Abstract: A technique for reducing the dwell time in acquiring a satellite signal is provided. The technique minimizes the dwell time in searching for a satellite signal in cells of a search space by comparing the peak-power-to-average ratio (PAPR) to one or more thresholds at one or more intermediate points during the search in a code phase/Doppler frequency bin. The comparison is then used to determine whether to continue the search in a current code phase/Doppler frequency bin or to continue to the next code phase/Doppler frequency bin.

Abstract: An apparatus includes a plurality of antennas, where each antenna is configured to receive wireless signals transmitted using adaptive beam forming. The apparatus also includes a plurality of wireless radios, where each wireless radio is configured to output signals representing the wireless signals received by one of the antennas. The apparatus further includes a plurality of first diversity combiner units, where each first diversity combiner unit is configured to perform spread spectrum diversity combining using the signals output by one of the wireless radios. In addition, the apparatus includes a second diversity combiner unit configured to perform antenna diversity combining using signals output by the first diversity combiner units, where the second diversity combiner unit is configured to output recovered wireless signals.

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: Various embodiments are described herein for a system and method of detecting Automatic Identification System (AIS) signals in space and decoding these signals. In one aspect, a system for performing this function is described which includes a receiver configured to receive the plurality of AIS signals and pre-process the plurality of AIS signals to produce digital input data, and a processing unit configured to process the digital input data to identify one or more candidate AIS message signals based on Doppler offsets associated with the digital input data, determine corresponding Doppler offset estimates and time estimates of the one or more candidate AIS message signals, decode the one or more candidate AIS message signals to obtain corresponding message segments and validate the decoded message segments for proper AIS formatting.

Abstract: A BOC signal acquisition and tracking apparatus and method. In the present invention, at least a BOC signal, a BOC-cos signal and a PRN coded signal are generated for a received signal. Depending on application condition (e.g. acquisition mode or tracking mode), autocorrelation of the BOC signal is combined with cross-correlation of the BOC signal and one of the BOC-cos signal and the PRN coded signal to generate a proper combined correlation result.

Abstract: A method for detecting coherent interference includes the steps of: (a) receiving a signal at a first frequency, (b) forming a set of cross-correlation results by at least cross-correlating the signal with a first known code for a plurality of code offsets, (c) determining a statistical signature of the cross-correlation results, and (d) deciding, based on the statistical signature, whether non-negligible coherent interference is present within a search bin defined by the combination of the first frequency and the first known code.

Abstract: A receiver with multiple antennas, such as an 802.11b receiver may generate a magnitude signal for each antenna and add the results to determine a peak signal point in a received frame to provide a bit synchronization signal to a rake receiver component. The receiver may include one or more threshold switches that only pass individual or combined magnitude signals when the magnitude signals are above a certain level. The received frame may be dividing into segments using a switching circuit and registers. A comparator may then evaluate the registers to determine the segment with the highest magnitude signal. In one embodiment, values for adjacent segments may be added to a current segment when determining the segment with the highest magnitude signal.

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: A method for removing selected signals from a received signal prior to decoding begins by receiving communication signals from a transmitter over a CDMA air interface. The received communication signals are input to a traffic signal cancellation system for canceling unwanted traffic signals, thereby producing an output (O). The received communication signals are input to a pilot signal cancellation system for removing a global pilot signal, thereby producing an output (Oadd). The output (Oadd) of the pilot signal cancellation system is subtracted from the output (O) of the traffic signal cancellation system to provide a cancellation system output.

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: 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.

Abstract: Disclosed are a signal processing method using a code cycle, a correlator, and a software signal receiver. An exemplary embodiment of the present invention provides a signal processing method of a satellite navigation signal, including: a frequency generating step generating a predetermined frequency component for removing a frequency component of sample data; a code generating step generating a predetermined code component for removing a code component of the sample data and increasing a sample count when the predetermined code component is generated; and a correlation value generating step, if the sample count is equal to a count per unit time, generating a correlation value between the generated predetermined frequency component and the generated predetermined code component by reading a sample data block.

Abstract: An apparatus for processing spread spectrum signals is disclosed. The apparatus includes an intermediate frequency (IF) signal preprocessing unit, which includes a first set of multiply-accumulator (MAC) units and a second set of MAC units. The IF signal preprocessing unit generates a first and a second set of data streams using a digitized signal and a first and second local reference signals respectively. Each data stream is generated every predetermined time period, and each data stream includes pre-integration results generated at a predetermined rate.

