Signal Noise Patents (Class 375/227)
  • Publication number: 20090003425
    Abstract: A system for measuring inter-carrier interference (ICI) in an OFDM system includes a test symbol generator coupled to a transmitter of the OFDM system to generate an N*N orthogonal matrix having N*N test symbols, and to send the test symbols in a test symbol stream via the transmitter to a receiver of the OFDM system. The N*N test symbols are arranged by the test symbol generator into an N*N orthogonal matrix before being sent to the receiver. The system also includes an ICI measuring module coupled to the receiver to detect the N*N test symbols received in the receiver and to arrange the test symbols as a receiving matrix in the same way as the orthogonal matrix in the transmitter. The ICI measuring module outputs the receiving matrix as an ICI matrix of the OFDM system, wherein an element on the kth row, lth column of the ICI matrix represents interference from the lth sub-carrier on the kth sub-carrier, wherein k?l.
    Type: Application
    Filed: April 1, 2008
    Publication date: January 1, 2009
    Inventors: Danxun Shen, Hong Wei Kong, Xu Zhao
  • Publication number: 20090003426
    Abstract: A transmitting and receiving unit is provided for a field device for measuring a filling level or a pressure, which has an adaptive error counter. In this way, the sensitivity of the error detection may be adapted to individual needs or to the present length of the communications section. Thus, during wireless communication an optimally set error counter may fundamentally be used according to the distance to be covered without any adjustment needing to be made for this on the user side.
    Type: Application
    Filed: May 27, 2008
    Publication date: January 1, 2009
    Inventor: Andreas ISENMANN
  • Publication number: 20080317111
    Abstract: This application is concerned with a non-intrusive video quality measurement method, in particular where the video signal having: an original form; encoded form in which video signal has been encoded using a compression algorithm utilising a variable quantiser step size such that the encoded signal includes a quantiser step size parameter; and, a decoded form in which the encoded video signal has been at least in part reconverted to the original form. The method comprises the steps of: a) generating a first quality measure which is a function of said quantiser step size parameter; b) generating a second quality measure which is a function of the spatial complexity of the frames represented by the video signal in the decoded form; and, c) combining the first and second measures in order to obtain an estimate for the subjective visual quality of the decoded video.
    Type: Application
    Filed: November 7, 2006
    Publication date: December 25, 2008
    Inventor: Andrew G Davis
  • Publication number: 20080310490
    Abstract: A signal generator generates amplitude noise on a selected segment of a test signal. A user interface is used for selecting a segment of the test signal and an associated power level for applying amplitude noise at a selected power level to the test signal segment. A signal processing unit compiles the selected power level of the selected segment with the test signal to generate digital data representative of the test signal with selected segments having amplitude noise. A waveform generator receives the digital data and generating a test signal output having amplitude noise at selected segments of the test signal. The method includes the steps of: selecting a segment of the test signal to add amplitude noise; selecting a power level for the amplitude noise; and applying the amplitude noise at the selected power level to the selected segment of the test signal.
    Type: Application
    Filed: June 11, 2008
    Publication date: December 18, 2008
    Applicant: TEKTRONIX INTERNATIONAL SALES GMBH
    Inventors: Kunihisa Jitsuno, Susan C. Adam, Muralidharan Karapattu
  • Patent number: 7466749
    Abstract: Rate selection with margin sharing in a system with independent data stream rates is presented. Signal-to-Noise Ratio (SNR) estimates are obtained for each stream. Rates are selected for the streams based on the SNR estimates, such that at least one data stream has an SNR margin below a threshold, each remaining data stream has an SNR margin above a respective threshold, and the total SNR margin for all streams is above a total threshold. For rate selection with margin sharing with a vector-quantized rate set, SNR estimates are obtained for usable transmission channels. The total SNR margin is determined for each rate combination based on the estimates. Each rate combination is associated with a specific number of data streams to transmit, a specific rate for each data stream, and a specific overall throughput. The combination with the highest overall throughput and non-negative total SNR margin is selected.
