Abstract: The invention relates to a method and a system for estimating a symbol time error in a broadband transmission system, comprising: determination a time error signal of an output-signal of a discrete Fourier-transformation block (5) in a data symbol stream on the basis of intersymbol correlation using a predetermined period in each received symbol, selecting as a predetermined period last samples of a useful data part of an actual symbol and a preceding symbol after the discrete Fourier-transformation, determining the time error value (?) based on the intersymbol interference of the selected samples of the actual symbol and the preceding symbol.

Abstract: A method of generating a noisy receive signal for testing the performance of a mobile wireless communication device is described. A signal generator unit generates a transmit signal that frequency hops among a set of carrier frequency channels in a cyclic pattern having a time duration T. A wireless channel emulator unit generates a receive signal by modifying the transmit signal and also generates an interference signal by modifying the receive signal. The wireless channel emulator unit delays the interference signal relative to the receive signal by an integer multiple of the time duration T. The receive signal and the interference signal are combined by a combiner unit to generate the noisy receive signal.

Abstract: Provided are a method of decoding an LDPC code for producing several different decoders using a parity-check matrix of the LDPC code, and an LDPC code system including the same. The system includes: an LDPC encoder outputting an LDPC codeword through a channel; a first LDPC decoder decoding the LDPC codeword received through the channel, and when the decoding has failed in a second LDPC decoder, decoding the LDPC codeword according to original parity check matrix of the LDPC codeword, using soft information newly generated after the decoding is ended in the second LDPC decoder; and the second LDPC decoder, when the decoding has failed in the first LDPC decoder, receiving the soft information on each bit from the first LDPC, and decoding the LDPC codeword according to a new parity-check matrix produced from the parity-check matrix of the LDPC codeword using the received soft information on each bit.

Abstract: The invention relates to a method of estimating BEM coefficients of the Channel taps of a transmission Channel of an OFDM System having a given pilot arrangement, comprising, at the receiver side of the transmission Channel, the Steps of a) subsampling a received OFDM symbol in the frequency domain into a set of subsequences, b) inverse Fourier transforming each subsequence into a transformed subsequence, and c) estimating Fourier coefficients of a truncated Fourier series expansion model of the Channel taps from the set of transformed subsequences.

Abstract: A system of recovering information wide band signal comprising a receiver(s) for receiving data signal responses from a target area; the received data signal responses having information missing at a plurality of frequencies; at least one processor for recovery of data from the data signal responses operatively connected to the receiver(s); a first memory comprising time-shifted responses based upon the wide band signal response, a second memory comprising a plurality of spectrally filtered time-shifted responses; whereby the first and second memories operate to provide data to the at least one processor compensate for the information missing at the plurality of frequencies.

Abstract: Systems, processes, and structures provide near-field transmit power measurement for MIMO wireless devices (DUT), such as for any of product development, product verification, and/or production testing. A test signal, such as comprising a pulse train signal, is provided to a MIMO device under test (DUT), wherein portions of the test signal controllably steered and sequentially transmitted from each of the device antennas, to one or more test antennas that are positioned in close proximity to the MIMO DUT. The near-field power of the received test signals is measured, to quickly and efficiently determine if one or more data streams of the MIMO DUT has a problem.

Abstract: A processor link that couples a first processor and a second processor is selected for validation and a plurality of communication parameter settings associated with the first and the second processors is identified. The first and the second processors are successively configured with each of the communication parameter settings. One or more test data pattern(s) are provided from the first processor to the second processor in accordance with the communication parameter setting. Performance measurements associated with the selected processor link and with the communication parameter setting are determined based, at least in part, on the test data pattern as received at the second processor. One of the communication parameter settings that is associated with the highest performance measurements is selected. The selected communication parameter setting is applied to the first and the second processors for subsequent communication between the first and the second processors via the processor link.

