (e.g., corresponding to a second communication protocol). A shared filter, communicatively coupled to the first and second modules, may be adapted to filter the first and/or second communication signals in accordance with a plurality of selectable sets of filter response characteristics (e.g., associated with the first and second communication protocols). A filter control module may be adapted to select a set of filter response characteristics from a plurality of such sets and program the shared filter to filter a communication signal in accordance with the selected set.

Abstract: A method for noise rise estimation in a wireless communication system comprises receiving (210) of radio signals. An interference whitening (212) is performed. A useful signal power for a first user after the interference whitening is determined (214) for a plurality of time instances. Furthermore, a first user noise floor compensation factor is derived (216) based on combining weights for the first user used in the interference whitening. A probability distribution for a compensated useful signal power for the first user is estimated (218). A conditional probability distribution of a noise floor measure is computed (220). A noise rise measure for the first user is then calculated (222) based at least on the compensated useful signal power for the first user and the conditional probability distribution of a noise floor measure.

Abstract: One embodiment of the present invention relates to an analog correlation unit comprising a plurality of parallel correlation components configured to operating according to an advanced switched-capacitor low pass filter principle that increases coding gain of the unit. Each correlation component comprises a sampling stage and a correlation stage. The sampling stage may comprise a switched capacitor configured to sample a received baseband signal to determine a value (e.g., polarity) of the baseband signal. The sampled baseband signal is provided to the correlation stages, which may respectively comprise a plurality of switched integrators configured to selectively receive and integrate the sampled baseband signal over time depending upon values (e.g., polarity) of the correlation code to generate voltage potential values. The analog correlation result is evaluated by a comparison of an adjustable threshold voltage with the difference between the output voltage potential values.

Abstract: A correlation calculating method of correlating a received code signal obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, with a replica code signal is provided which includes: correlating values of the replica code signal in a chip period with values of the received code signal at first to n-th arrival times obtained by varying an arrival time of the chip period by 1/n chip (where n is an integer equal to or greater than 2); and acquiring a correlation calculation result at a 1/n chip interval by synthesizing the correlation calculation results.

Abstract: A signal processor for GPS or other GNSS radiolocalization systems, includes a RAM pre-correlation buffer which is filled in sync with the code NCO, thus all sample alignment in the buffer is fixed The device further includes an amplitude compressor to limit the size of the buffer memory and is optimized to provide data to the following DFT unit in small bursts that can be processed in real time without the need for intermediate buffers. Thanks to these features the processor limits the amount of fast intermediate memories, is simpler and has lowerpower consumption.

Abstract: A signal acquisition system efficiently acquires a transmitted signal even at very low power. The system may synchronize to a preamble structure in the transmitted signal and, for example, determine timing parameters that locate the preamble with respect to system timing or other clock references. The system is particularly effective at acquiring weak power signals and is also robust against significant noise and other impairments, and therefore improves the ability of a receiving device that incorporates the signal acquisition system to acquire the signal and establish communication with other devices.

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: A path searcher for use in a spread spectrum receiver, including a correlator for correlating a received signal in different time positions with a reference code to select for further processing time positions of the signals showing the strongest correlations, wherein the correlator is operable to obtain a correlation energy result for each time position in a set of possible time positions, a comparator for comparing the correlation energy results with each of a plurality of energy thresholds and a recorder for recording data indicating time positions for correlation energy results which are not less than the respective thresholds in different groups corresponding to the respective thresholds. Also described is a semiconductor device and a receiver incorporating the path searcher and a method of operation of the path searcher.

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: 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: 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: 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: A method for performing delay locked looping upon a received signal which reduces the asymmetry of auto-correlation function resulting from sampling is provided. The received signal is a spread spectrum code signal, and the method includes: generating a plurality of replica spread spectrum code signals according to an estimated code phase delay and phase spacing, the replica spread spectrum code signals having phases respectively different from the phase of the received signal; calculating a spread spectrum code error statistics signal according to the replica spread spectrum code signals and the received signal; and adjusting the estimated code phase delay according to the spread spectrum code error statistics signal and a phase difference between a sampled point of at least one replica spread spectrum code signal and a corresponding signal transition point.

