Abstract: A receiver receives signals and noise over a frequency spectrum of a desired received signal. The desired received signal is spread using code division multiple access. The received signals and noise are demodulated to produce a demodulated signal. The demodulated signal is despread using a code uncorrelated with a code associated with the desired received signal. A power level of the despread demodulated signal is measured as an estimate of the noise level of the frequency spectrum.

Abstract: Methods and apparatus for transmitting data at a varying effective data rate (EDR) at a constant baud rate by encoding the data prior to transmission with a sequence. In embodiments, the sequence comprises a pseudo random number sequence, Barker sequence, and/or other sequence. Embodiments of a receiver decode the data transmitted at a varying effective data rate (EDR) at a constant baud rate by encoding the data prior to transmission with a sequence.

Abstract: In some embodiments, apparatus and systems, as well as methods, may operate to shift signal data associated with a set of receivers, in time or phase with respect to signal data associated with a receiver reference point, to transform the signal data into shifted data, wherein the signal data corresponds to energy waves propagated through a geological formation before being received by the set of receivers; to multiply the shifted data by a complex conjugate of the signal data associated with the receiver reference point to provide differential phase values; to sum and average the differential phase values to provide differential phase semblance values; and to publish the differential phase semblance values, or information derived from the differential phase semblance values to one of a storage medium, a hardcopy printout, or a display. Additional apparatus, systems, and methods are disclosed.

Abstract: In a radio communication system a first radio station performs communication by the use of a first radio signal. A second radio station receives a second radio signal which is indistinguishable from the first radio signal. A third radio station is in a radio communication area of the first radio station and a radio communication area of the second radio station. A communication format conversion unit generates a third radio signal by converting a communication format of the second radio signal to a communication format which is distinguishable from the first radio signal, and communicates with the third radio station by the use of the third radio signal.

Abstract: A method for providing precoding weights for data symbols of data control subframes includes generating a downlink frame having control subframes which individually correspond to one of a plurality of downlink data subframes, and inserting weight information into each of the control subframes, such that the weight information is to be applied to data symbols present in the corresponding one of the data subframes. The method further includes transmitting the control subframes and the inserted weight information to a receiving device.

Abstract: In a radio communication system a first radio station performs communication by the use of a first radio signal. A second radio station receives a second radio signal which is indistinguishable from the first radio signal. A third radio station is in a radio communication area of the first radio station and a radio communication area of the second radio station. A communication format conversion unit generates a third radio signal by converting a communication format of the second radio signal to a communication format which is distinguishable from the first radio signal, and communicates with the third radio station by the use of the third radio signal.

Abstract: A system and method are provided for extracting and demodulating one or more channels in a radio signal. The method includes receiving a first radio signal using a radio frequency front end, translating a first band of frequencies of the first radio signal to a second band of frequencies to generate a second radio signal, digitizing the second radio signal to generate a digital signal, extracting one or more additional band of frequencies of the digital signal, each additional band of frequencies corresponding to a channel, and demodulating one or more channels to generate a respective demodulated signal. In another aspect, a system and method are provided for modulating and combining one or more channels into a radio signal.

Abstract: A method and system for the estimation and correction of the multipath delay is described. The method comprising analyzing the distortion of the autocorrelation function of each single impulse received with that of an ideal impulse, deriving back the variation of the impulse parameters and estimating the effect of the multipart to be taken into account for compensation on the estimation of the time of arrival (TOA) of the electromagnetic signal.

Abstract: System(s) and method(s) that facilitate assignment mismatch recovery are provided. A projected level of resources required to satisfy one or more communication constraints (e.g., inter-cell and intra-cell interference) is generated. The projected resources are contrasted with scheduled resources and a determination is made as to whether a mismatch between assigned and projected resources exists. A mismatch is recovered through an adaptive response that feeds back magnitudes for the communication resources which are compatible with the communication constraints.