Abstract: It is disclosed a method including transmitting indication information indicating network cells of a first type different from network cells of a second type, the transmitting including a) broadcasting control information, the indication information to be transmitted being an indication flag, b) assigning a set of synchronization information to the network cells of the first type, and broadcasting control information, the indication information to be transmitted being the synchronization information, c) reserving at least one signaling code information for the network cells of the first type, the indication information to be transmitted being the signaling code information, d) transmitting signaling information subjected to modulation by at least one predefined phase modulation or scrambling by at least one predefined scrambling sequence, the modulation or scrambling being indicative of network cells of the first and second types, and/or e) transmitting i) a PSS and a RS, ii) a SSS and a RS, or iii) a PSS and

Abstract: A multipath channel emulation system and method are disclosed. In some aspects, the system and method allow for analog emulation of a multipath MIMO wireless channel. Such multipath channel emulation system is used for testing the ability of wireless communication devices to operate in an airlink channel characterized by multipath. In a particular aspect, an impedance mismatch or discontinuity is provided in an open-ended coaxial cable so as to cause multiple back and forth reflections between an impedance discontinuity and an open coaxial cable stub and, optionally, including a delay element to emulate a multi-cluster multipath environment. A plurality of such stub subsystems may be combined as sub-paths in a multipath channel emulator.

Abstract: Described are systems and methods of determining DC offset voltages in IQ modulators. First, two different DC test voltages are selected for one of the inputs to the IQ modulator. Then, a first test voltage is applied to one input to the IQ modulator while test data is generated by measuring outputs from a set of signals applied to the other input to the IQ modulator. Then the second test voltage is applied and another set of test data generated. From the first and second sets of test data, second-order polynomial functions may be constructed and compared to one another to yield a ratio of power value outputs. Then the DC offset voltages may be determined from the ratio of power value outputs.

Abstract: An apparatus, method, computer readable medium, and system are provided to generate a symbol placement associated with a transmission scheme by transforming a retrieved set of equalization coefficients. Symbols included in the symbol placement may be analyzed and quantified in terms of their distance from a decision boundary. Symbols may be synthesized on an iterative basis in order to obtain visibility into the underlying performance of the transmission scheme over time. If equalization is unable to reduce a signal impairment below a threshold value within a predetermined amount of time, then a determination may be made that a non-linear distortion source is present in a network or communication system. Signals received from a plurality of user terminals may be compared with one another in order to determine a probable location or cause of the non-linear distortion.

Abstract: A concurrent multi-band linearized transmitter (CMLT) has a concurrent digital multi-band predistortion block (CDMPB) and a concurrent multi-band transmitter (CMT) connected to the CDMPB. The CDMPB can have a plurality of digital baseband signal predistorter blocks (DBSPBs), an analyzing and modeling (A&M) stage, and a signal observation feedback loop. Each DBSPB can have a plurality of inputs, each corresponding to a single frequency band of the multi-band input signal, and its output corresponding to a single frequency band; each output connect corresponding to an input of the CMLT. The A&M stage can have a plurality of outputs connected to and updating the parameters of the DBSPBs, and a plurality of inputs connected to either both outputs of the signal observation loop or the output of the subsampling loop and to outputs of the DBSPBs. The A&M stage can perform signals' time alignment, reconstruction of signals and compute parameters of DBSPBs.

Abstract: An apparatus and a method are described for envelope detection used in fields including voice processing, image processing, data communication, and energy/data transmission. The apparatus and the method for envelope detection eliminate a carrier component from a modulated signal by performing a square-sum operation between two adjacent sampling signals among signals sampled from the modulated signal. The apparatus and the method detect an envelope of the modulated signal from the modulated signal in which the carrier component is eliminated.

Abstract: Residual FEXT resulting from intended and/or inherent partial cancellation of crosstalk in vectored DSL systems impairs upstream power back-off (UPBO) as traditionally implemented. By considering and taking into account the effects of residual crosstalk on vectored DSL system performance and operation, improved data rates and/or other vectored DSL system performance are realized through the use of UPBO parameters generated for a given residual FEXT environment.

Abstract: Systems and methods for performing phase tracking scheme for an Analog to Digital converter based tuner. In many embodiments, a phase tracking scheme is used that includes a phase locked loop that corrects the phase of the output signals and an amplitude modulation compensator that modulates the amplitude of the output digital signals to compensate for phase noise based upon the received output digital signals.