Abstract: A wireless device (24) receives a reference signal over a radio channel (21). The reference signal may be Positioning Reference Signals (PRS) and/or Common Referencing Signals (CRS), and may be transmitted from a transmitter (22). The wireless device (24) comprises a correlator (100); a reference signal detector (102); a threshold selector (106); and a reference signal analyzer (108). The correlator (100) use a signal received from the radio channel (21) and a replica of the reference signal to provide a correlator output value. The reference signal detector (102) compares the correlator output value with a threshold value to detect presence of a reference signal, and to estimate an arrival time of the reference signal. The threshold selector (106) adapts the threshold value to at least an estimate of a relative amount of noise and interference power in the received signal.

Abstract: Techniques for facilitating cell search by user equipments (UEs) in a wireless communication system are described. In an aspect, a primary synchronization code (PSC) sequence may be generated based on a Frank sequence and a constant amplitude sequence that is repeated multiple times. In another aspect, a set of PSC sequences may be generated based on complementary sequences having good aperiodic correlation properties and efficient implementations. In one design, PSC sequences A+B and B+A may be formed based on Golay complementary sequences A and B, there “+” denotes concatenation. In yet another aspect, a set of secondary synchronization code (SSC) sequences may be generated based on a set of base sequences and different modulation symbols of a modulation scheme. Each base sequence may be modulated by each of M possible modulation symbols for the modulation scheme to obtain M different SSC 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: The teachings presented herein improve the processing of individual signals of interest included in a received composite signal by computing combining weights and/or signal quality estimates for each signal of interest, e.g., for linear equalization, based on either shared or non-shared correlation estimates. As a non-limiting advantage, the use of shared correlation estimates reduces computational loading as compared to the processing load that would be needed for computing non-shared correlation estimates for all signals of interest. As a further non-limiting advantage, the conditional use of shared and non-shared correlation estimates provides for the use of non-shared correlation estimates where signal characteristic(s) of one or more of the signals of interest warrant such usage, e.g., for one or more high-rate signals of interest.

Abstract: Techniques, apparatuses and systems for providing communications based on time reversal of a channel impulse response of a pulse in a transmission channel between a transmitter and a receiver to enhance reception and detection of a pulse at the receiver against various effects that can adversely affect and complicate the reception and detection of the pulse at the receiver.

Abstract: Direct detection of wireless interferers in a communication device for multiple modulation types. One or more radios implemented within a communication device is/are operative to receive and process wireless communications. A wireless communication signal is processed to extract symbols there from. Various symbols groups are processed in accordance with correlation processing to identify potential interferers (e.g., other communication devices using common portions of frequency spectra). Alternatively, matched filter processing (e.g., using a Barker matched filter in some embodiments) operates on the various symbol groups to identify some potential interferers. Various combinations of correlation processing and matched filter processing may be employed in other instances (e.g., using any of a desired means of comparison, combining, etc.) in considering interferers identified in accordance with each of these two means.

Abstract: A baseband processing module includes an RX interface, a rake receiver combiner module, and may include additional components. The RX interface receives the baseband signals from an RF front end and creates baseband RX signal samples there from. The rake receiver combiner module includes control logic, an input buffer, a rake despreader module, and an output buffer. The rake despreader module is operable to despread the baseband RX signal samples in a time divided fashion to produce channel symbols including pilot channel symbols and physical channel symbols.

Abstract: A method of wireless communication in a lossy environment entails generating a direct sequence spread spectrum (DSSS) code string that includes a pseudo-noise (PN) sequence followed by instances of shifted PN sequences, where the shifted PN sequences are produced in response to the content of the message. The PN sequence includes a plurality of chips arranged in a first order, and each of the shifted PN sequences includes the plurality of chips arranged in another order. A beacon signal modulated by the DSSS code string is transmitted from a transceiver and received at a receiver within the communication system. Correlation peaks are formed at the receiver, where each correlation peak is associated with one of the PN sequences or one of the shifted PN sequences. Shift values are determined from the correlation peaks and the shift values are decoded to produce the message at the receiver.