Abstract: A reliability metric is used for determining whether to prune a decoding hypothesis. For example, a reliability metric can be generated for each possible hypothesis generated during blind decoding operations. The reliability metric can then be used in a pruning process whereby a determination to prune a given hypothesis is based on whether the corresponding reliability metric is above or below a reliability metric threshold. In some aspects, the reliability metric is based on the correlation between the symbols of a hypothesis and re-encoded symbols that are based on the hypothesis, whereby the correlation is normalized using an estimated power parameter that is independent of the hypothesis. Through the use of the reliability metric, decoding may be achieved with a low probability of false passes (in the case of noise) and a low probability of missed detection (in the case of a real signal).

Abstract: A system and method to manage files on an online cloud storage system are disclosed. In some embodiments, files stored on the online cloud storage system may be associated with a geographical location and a geographical range. A location of a user may be received. The system and method may determine a level of access to the file for the user based on the location of the user and the geographical location and geographical range of the file. If the location of the user is within the geographical range of the geographical location of the file, then the user may be given a level of permission to access the file stored on the online cloud storage system.

Abstract: A direct-sequence spread spectrum signal receiving device may comprise a receiver unit, a chip sequence generating unit, a correlation unit, and comparison unit. The receiver unit may extract a chip stream from a radio-frequency signal, said chip stream containing a first chip sequence. The chip sequence generating unit may generate a plurality of trial chip sequences on the basis of a first trial chip sequence and on the basis of a plurality of index rotations. The correlation unit may determine a plurality of correlation values on the basis of said plurality of trial chip sequences and on the basis of said first chip sequence, each of said correlation values indicating a degree of correlation between a respective one of said trial chip sequences and said first chip sequence. The comparison unit may determine whether a maximum one of said correlation values exceeds a defined threshold value.

Abstract: A satellite signal navigation receiver can reduce channel resource usage and matched filter requirements by producing a single-bit local replica code from the combined incoming signals of each in view satellite. In one embodiment, the E1-B and E1-C signals from a Galileo satellite are received and converted into single-bit digital representations (B and C, respectively). A modified local replica code D is created by modifying (B?C) by replacing all “?2” values with “?1” values, by replacing all “+2” values with “+1” values, and by replacing all zero values such that a sum of the replaced zero values over a predetermined period will approximately equal zero. For instance, the “0” values can be replaced with alternating “?1” and “+1” values. Another modified replica code D* can be created by modifying (B+C) in a similar manner.

Abstract: The subject matter disclosed herein relates to detecting and/or estimating multipath signals. For an example, a signal comprising at least one binary offset carrier (BOC) modulation signal is received. The BOC modulation signal is modulated with a pseudorandom noise sequence comprising a plurality of chips, wherein each of said chips has a set interval. In another aspect, the received signal is correlated with portions of the plurality of chips to provide a power signal. The portions of chips are less than the set interval. In a further aspect, presence of a multi-path signal in the received signal is detected. The detection of multipath is based, at least in part, on one or more characteristics of the power signal.

Abstract: A diversity combining method applied by a receiver in a wireless communication system is provided, including: acquiring baseband signals of receiving channels corresponding to multiple receiving antennas, and combining multiple acquired baseband signals according to a Maximal-Ratio Combining (MRC) principle at an intermediate frequency and/or within an equalizer and/or after the equalizer. Further a receiver in a wireless communication system is provided. By means of the technical solutions of the disclosure, it is possible to improve a demodulation threshold and the demodulation sensitivity of a microwave system.

Abstract: An electronic receiver may generate a differential detection sequence based on a received symbol sequence and based on a m-symbol delayed version of the received symbol sequence, where m is an integer greater than 1. The particular differential detection sequence may be a result of an element-by-element multiplication of the particular received symbol sequence and the conjugate of an m-symbol delayed version of the particular received symbol sequence. The receiver may calculate differential decision metrics based on the differential detection sequence and based on a set of differential symbol sequences generated from the set of possible transmitted symbol sequences. The receiver may generate a decision as to which of a set of possible transmitted symbol sequences resulted in the received symbol sequence, where the decision is based on the differential decision metrics and the set of possible transmitted symbols sequences.

Abstract: A method and apparatus are provided to generate a preamble signal. A peak of each pulse of the preamble signal is synchronized with a sensitivity region of a super regenerative receiver (SRR). The method and apparatus are configured to transmit, to the SRR, a data packet comprising the preamble signal, wherein the data packet is a baseband signal corresponding to the preamble signal.