Abstract: To provide a mobile communication terminal test device that can generate a signal with amplitude-frequency characteristics or phase-frequency characteristics which are changed over time. A mobile communication terminal test device 10 includes a data generation unit 12 that generates a bit stream, a sub-carrier generation unit 31 that receives bit stream data and performs, for example, predetermined encoding, symbol mapping, or sub-carrier mapping to convert the received data into a plurality of sub-carriers based on an OFDM modulation system, a frequency characteristic storage unit 13 that stores table data for predetermined amplitude-frequency characteristics and phase-frequency characteristics, and a frequency characteristic calculation unit 32 that sets the amplitude and phase of each sub-carrier input from the sub-carrier generation unit 31 on the basis of the table data.

Abstract: A system and methods for optimizing the performance of communication network utilizing an electrical distribution grid are disclosed. Optimization methods may include archiving historical message data and metrics from transmissions by Remote Hubs received on one or more Substation-to-Edge channels. Trends in the archived metrics over time are later analyzed to determine which combination of transmission variables such as frequency band, modulation method, drive voltage, and transmission time produce the highest message success rates overall. The results of such analysis may be used to provide feedback to the Remote Hubs or reveal necessary repairs to the network. Optimization may also be carried out locally by an individual Remote Hub by estimating the impedance of the transmission medium and adjusting either drive voltage or transmission band.

Abstract: A method and apparatus for characterized pre-distortion calibration is provided. The method begins with the selection of a number of devices to be characterized. The number of devices selected may be a subset of a larger group of devices. The selected number of devices is then characterized. The method avoids characterizing the large group of devices. The apparatus includes a processor for performing pre-distortion calibration, a processor for averaging curves for each RF gain index on each channel, and a non-volatile memory.

Abstract: In described embodiments, data pattern-based detection of loss of signal (LOS) is employed for a receive path of serializer/deserializer (SerDes) devices. Pattern-based LOS detection allows for detection of data loss over variety of types of connection media, and is generally insensitive to signal attenuation. More specifically, some described embodiments disclose reliable pattern-based detection of LOS across different connection media for incoming receive data when discreet time decision feedback equalization (DFE) is employed.

Abstract: A method and apparatus for dynamically adjusting power of a transmitter is herein described. A transmitter transmits a pattern to a receiver at a differential voltage. The length of the pattern, in one embodiment, is selected to be a reasonable length training pattern, as not to incur an extremely long training phase. If errors are detected at the receiver in the pattern, the transmitter steps the differential voltage until errors are not detected in the pattern at the receiver. The differential voltage, where no errors are detected, is scaled by a proportion of a target confidence level to a measured confidence level associated with the reasonable length training pattern. As a result, a training phase is potentially reduced and power is saved while not sacrificing confidence levels in error rates in the data exchange between the transmitter and receiver.

Abstract: A receiver device detects a plurality of symbols in a signal and determines, based on the one of the plurality of detected symbols, an estimated beginning of a subsequent frame. The receiver device determines whether the estimated start of the subsequent frame corresponds to an actual start of the subsequent frame. When the estimated start of the subsequent frame corresponds to the actual start of the subsequent frame, the receiver is synchronized to the actual start of the frame. When the estimated start of the subsequent frame does not corresponds to the actual start of the subsequent frame, the receiver device determines, based on a further one of the plurality of detected symbols, an estimated beginning of another subsequent frame. The receiver device determines whether the estimated start of the other subsequent frame corresponds to an actual start of the other subsequent frame.

Abstract: A method for supporting wireless communication over a physical channel in a mobile broadband system includes providing an estimate of the channel and obtaining a channel autocorrelation function of a channel impulse response of the channel. The method also includes expressing the channel autocorrelation function as a zero order Bessel function and applying Taylor expansion to the zero order Bessel function. Additionally, the method includes performing derivation of the channel autocorrelation function to obtain an estimate of the maximum Doppler frequency and using the obtained estimate of the maximum Doppler frequency to compensate for a current Doppler effect in a receiver receiving the signals.

Abstract: A method for facilitating wireless testing of a radio frequency (RF) signal transceiver device under test (DUT). Using multiple antennas within a shielded enclosure containing the DUT, multiple wireless RF test signals resulting from a RF test signal radiated from the DUT are captured and their respective signal phases are controlled prior to being combined to form a composite RF signal. This process is repeated until power level differences between signal power levels at respective pairs of a selected number of RF signal frequencies have values between predetermined minimum and maximum values, thereby providing compensation for the multipath signal environment within the shielded enclosure, and thereby simulating a wired test signal path during wireless testing of the DUT.