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 signal receiver including an input that receives a plurality of signals from a respective plurality of channels; a multiplexer unit that receives the plurality of signals from the input and that selects, in a time-division manner, one of the plurality of signals; and at least one phase difference detector that receives the selected signal from the multiplexer unit, a number of the at least one phase difference detectors being less than a number of the plurality of channels.

Abstract: Control circuitry is configured to control a sampler, in a sampling phase determination process, to sample a signal at a sampling period of T±T/n for outputting a sample set for each one of n phases of the sampled signal. Each one of n correlators has a first input configured to receive one of the sample sets, a second input configured to receive a PN signal, and an output which provides a correlation result from a correlation process between the sample set and the PN signal. The control circuitry is further configured to identify, from the correlation results, one of the phases associated with the optimal correlation result. The control circuitry is then configured to control the sampler, in a communication mode, to sample a received signal at a sampling period of T at the phase associated with the optimal correlation result.

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: 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 low complexity RACH preamble detector is described herein. The RACH preamble detection algorithm uses the peak detection of the time domain correlation function through frequency domain processing. The frequency domain processing considers the reference signals generated directly from frequency domain CAZAC sequence or time domain CAZAC sequence with DFT conversion. A low-complexity poly-phase LPF along with down sampling is implemented before the FFT to reduce the required length of the long FFT operation N-folded.

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 synchronization method in a Ultra Wideband (UWB) receiver includes receiving a signal through a multipath channel, and synchronizing with a first multipath component of the received signal by computing a correlation value between the received signal and a template signal of the receiver in a predetermined search range. Since multipath components received at the receiver after the first multipath component of the received signal have lower power than that of the first multipath component, the synchronization with the first multipath component of the received signal may improve the performance in processes after the synchronization process.

Abstract: A multipath searcher and method includes a programmable decimation filter configured to adjust a sample rate of a received pilot signal. A plurality of correlators is configured to compare the received pilot signal to a reference code in a first mode and in a second mode. The first mode includes a low resolution search of a search window performed such that the plurality of correlators encompass an entire search window concurrently and the plurality of correlators receives a delayed reference code delayed to correspond with a portion of the search window in which a corresponding correlator performs correlation to identify peaks in the received pilot signal. The second mode includes a high resolution search of a refined search window only at or near identified peaks discovered in the first mode. The high resolution search is focused at the peak location by adjusting delays in the plurality of correlators.

Abstract: In a mobile communication system using a code division multiple access (CDMA) method, spreading code detection and frame/slot timing synchronization (cell search) is conducted by using a long code masked symbol. The spreading factor of the long code masked symbol is set to a value lower than spreading factors of other ordinary symbols. As a result, it becomes possible to reduce the circuit scale and power dissipation of the mobile terminal and raise the speed of cell search.

Abstract: A MIMO transmitter has a modulator (40,41,42, 120, 122) a demultiplexer 100 arranged to divide the information into one or more demux streams for transmission over different ones of the channels, and a diversity splitter (110) to derive one or more sub-streams of the same information. A decorrelator (120) such as a scrambler (150, 155) decorrelates the sub-streams before or after the modulation. The arrangement is configurable to vary in use a ratio of demultiplexing and of diversity splitting. This balances between the gains from diversity and spatial multiplexing, without needing major changes to the transmit and receive processing.

Abstract: For the first wireless base station, a first correlation value based on a calculation result on channel estimation values having an identical signal timing and a calculation result on channel estimation values having different signal timings, and determines, for the second wireless base station, a second correlation value based on a calculation result on channel estimation values having an identical signal timing, and controls the weighting-adding at the equalizer based on these correlation values.

Abstract: An apparatus and method for multimedia file streaming are provided. In a method for multimedia file streaming in a receiving portable terminal, the method includes determining meta data included in a received packet, generating new meta data having a circular-type media data offset on the basis of the meta data, storing media data included in the packet received in a circular manner according to the media data offset included in the new meta data, and loading the media data stored according to the media data offset included in the new meta data.

Abstract: A signal compression method and apparatus for a base transceiver system (BTS) in a wireless communication network provides efficient transfer of compressed signal samples over serial data links in the system. For the uplink, an RF unit of the BTS compresses baseband signal samples resulting from analog to digital conversion of a received analog signal followed by digital downconversion. The compressed signal samples are transferred over the serial data link to the baseband processor then decompressed prior to normal signal processing. For the downlink, the baseband processor compresses baseband signal samples and transfers the compressed signal samples to the RF unit. The RF unit decompresses the compressed samples prior to digital upconversion and digital to analog conversion to form an analog signal for transmission over an antenna. Compression and decompression can be incorporated into operations of conventional base stations and distributed antenna systems, including OBSAI or CPRI compliant systems.