Abstract: A method and apparatus for performing time synchronization and an OFDMA receiver thereof are provided. The method preferably includes performing a differential phase correlation in a frequency domain based on one received sequence and one reference preamble and detecting an integer frequency offset based on a result of the differential phase correlation. The method and apparatus advantageously enable the use of one OFDM symbol to estimate ICFO and the use of a simple method to facilitate ICFO detection. Moreover, the performance of the integer frequency offset estimation becomes more robust in high noise and time-variant fading channels, with reduced hardware complexity.

Abstract: A method of detecting a transmission. The method includes: measuring, from a first portion of a received spread-spectrum signal, a first code-phase of a spreading-code; measuring, from a second portion of the signal, a second code-phase of the spreading-code; comparing the first and second code-phases; and detecting whether the transmission is present according to the result of the comparison. Also disclosed are corresponding methods and apparatus for transmission and reception of signals.

Abstract: The present invention relates to a method of reducing equalizer complexity in communication systems, which also provides for reduced power dissipation. The method consists of reducing the number of channel responses expected by the equalizer by averaging sub-groups of all of the possible the channel responses chosen in a particular way.

Abstract: A computer-based distributed error correction scheme with an efficient decoding algorithm is disclosed. The efficiency of the corresponding decoding algorithm, based on standard single source Reed-Solomon error correcting codes, makes the practical employment of the DECC feasible. Various implementation examples are also provided.

Abstract: An interference cancelling receiver combines data from multiple paths after aligning to transmitter timing, and uses either an equalizer or a Rake receiver to compute symbol estimates. Interference estimates are generated from the symbol estimates, and multiple interference estimates are combined after re-aligning the interference estimates to receiver timing. At least two segments of symbol estimates are computed for each segment of interference cancelled data. Various techniques may be employed for controlling the latency and sequencing of these operations, and the subsystems within the canceller may use different processing clock speeds.

Abstract: A method includes, in a receiver, receiving a Multiple-Input Multiple-Output (MIMO) signal over a first plurality of partially-dependent communication channels that have a finite mutual dependence. Second channel responses are estimated in the receiver, for a second plurality of independent communication channels, which are derived from the partially-dependent communication channels and which have no mutual dependence. First channel responses are calculated for the first plurality of the partially-dependent communication channels, based on the second channel responses of the independent communication channels.

Abstract: A transmit power control scheme for use in point-to-multipoint communication uses a random access channel for power control signals transmitted by the receiving stations (200).

Abstract: A method of communicating a data chirp signal from a transmitter to a receiver, the data chirp signal including a sequence of symbols, each symbol encoding a first symbol value and a second symbol value such that the data chirp signal includes a first symbol value sequence and a second symbol value sequence, the first and second symbol values being encoded via different properties of the symbol, the first symbol value sequence being selected from values in a primary predetermined sequence and a secondary predetermined sequence, the method including: selecting consecutive values of the first symbol value sequence from values in consecutive sequence positions of the primary predetermined sequence and the secondary predetermined sequence; encoding first data in the chirp signal via the selected first symbol value sequence; encoding second data in the chirp signal via the second symbol value sequence; and transmitting the data chirp signal to the receiver.

Abstract: A digital broadcasting receiving system is provided. A receiving module receives an M number of symbols each carrying an N number of subcarriers of a control signal. A converting module performs FFT on respective kth subcarriers of an ith symbol and an (i+1)th symbol to generate an (i, k)th converted value and an (i+1, k)th converted value. A demodulating module performs differential demodulation on the (i, k)th and (i+1, k)th converted values to generate an (i, k)th demodulation value. A combining module soft-combines the (i, 1)th demodulation value through the (i, N)th demodulation value to generate an ith prediction value corresponding to the ith symbol. A determining module identifies a synchronization segment in the control signal according to the 1st prediction value to the (M?1)th prediction value.