Abstract: A signal quality measuring apparatus includes a binary signal generating unit to generate a binary signal from an input signal; a level information extracting unit to extract level information from a relationship between the input signal and the binary signal using at least two window lengths; and a quality calculating unit to calculate a quality of the input signal based on the level information.

Abstract: There is provided a peak suppressor including a first peak position detector to detect a first time when amplitude of a transmission signal changes in a convex manner and exceeds a specific level as a first peak position, a second peak position detector to detect a second time that is different by a predetermined time from the first peak position when the amplitude of the transmission signal exceeds the specific level as a second peak position, a suppression signal generator to generate a suppression signal for suppressing the amplitude of the transmission signal to a value that is equal to or lower than the specific level, based on amplitude and phase of the transmission signal corresponding to the first and second peak positions detected by the first and second peak position detectors, and an adder to add the suppression signal generated by the suppression signal generator to the transmission signal.

Abstract: A frequency response signal transmitting device for frequency response measurement includes: a first oscillator unit configured to generate a clock signal; a clock and data recovery (CDR) unit configured to remove a jitter component of the clock signal; a pulse signal generation unit configured to receive an output signal of the CDR unit and generate a pulse signal repeated at a predetermined period; and an optical signal transmission unit configured to receive the output signal of the CDR unit and apply the received signal to an optical cable.

Abstract: Techniques for enabling an estimate of a transmittal signal vector, given a received signal vector and a channel matrix to be computed, are provided. An initial solution signal vector for the estimate is calculated, and based on the initial estimate, a pool of possible solutions is generated. Methods described herein may be iterative in nature, and may cycle through possible estimates of the transmitted signal vector so as to continually improve the estimates and the pool of possible estimates. The methods may terminate once stopping criteria are reached. In some example methods, solutions may be marked at taboo and a taboo period can be established that indicates a number of subsequent iterations for which the current solution signal vector cannot be considered.

Abstract: Provided is a radio relay station which relays data transmitted and received by a radio base station a radio terminal in a radio communication system which employs the TDD scheme. The radio relay station receives data from the radio base station during a downlink subframe period and transmits data to the radio base station during an uplink subframe period. The radio relay station sets a remote side transmission period for transmitting data to the radio terminal in the uplink subframe period and sets a remote side reception period for receiving data from the radio terminal in the downlink subframe period.

Abstract: In accordance with an example embodiment, there is disclosed herein a coexistence mechanism for multiple channels. A plurality of channels are monitored to determine which channels are available for communications. Upon receiving a request to establish communications on a channel set within the plurality of channels, a response is sent to the request on at least one in the channel set. The response comprises data representative of which channels from the channel set are available for communications. Optionally, the response may include data indicating how long the unavailable channels will be occupied.

Abstract: In a differential signal test mode, the first control circuit causes, in response to the first control signal, the differential signal generating circuit to generate the differential signal depending upon the data signal and output the differential signal. The second control circuit stops the operation of the common mode signal generating circuit in response to the second control signal. In a common mode signal test mode, the first control circuit causes, in response to the first control signal, the differential signal generating circuit to generate a fixed differential signal and output the differential signal. The second control circuit causes, in response to the second control signal, the common mode signal generating circuit to generate the common mode signal depending upon the clock signal and output the common mode signal.

Abstract: A method of checking an error vector magnitude of transmitter in accordance with some embodiments of the inventive concept may include dividing a transmission baseband signal which the transmitter transmits into a plurality of processing units; performing a transmitter function and an ideal receiver function with respect to each of the plurality of processing units; generating a reception baseband signal by recombining a processing result of each of the plurality of processing units; and calculating an error vector magnitude (EVM) by comparing the transmission baseband signal with the reception baseband signal. A simplified method of checking an error vector magnitude of transmitter in accordance with some embodiments of the inventive concept may include generating symbols composed of only pilots; generating symbol composed of only data; and checking an error vector magnitude (EVM) using the all the symbols.

Abstract: Through the use of a least squares minimization concept, the loop length, the number of bridged taps and length of the bridged taps on a transmission line can be determined from readily available modem data. In particular, the loop length, the number of bridge taps and the length of bridged taps can be estimated by comparing a measured frequency domain channel impulse response of the transmission line to a model of a loop that is comprised of multiple sections and multiple bridge taps.