Abstract: A method and apparatus provide high-sensitivity GPS/GNSS signal acquisition in a stationary GPS/GNSS receiver. The uncertainty in frequency due to apparent Doppler shift is partitioned into a plurality of contiguous frequency bins, and the uncertainty in location of navigation data bit boundaries is partitioned into equally spaced trial bit boundary locations. For each combination of the trial bit boundary location and the frequency bin, a signal block of captured complex baseband signal is Doppler-compensated using a phase rotator, and then synchronously summed with a periodicity of one period of C/A code so as to produce a compressed sample block having N samples. Each compressed sample block is cross-correlated with one period of reference C/A code to produce an N-value correlation function. A predetermined number of magnitudes of the N-value correlation functions are stack-accumulated into an array with precession compensation so as to find a correlation peak having the largest value.

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: A signal compression method and apparatus for a base transceiver system (BTS) in a wireless communication network provides efficient transfer of compressed signal samples over serial data links in the system. For the uplink, an RF unit of the BTS compresses baseband signal samples resulting from analog to digital conversion of a received analog signal followed by digital downconversion. The compressed signal samples are transferred over the serial data link to the baseband processor then decompressed prior to normal signal processing. For the downlink, the baseband processor compresses baseband signal samples and transfers the compressed signal samples to the RF unit. The RF unit decompresses the compressed samples prior to digital upconversion and digital to analog conversion to form an analog signal for transmission over an antenna. Compression and decompression can be incorporated into operations of conventional base stations and distributed antenna systems, including OBSAI or CPRI compliant systems.

Abstract: This disclosure relates to method, device and system for determining transmit power in a communication system. A node receives an access point interference signal from an access point. The access point interference signal is measured by the access point based in part on an inference from an external system. The node determines a transmit power based in part on the access point interference signal. The node then transmits an uplink signal at the transmit power.

Abstract: A correlation apparatus for tracking a satellite signal includes a shifter, a multiplexer and an accumulator. The shifter generates generating a Prompt signal, a plurality of Early signals and a plurality of Late signals. The multiplexer outputs at least one of the plurality of Early signals and at least one of the plurality of Late signals. The accumulator acquires a correlation signal to tracking the satellite signal.

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 satellite-based positioning system reception device comprises a function for detecting false lock-ons based on a linear combination of complex signals arising from correlation pathways between a signal received from a satellite and a prompt local code and a plurality of local codes shifted by determined delays with respect to the prompt local code. An advantage is that the function for detecting false lock-ons makes it possible to remedy the false lock-ons due to multi-path phenomena.

Abstract: Embodiments of the present invention provide a method to produce a modulation signal comprising combining at least two modulation signals, for example, BOCs or derivatives thereof, having portions (chip or a number of chips) thereof with respective relative phases or states ({++,??} and {+?,?+}) selected such that the average of a plurality of said portions at least reduces cross spectral terms of the composite complex spectrum of said at least two modulation signals.

Abstract: An aspect of the invention is a signal processing method for correlating an N-bit received signal with an N-bit code word signal, wherein the method comprises steps of preprocessing said N-bit received signal and said N-bit code word signal, performing a Fourier transform (126) for said preprocessed signals, multiplying (130) said Fourier transformed preprocessed received signal with said Fourier transformed preprocessed code word signal, and performing inverse Fourier transform (140) to a product of said multiplication. The method is characterized in that said preprocessing comprises a step of resampling (123, 125; 135) at least one of said signals with N bits to a length of at least N+1 bits with interpolation means.

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

Abstract: A multipath signal determination method includes carrying out correlation operation between a received signal of a positioning signal spread-modulated with a spread code and a replica signal of the spread code with respect to each of IQ components at a predetermined sampling phase interval, and determining whether the received signal is a multipath signal or not, in accordance with a plot position in the case where each correlation value in each of the sampling phases is sequentially plotted on an IQ coordinate.

Abstract: A wireless device comprising a plurality of chips may be operable to dynamically configure wireless communication between the plurality of chips. Each of the chips may include one or more transceivers and one or more integrated directional antennas communicatively coupled to the one or more transceivers. The communications link between chips in the wireless device may be dynamically configured via control of the transceivers and/or the integrated directional antennas. The antennas may include patch antennas and/or dipole antennas. The transceivers may be configured by controlling output power of power amplifiers or by controlling gain of low noise amplifiers. The communications link may be dynamically configured by controlling a characteristic impedance of the antennas for impedance matching to transceivers. A frequency of the communication link may be controlled by configuring the antennas. A bandwidth of the communications link may be configured based on activity of processors in the wireless device.