Abstract: A method for mitigating a multi-path-induced error in a global navigation satellite system comprises, for a respective measurement epoch, obtaining respective representations of a composite signal including a plurality of value-pairs of the composite signal. The method further comprises, with respect to the measurement epoch: obtaining a plurality of coefficients for a set of linear equations based on the plurality of value-pairs of the composite signal; iteratively obtaining solutions for the set of linear equations, thereby solving for a code tracking timing offset, a time delay of a multi-path signal of the composite signal relative to its direct-path signal, and orthogonal representations of the multi-path signal; determining a phase error between the composite signal and the direct-path signal, due to the time delay, in accordance with the orthogonal representations of the multi-path signal; and correcting for the code tracking timing offset and the phase error.

Abstract: A method for performing joint detection includes adjusting a ranking order of codes in a matched filtering result, and a ranking order of column vectors in a system submatrix according to the power. The joint detection is performed using an adjusted matched filtering result and an adjusted system submatrix, and acquires demodulated signals corresponding to the codes. The codes that have high power will be demodulated first. This ensures accuracy of demodulation, inhibits erroneous propagation effect, and improves accuracy of the joint detection.

Abstract: There is provided an incoherent UWB-IR communication method by which erroneous demodulation is difficult to occur even in a multipath environment. Thus, the present invention includes an incoherent wireless communication method including a first step of modulating transmission data, a second step of converting the modulated transmission data into pulses and converting the pulses received from the external into reception data, and a third step of demodulating the reception data, wherein the pulses used in the second step includes a plurality of pulse sequences and the plurality of pulse sequences is such that the peaks of cross-correlation values are lower than the peaks of autocorrelation values.

Abstract: Embodiments describe determining position by selecting a set of digital pseudorandom sequences. The magnitudes of the cross-correlation between any two sequences of the chosen set are below a specified threshold. A subset of digital pseudorandom sequences are selected from the set such that the magnitudes of the autocorrelation function of each member of the subset, within a specified region adjacent to the peak of the autocorrelation function, are equal to or less than a prescribed value. Each transmitter transmits a positioning signal, and at least a portion of the positioning signal is modulated with at least one member of the subset. At least two transmitters of the plurality of transmitters modulate respective positioning signals with different members of the subset of digital pseudorandom sequences.

Abstract: A method for detecting multi-user signals including conducting a first energy burst detection detecting a first plurality of user signals as a first energy burst, attempting to decode a user signal from the first plurality of signals within the first energy burst, cancelling out a first user signal from the first energy burst if the first user signal is successfully decoded from the first energy burst, determining a second user signal to be discarded if the second user signal is not successfully decoded from the first energy burst, conducting a second energy burst detection detecting a second plurality of signals as a second burst, and iteratively cancelling out the first user signal successfully decoded from the first energy burst from the second energy burst, wherein the second energy burst detection is conducted when all user signals within the first energy burst are either cancelled out or determined to be discarded.

Abstract: A method of detecting PN code synchronization for a DSSS signal comprising receiving a DSSS data signal of data frames comprised of I and Q symbols, at least a portion of each data frame comprising a unique word, demodulating the data signal into I and Q chip samples, filtering the I and Q chip samples and outputting the filtered I and Q chip samples to a chip stream controller which outputs the plurality of chip streams to a correlation matrix that correlates the plurality of chip streams with the chipped unique word and outputs a correlated data stream. A plurality of FFTs is run on the correlated output data stream and a processor searches for a maximum frequency bin power of each FFT. A PN synchronization detector searches for a maximum frequency bin power of each FFT. A PN synchronization detector searches for a maximum frequency bin power among the plurality of FFT rounds and determines whether PN synchronization is present.

Abstract: Systems and methods for improving performance in terrestrial and satellite positioning systems are disclosed. Signal processing systems and methods are described for selecting, from among a set of codes, certain codes having desired autocorrelation and/or cross-correlation properties. Systems and methods for generating, encoding, transmitting, and receiving signals using the selected codes are also described.

Abstract: Enhanced reception in a communication system is achieved by performing radio synchronization (SYNC) detection after multipath signal components are combined via a Rake combiner. In a communication system comprising a transmitter and a receiver, plural multipath signal components of a signal transmitted by the transmitter are received by the receiver. The plural multipath signal components are correlated with a known spreading code (e.g. a PN code). The correlated multipath signals are analyzed to identify plural correlation peaks and those correlation peaks that exceed a multipath threshold are selected. The selected correlation peaks are combined (i.e., coherently combined) to produce a combined signal. A synchronization event is declared when the combined signal exceeds an adjusted synchronization threshold and the combined signal is then decoded.