Abstract: Apparatus for processing broadband impulses signals of low repetition rate includes a tuner for receiving broadband impulsive signals of low repetition rate and providing an output signal characteristic of the amplitude and spectral content of the received input signal. Resolution bandwidth filters coupled to the tuner output each have a different bandwidth that determines the measurement resolution and influences the sensitivity and transient response to low repetition rate impulsive signals. At least one radio frequency switch selects a resolution bandwidth filter for coupling to and associated one of at least a peak detector, an average detector and an envelope generator. A gate generator coupled to the peak detector, the average detector and the envelope generator furnishes a gating signal to each to provide a peak signal, an average signal and an envelope signal respectively during a selected gating interval. A microprocessor is coupled to the peak detector and the average detector.

Abstract: Method and apparatus for medium access control in a wireless broadband system with multiuser MIMO/MISO technology comprising the steps of a transmitter (Tx) broadcasting a polling message (1) to all the users (Rx1 . . . Rxi . . . RXN) associated to said transmitter (Tx); the users answering with reply messages (2) during a time slot (61 . . . 6m) randomly selected from a plurality of time slots in which a period of time dedicated to sending reply messages (5) is divided; the transmitter (Tx) performing a scheduling and transmission of data (3); and scheduled users sending Acknowledgment messages (4). Preferably, only users which measure a Signal to Noise plus Interference Ratio over a pre-defined threshold for a transmission beam send reply messages (2).

Abstract: A synchronization method for current differential protection comprises: selecting a point on the transmission line protected by the current differential protection; measuring the current and the voltage of each of the terminals of said transmission line; calculating the compensating voltage at the selected point respectively according to the measured current and the voltage of the each terminal; detecting and calculating the synchronization error by comparing all the compensating voltages.

Abstract: The present invention includes receiving a signal from an output of a dispersive communication channel established between a transmitter and a receiver, determining normalized Nyquist energy of the signal transmitted along the dispersive communication channel established between the transmitter and the receiver, and generating a mapping table configured to identify peaking value at or above a selected tolerance level at or near the Nyquist frequency for a signal received by the receiver based on the normalized Nyquist energy.

Abstract: The subject matter discloses an apparatus residing within an RF chip, comprising: a detection unit for detecting IQ mismatch in an IQ signal; an analog calibration module comprising a first analog calibration mechanism for calibrating IQ mismatch in the phase component and a second analog calibration mechanism for calibrating IQ mismatch in the amplitude component; and a control unit for determining a calibration sequence of the IQ signal.

Abstract: Automatic gain control in a receiver. A method for controlling operating range of an analog-to-digital converter (ADC) by an automatic gain control circuit includes estimating a peak-to-average ratio corresponding to an analog signal from digital samples of the analog signal. The method includes determining a peak value corresponding to the analog signal based on the peak-to-average ratio. Further, the method includes maintaining magnitude of the analog signal at an input of the ADC and gain of the receiver based on the peak value.

Abstract: A sampling phase selection method for a data stream is provided, wherein the data stream has a variable data rate in a fixed time period. The method comprises generating a calibration signal, wherein the time interval of the calibration signal is longer than the fixed time period of the data stream, generating a first clock sequence and a subsequent second clock sequence, wherein the first and the second clock sequence are composed of a plurality of continuous clock phases and the number of the clock phases of the first clock sequence are the same as that of the clock phases of the second clock sequence, selecting one of the phases of the first and the second clock sequence, in turn, to provide a sampling phase, performing a plurality of samplings on the data stream to generate a flag signal, and selecting a final sampling phase according to the flag signals with different sampling phases.

Abstract: A communications device includes an input that receives a communications signal having in-phase (I) and Quadrature (Q) signal components. A bit synchronization circuit detects the symbol timing error in the communications signal and includes a symbol mapper circuit configured to receive I and Q signal components and determine transition samples of vectors within the signal constellation. A rotation generator circuit is coupled to the symbol mapper circuit and configured to rotate the trajectory of the transition samples at their midpoints to determine the symbol timing error.