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

Abstract: A transmission device of the present, invention includes a baseband waveform generator to generate a transmission signal by using a transfer function H0(f) that is in a relation of a matched filter with a transfer function H1(f) in an analog domain of a transmission side and a reception side connected through a wireless channel, and transmits the transmission signal generated by the baseband waveform generator.

Abstract: Embodiments of the present invention provide a system and method for further reducing cyclostationarity and correspondingly energy density in a chaotic spread spectrum data communication channel, by digitally generating a first chaotic sequence of values to form a spreading code. The spreading code is then used to form a digital IF spread spectrum signal having a uniform sampling interval. The digital IF spread spectrum signal is converted to a sampled analog IF spread spectrum signal at a conversion rate substantially equal to the uniform sampling interval. The duration of the sampling interval is then selectively varied in accordance with a first pseudo-random sequence, thereby introducing a known dither in the analog IF spread spectrum signal. After introducing the known dither, the analog IF spread spectrum signal is upconverted to an analog RF spread spectrum signal. The first pseudo-random sequences may be designed to be a chaotic sequence.

Abstract: Embodiments of a spread-earner self-detecting code (SCSDC) receiver with summed-delay processing (SDP) and method are generally described herein. In some embodiments, the SCSDC-SDP receiver is arranged to generate a chip-matched filter output from a received spread-spectrum signal and perform SDP on the chip-matched filter output with a plurality of delay-processing chains. The SDP may include multiplying a conjugated and delayed chip-matched filter output with the chip-matched filter output and applying a code-matched filter that is matched to a delay-multiplied code. The outputs from the code-matched filters of each delay-processing chain may be coherently combined to provide an output having correlation peaks for use generating frequency error and timing information.

Abstract: Apparatus for determining a location of a peak in correlation output samples, the apparatus being arranged to receive samples from at least one correlator over a plurality of symbol time periods; combine samples from a period that is longer than the symbol time period into combined samples; and determine the position of a peak in the combined samples.

Abstract: Certain aspects of a method and system for delay matching in a rake receiver for WCDMA closed loop modes are disclosed. Aspects of one method may include selecting a set of channel estimates from a plurality of channel estimates generated for a delay matched branch and/or a non-delay matched branch in a rake receiver. A plurality of weight factors may be generated based on the selected set of channel estimates. In the delay matched branch of the rake receiver, the application of the generated plurality of weight factors may be delayed by a particular time period. A delay associated with a control channel and/or a data channel may be compensated based on the delayed application of the generated plurality of weight factors.

Abstract: An aspect of the invention is a signal processing method for correlation computation between received signal samples, code replica and carrier replica. The method is characterized in that the method comprises steps of: mapping (110) received signal samples into a range of unsigned integers; separating (120) bits of the mapped N-bit sample sequences into N sequences of bits; performing at least one exclusive or (XOR) operation between a sequence of bits and the code; counting (140) number of bits having value 1 in the result of the exclusive or (XOR); remapping (150) the sum back into numeric range of the received signal samples; multiplying the remapped sum by carrier replica; and accumulating (170) the product of multiplication for an interval of at least a code epoch.

Abstract: Traffic management reports are created by providing vehicle sensor devices at different location in a region. Each device captures data of vehicles that pass the device. The vehicle data is communicated to a central computer database. At the central computer database, a user interface selects one or more criteria from a plurality of criteria for filtering the vehicle data. Traffic management reports are then automatically created from the filtered vehicle data using the selected criteria.