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: The present invention relates to a method for transmitting data Di in a telecommunication system SYST including a first transceiver TXi and a second transceiver RX linked together by means of a communication channel Chi, one of which transceivers being mobile, which method includes: a spreading step for spreading said data Di over a plurality of components Ctj (for j=1 to M), and an equalization step during which each component Ctj (for j=1 to M) is multiplied by an equalization value Wi(j)* representative of communication conditions within the communication channel Chi. According to the invention, the equalization values Wi(j)* are also representative of a Doppler effect generated by movement of the mobile transceiver. The invention enables to significantly compensate for alterations caused to the communication channel Chi by movement of the mobile transceiver.

Abstract: Improved decision directed adaptation and decision feedback equalizers are provided in a block coded digital communication system. The performance of a receiver is significantly improved by allowing the decision feedback equalizer to perform time-tracking and residual frequency offset compensation during the data portion of a frame. This is accomplished by capitalizing on the inherent correlation among the chips of a code word in a block coded digital communication system to identify certain instances where more reliable symbol estimates can be derived from a sliced chip without introduction the delay inherent in decoding. As the more reliable symbol estimates are fed back into the chip slicer, the total efficiency of the decision feedback equalizer is improved and the more reliable symbol estimates can be used to replace older content in the feedback filter to further improve the accuracy of the modified slicer input and further decrease the effects of error propagation by the decision feedback equalizer.

Abstract: According to an embodiment of the present invention, a shared processor architecture in a receiver system is disclosed. The receiver system is configured to have a first functional stage and a second functional stage for processing information carried by signals from a first transmitter system and a second transmitter system respectively. The first functional stage and the second functional stage correspond to an identical signal processing function. The shared processor architecture includes a first processor, allocated to the first functional stage and the second functional stage, for processing an output generated from the first functional stage or an output from the second functional stage.

Abstract: A global positioning system (GPS) receiver that is configured to rapidly acquire GPS signals in space applications and a method for rapidly acquiring GPS signals in space applications is disclosed. In an embodiment, the GPS receiver includes, but is not limited to, a GPS signal acquisition component comprising a time domain correlation module. The GPS signal acquisition component is adapted to acquire a GPS signal by receiving data from the GPS signal and processing the data to detect the GPS signal.

Abstract: A method and apparatus is disclosed herein for forward-backward SOMA techniques. In one embodiment, the apparatus is a receiver comprising: an inner decoder structure having a soft output M-algorithm (SOMA) based multiple-in multiple-out (MIMO) joint demapper that uses a SOMA-based MIMO detection process to perform joint inner demapping over each tone, where the SOMA-based MIMO joint demapper is operable to identify a best candidate among a number of candidates by searching a detection tree for each tone using a forward pass through the detection tree, where only a number of best alternatives from every level of the tree are expanded and where soft-output related information is collected and stored, and to perform a second pass, following the forward pass, during which soft-output is computed for each bit; and an outer decoder operable with the SOMA-based inner decoder to perform iterative decoding.

Abstract: A method for estimating the speed of a mobile device in a network is provided that includes selecting a correlation length from a plurality of possible correlation lengths. A correlation result is generated based on the selected correlation length. A speed estimate is generated for the mobile device based on the correlation result.

Abstract: A multipath detector includes an RF module receiving multiple signals, and a correlator module receiving the signals from the RF module. The correlator module correlates the signals to create a composite ACF, and produces samples of the composite autocorrelation function (ACF). The samples are time delayed relative to each other. The multipath detector also includes a carrier phase processor that receives the samples and estimates carrier phases associated with each of the samples. The carrier phase processor employs the estimated carrier phases to determine if one of the signals is subject to a multipath delay.

Abstract: Signal impairment correlations for multiple signals in a received multipath signal are constructed by fitting parametric models associated with each high-data-rate signal in the multipath against measured impairment correlations. The estimated model fitting parameters are applied to form impairment correlation estimates for all signals. The models comprise a separate impairment covariance matrix scaled by a model fitting parameter for each high-data-rate signal and a noise covariance matrix scaled by a noise element model fitting parameter. The model fitting parameters may be estimated by a least-squares formulation and applied to form impairment correlation estimates for all signals of interest. The resulting impairment correlation estimates may be provided to G-RAKE receivers or joint scaling demodulators to demodulate the signals while suppressing interference from the high-data-rate signals.