Abstract: A method and apparatus for determining operating modes in a receiver is described herein. A delay searcher in the receiver detects a signal image in the received signal. When the receiver is a RAKE receiver, a plurality of RAKE fingers coherently combine time-shifted versions of the received signal at different delays. Alternatively, when the receiver is a chip equalization receiver, an FIR filter coherently pre-combines the signal images in the received signal. A processor determines delays. In particular, the processor generates a first signal quality metric for a single-delay receiver mode, and generates a second signal quality metric for a multi-delay receiver mode. Based on a comparison of the first and second signal quality metrics, the processor selects the single-delay or the multi-delay receiver mode for processing the signal image.

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

Abstract: A receiver circuit provides improved noise estimation processing by at least partially removing receiver frequency error bias. An initial noise estimate is compensated using an error term based on the observed receiver frequency error, and the resulting compensated noise estimate can be used to improve other signal processing in the receiver. For example, the receiver may use compensated noise estimates to generate signal quality estimates, e.g., Signal-to-Interference (SIR) estimates, having improved accuracy. Additionally, or alternatively, the receiver may use the compensated noise estimates to generate RAKE combining weights having improved noise suppression characteristics. In an exemplary embodiment, the initial noise estimate is a noise correlation matrix generated from a received reference signal, e.g., pilot symbols, and the error term is an error matrix directly generated using the observed receiver frequency error and channel estimates taken from the reference signal.

Abstract: Methods and apparatus are disclosed for receiving a diversity transmitted signal using a Rake or G-Rake receiver in a radio system. Signals are diversity transmitted in a first and second symbol period by two or more antennas. One or more receive antennas receive the diverse transmit signals. Weights are generated to account for the correlation between the channels over which the diverse transmit signals are transmitted in the first and second symbol period and are used to weight the received signals. The weighted signals are then fed to a mutual receiver.

Abstract: A navigation system includes a correlation engine configured to despread a received signal. The correlation engine includes a correlator configured to evaluate the received signal against a replica signal to produce a correlation result, and a packet encoder configured to produce a packet comprising a destination address, a source address, and the correlation result. An input/output interface is configured to provide the packet to another component in the navigation system.

Abstract: An integrated circuit for facilitating spread spectrum reception of data having a data bit period includes an hypothesis search circuit (120, 210, 220) operable to correlate a pseudorandom code with a signal input based on a received signal to produce correlation results, and a processor circuit (320) operable to coherently integrate the correlation results over plural sample windows (PreD1, PreD2) staggered relative to each other in the coherent integration interval and to non-coherently combine the coherently integrated results corresponding to the plural sample windows (PreD1, PreD2) to produce a received signal output, whereby enhancing performance. Other circuits, receivers and processes are also disclosed.

Abstract: The present invention reduces the degradation in performance of one or more radio signals that are co-transmitted with a first radio signal from the same transmitting antenna in the same frequency channel and received by the same antenna due to multipath or other shared interference, where the one or more radio signals can be separated from the first radio signal. All received signals are coupled to the same adaptive array or adaptive filter to reduce multipath or other shared interference of the first radio signal, which reduces multipath and other shared interference in the other radio signals before they are separated and processed by their respective receivers, or the individual radio signals are separated before the first signal enters the adaptive array and coupled to a slave weighting network slaved to the weights of the adaptive array of the first signal to reduce interference in all the signals.

Abstract: A wireless communication system. The system comprises transmitter circuitry (BST1), the transmitter circuitry comprising encoder circuitry (50) for transmitting a plurality of frames (FR). Each of the plurality of frames comprises a primary synchronization code (PCS) and a second synchronization code (SSC). The encoder circuitry comprises of circuitry (501) for providing the primary synchronization code in response to a first sequence (32). The encoder circuitry further comprises circuitry (502) for providing the secondary synchronization code in response to a second sequence (54) and a third sequence (56). The second sequence is selected from a plurality of sequences. Each of the plurality of sequences is orthogonal with respect to all other sequences. The third sequence is a subset of bits from the first sequence.