Abstract: Certain aspects of a method and system for achieving space and time diversity gain are disclosed. Aspects of one method may include modifying a generalization code of at least one pilot channel, to measure signal strengths for each of a plurality of received multipath signals. A portion of the plurality of received multipath signals may be combined based on the measured signal strengths. The signal strengths of the plurality of received multipath signals may be measured on a primary pilot channel by assigning its generalization code to zero. The signal strengths of the plurality of received multipath signals on a secondary pilot channel may measured by assigning its generalization code to a non-zero value.

Abstract: A channel estimation method and apparatus using a self-tracking algorithm is provided for improving channel estimation accuracy. The channel estimation apparatus of a mobile terminal includes a receiver for converting a received radio signal into a baseband signal, a match filter for converting the baseband signal into a digital signal including at least two samples, a channel estimator for buffering the samples, for analyzing multipath signals to predict a maximum power position and multipath energy, and for estimating a channel by selecting a multi-tap at the maximum power position through a slew control, an equalization controller for calculating an equalization tap gain using the multi-tap selected by the channel estimator, and an equalizer for compensating for distortion in the samples output by the channel estimator using the equalization tap gain calculated by the equalization controller.

Abstract: Signal sequence detection techniques are provided to enable a wireless communication device to detect presence of a sequence, such as a preamble sequence, in the presence of other transmission that would otherwise interference with the ability of the device to detect the sequence. At the wireless communication device, energy in a frequency band is received and a receive signal is generated from the received energy. The receive signal is divided into windows of a predetermined time duration. A running auto-correlation of the receive signal is computed to produce an auto-correlation sequence for a sequence to be detected in the receive signal. Data representing a mask is generated for a window based on the receive signal. The mask is applied to the auto-correlation sequence to filter out portions of the auto-correlation sequence that are outside of the mask. A position of sequence, e.g.

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: A computer research tool for inputting, searching, displaying, and analyzing metabolic-related clinical data utilizing a novel graphical user interface (GUI) for visual-statistical data analysis and insight generation and method thereof are disclosed.

Abstract: To generate a pulse for ranging, a kernel is convolved with a spreading sequence. The spreading sequence is parametrized by one or more ordered (length, sparsity) pairs, such that the first sparsity differs from the bit length of the kernel and/or a subsequent sparsity differs from the product of the immediately preceding length and the immediately preceding sparsity. Alternatively, a kernel is convolved with an ordered plurality of spreading sequences, all but the first of which may be non-binary. The pulse is launched towards a target. The reflection from the target is transformed to a received reflection, compressed by deconvolution of the spreading sequence, and post-processed to provide a range to the target and/or a direction of arrival from the target.

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: In a wireless communication system, a method and apparatus switches operating modes of a receiver receiving data and operating in a first mode. The method comprises determining whether a criteria is met to switch the operating mode of the receiver. The operating mode of the receiver is switched from the first mode to a second mode if the criteria is met.

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 technique for receiving spread spectrum GMSK signals that demodulates Gaussian Minimum Shift Keying transmissions involving a sequence of data symbols, a spread spectrum code comprising a sequence of spread spectrum chips, a sequence of pre-modulation chips combining the sequence of data symbols with the spread spectrum chips, wherein for each data symbol, at least one of the pre-modulation chips is generated by taking into account at least the data symbol and at least one of the spread spectrum chips.

Abstract: A method is described to compensate for deviation error in a H-CPM sync or data burst received by a MLSE receiver in a communication device. The deviation error is estimated and matched filter coefficients are adjusted using the estimated deviation error. Metrics are determined for the current state using the adjusted matched filter coefficients. The state having the minimum metric is determined to be the most likely current state. The most likely previous state is similarly determined. The burst is reconstructed backward from the last state to the initial state. The metric is the squared magnitude of the difference between the channel estimate multiplied by the matched filter coefficient associated with one of the possible states and the current state. Timing and frequency errors are compensated for before estimation and correction of the deviation error. Pilot or sync symbols are used in estimating the deviation error.

Abstract: Examples are disclosed for determining a bit error rate (BER) associated with decoding data transmitted using space-time spreading (STS) in a wireless communication system.