Abstract: A multiple input multiple output (MIMO) antenna module, comprising a first signal feed port coupled to a first antenna element disposed along a first edge of a PCB, a second signal feed port coupled to a second antenna element disposed on the PCB and a transceiver operable to be selectively coupled to either or both of the first and second signal feed ports. The first and second antenna elements form a plurality of antenna elements confined to a peripheral section surrounding a central region of the PCB of the MIMO antenna module.

Abstract: A method of receiving a data transmission includes detecting a first switching of a transmission signal to a first signal value, starting a duration measurement of a first time interval that begins with detecting the first switching of the transmission signal, detecting a second switching of the transmission signal to a second signal value, stopping the measurement of the first time interval duration and starting a second duration measurement of a second time interval, detecting a third switching of the transmission signal to the first signal value or to a third signal value, stopping the second measurement in response to detecting the third switching, determining a relation of the first and second time interval durations from the first and second measurements, and determining a data value of the transmission signal based on the determined relation.

Abstract: Various systems and methods for comparing media signals are disclosed. In some embodiments, media signals are compared by identifying characteristic features in the respective signals and then analyzing the characteristic features to determine if the signals contain corresponding content. In other embodiments, the characteristic features are analyzed to determine the extent to which the signals are synchronized in time.

Abstract: This disclosure relates to radio frequency (RF) functional testing of transceivers of wireless devices.

Abstract: A signal delay estimator includes an adjustable delay element for delaying a first signal to obtain a delayed first signal, a delay amount estimator for estimating a delay amount between the delayed first signal and a second signal that is similar and delayed relative to the first signal, and a leading signal determiner for determining whether the delayed first signal leads the second signal or vice versa, and for generating a corresponding binary signal. A selective inverter is provided for selectively inverting the delay amount depending on the binary signal. The signal delay estimator also includes a feedback element to the adjustable delay element for controlling a delay based on an output of the selective inverter. Another exemplary signal delay estimator includes a closed control loop with an adjustable delay element and separate first and second processing paths for absolute delay amount and delay direction, respectively.

Abstract: A method for testing data packet reception characteristics, such as sensitivity and throughput, of a data packet signal transceiver. By monitoring responsive data packet signals returning from a device under test (DUT), it can be determined whether and when the DUT has successfully received valid data packets, received faulty data packets, received valid data packets in a faulty manner, or not received valid data packets. When any of such events are detected, the stimulus data packet signals can be provided in such a manner as to determine whether possible DUT reception problems are related to power level, duration or data rate of the stimulus data packet signals, or to circuitry within DUT without requiring external controls over or querying of the DUT.

Abstract: A transmitting device may determine a physical layer transmission properties based upon an amount of data to transmit via a communications channel. The physical layer transmission properties may comprise a derated tone map that has a lower physical layer transmission throughput capability than an original tone map. An indication regarding the derated tone map may be included in a first message, a portion of a physical layer framing protocol, a physical layer control transmission (such as a frame control symbol), or other transmissions such that the receiving device can derive the derated tone map without significant added overhead.

Abstract: Systems and methods for measuring transmitter and/or receiver I/Q impairments are disclosed, including iterative methods for measuring transmitter I/Q impairments using shared local oscillators, iterative methods for measuring transmitter I/Q impairments using intentionally-offset local oscillators, and methods for measuring receiver I/Q impairments. Also disclosed are methods for computing I/Q impairments from a sampled complex signal, methods for computing DC properties of a signal path between the transmitter and receiver, and methods for transforming I/Q impairments through a linear system.

Abstract: A transmitter includes an input, a modulator, and a calibration memory configured to store discrete calibration test points. A compensator is coupled between the input and the modulator and cooperates with the calibration memory to cause the modulator to generate a respective calibration carrier signal for each of the discrete calibration test points during a calibration phase. A detector is coupled to an output of the modulator and is configured to determine respective calibration values of the calibration carrier signals during the calibration phase. A compensator calculator is coupled to an output of the detector, and is configured to generate compensation values for the compensator for use during an operation phase and based on the calibration values of the calibration carrier signals.

Abstract: A PAPR determining device includes a detecting unit and a PAPR determining unit. The detecting unit detects a predetermined value's changes, which is a cause of changes in a saturation power of a power amplifier. When the detecting unit detects any change in the predetermined value, the PAPR determining unit determines a PAPR value that corresponds to the saturation power of the power amplifier.