Abstract: In this signal detection device (100), a delaying unit (101) delays a first distributed signal or a second distributed signal distributed from a received signal for a period of time of T1 to form a first multiplication signal, and delays the one for a period of time of T2 (T2>T1) to form a second multiplication signal. An integrator (104) calculates a first correlation value by integrating the result of multiplying the first distributed signal and the first multiplication signal. An integrator (105) calculates a second correlation value by integrating the result of multiplying the second distributed signal and the second multiplication signal. An evaluation unit (108) evaluates whether the signal to be detected, which is a periodic signal with a period of T1 or a periodic signal with a period of T2, exists or not, on the basis of the first correlation value and the second correlation value.

Abstract: A method of facilitating a user equipment (UE) communicating with a base station (BS) via a cell of a mobile communications system is disclosed. The UE selects a random access preamble sequence from a set of random access preamble sequences and transmits the random access preamble sequence to the BS. The BS receives the random access preamble sequence and estimates a time of arrival of the random access preamble sequence. A pre-defined set is used in generating the set of random access preamble sequences via at least one Zadoff-Chu sequence. The pre-defined set including all of the following values: 0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, 419.

Abstract: The invention relates to a method for compressing a wide band satellite radio-navigation signal in order to transmit it on a narrow band channel and to a method for calculating the correlation function of the spreading code of a satellite radio-navigation signal compressed by application of the compression method.

Abstract: A method is for decoding a pulse signal modulated through a transmitted reference modulation scheme. The modulated pulse signal may include, repetitively, a reference pulse followed by an information pulse delayed with a delay. The method may include subtracting or adding from the modulated pulse signal, a version of the modulated pulse signal delayed with the delay for obtaining a processed signal, and performing a non-coherent detection on the processed signal.

Abstract: A system that incorporates teachings of the subject disclosure may include, for example, a method for selecting a spectral region in a radio frequency spectrum for initiating a communication session having an uplink and a downlink, correlating a signal strength of portions of the spectral region to generate a correlation factor, detecting radio frequency interference in the spectral region according to the correlation factor, and generating tuning coefficient data to substantially suppress the radio frequency interference in the spectral region during the communication session. Other embodiments are disclosed.

Abstract: Techniques for use in sampling a signal of a receiver are described. In a sampling determination mode, a signal is sampled at a first sampling period for producing a sample set for each phase of the sampled signal. For each sample set, a correlation process is performed for producing a correlation result. One of the phases associated with an optimal correlation result is identified from the correlation results. In a communication mode, a received signal is sampled at a second sampling period at the phase associated with the optimal correlation result, for recovering user or signaling information from the received signal. The second sampling period is less than the first sampling period.

Abstract: A receiver unit of a communication device can employ multiple correlators for decoding the access address of a packet received from another communication device. A dynamically determined primary frequency offset is applied to a phase difference signal that is determined from an RF signal that comprises the packet. For each of a plurality of access address decoding chains of the receiver unit, a secondary frequency offset associated with the access address decoding chain is applied to the phase difference signal, the phase difference signal is correlated with a predetermined access address of the communication device, and a resultant correlation output is compared against a correlation threshold. One of the access address decoding chains that generated the correlation output that is greater than the correlation threshold is selected and the packet is demodulated based, at least in part, on the phase difference signal corresponding to the selected access address decoding chain.

Abstract: Embodiments of the present invention provide a multipath searching method and a multipath searcher, to improve accuracy of delay estimation, thereby improving performance of a receiver. The method includes: performing processing on received signals ri(t) and pilot sequences pi(t) to obtain upsampling signals y(?); subtracting contribution values of a current multipath waveform to other multipath waveforms by using a raised cosine function with a peak position set to zero and according to a global maximum value of |y(?)|2 and a total of M sampling points {circumflex over (?)}1(m) near the global maximum value, to obtain an upsampling signal yL(?) having a minimum residual in M groups of upsampling signals yL(m)(?); and obtaining a time delay power spectrum of the upsampling signal yL(?) having the minimum residual.