    Type: Grant
    Filed: May 12, 2005
    Date of Patent: December 16, 2008
    Assignee: QUALCOMM Incorporated
    Inventors: Irina Medvedev, Jay Rodney Walton
  • Patent number: 7463677
    Abstract: The present invention implements a method and system for dynamically adapting the modulation and coding scheme for radio links in a wireless communications network based on a retransmission environment model in order to maximize throughput and most efficiently allocate bandwidth resources. The present invention encompasses a refined calculus and methodology for deriving the link adaptation thresholds in a retransmission environment using a complex model and analysis of the retransmission environment. The present invention holds particular application for wireless data communications as opposed to real time data services because it is based on a retransmission model applicable primarily for data services. A critical component of this new link adaptation system is a “no transmission” cutoff mode that is selected for SIR below a base threshold value. This new mode prevents system instability and misallocation of bandwidth in a wireless communication system.
    Type: Grant
    Filed: October 22, 2004
    Date of Patent: December 9, 2008
    Assignee: AT&T Corp.
    Inventors: Justin Che-I Chuang, Xiaoxin Qiu
  • Publication number: 20080298449
    Abstract: At least one property of a measuring apparatus that is different property from the error vector magnitude is measured, or a previously measured value or a predetermined value of the at least one property is prepared; based on the measured value or specification value of each of the at least one property, each corresponding noise power within a specific frequency range is found; and the error vector magnitude is calculated based on the noise power.
    Type: Application
    Filed: May 30, 2007
    Publication date: December 4, 2008
    Inventors: Mitsuru Yokoyama, Kenji Miki
  • Publication number: 20080298450
    Abstract: A system, apparatus and method is disclosed for multiband wireless communication. Frequency bands and/or transmission formats are identified as available within a range for wireless communication. Signal quality metrics for each frequency band are evaluated by a receiver to identify qualified frequency bands. The qualified frequency bands can be ranked according to one or more signal quality metrics, where the list of qualified bands can be communicated to a transmitter. The transmitter is arranged to evaluate the list of qualified bands and select a communication method based on the available frequency bands and a selected communication optimization scenario. Multiple frequency bands and communication methods can be utilized by the transmitter such that a combination of licensed, unlicensed, semilicensed, and overlapped frequency bands can be simultaneously used for communication.
    Type: Application
    Filed: July 21, 2006
    Publication date: December 4, 2008
    Inventors: Hongliang Zhang, Mark McDiarmid
  • Publication number: 20080298451
    Abstract: An apparatus and method for estimating a Carrier-to-Interference and Noise Ratio (CINR) in a communication system are provided.
    Type: Application
    Filed: May 27, 2008
    Publication date: December 4, 2008
    Applicant: SAMSUNG ELECTRONICS CO. LTD.
    Inventors: Byoung Ha YI, Ki-Young HAN
  • Patent number: 7460619
    Abstract: A method and system for optimizing coding gain that alters the backsearch buffer length and/or the input buffer length of a decoder in response to one or more transmission performance characteristics of the system. The performance characteristics are monitored to determine the performance of the system. The measured transmission performance characteristics are used to control the lengths of the backsearch buffer and the input buffer. The measured transmission performance characteristics along with the backsearch length and/or the input buffer length are analyzed and compared with simulated decoding results. In accordance with the simulated results, the system determines the optimal size of the backsearch buffer and the input buffer needed to achieve a desired performance target. The system adjusts the size of the backsearch buffer length and/or the input buffer length to equal the determined optimal lengths.
    Type: Grant
    Filed: March 21, 2005
    Date of Patent: December 2, 2008
    Assignee: AT&T Intellectual Property I, L.P.
    Inventors: Thomas J J Starr, Michael John Rude, Joseph Martin Charboneau
  • Patent number: 7460591
    Abstract: Measurement of jitter in a system uses a digital test sequence including many repetitions of a test pattern. An Acquisition Record is made of the entire test sequence. A complete Time Interval Error (TIE) Record is made of the Acquisition Record. The complete TIE Record is separated into a collection of Component TIE Records, one for each transition in the test pattern, and that collectively contain all the different instances in the test sequence of that transition in the test pattern. An FFT is performed on each component TIE Record, and the component FFTs are processed to obtain timing jitter data for the digital signal.
    Type: Grant
    Filed: August 30, 2004
    Date of Patent: December 2, 2008
    Assignee: Agilent Technologies, Inc.
    Inventors: Steven D. Draving, Allen Montijo
  • Patent number: 7460967
    Abstract: Events discovered by an automatic measurement subsystem in the trace of a DSO are visited using a set of event navigation controls. In a TIME Mode the controls operate to display the first of those events, display the next event after the one currently displayed, display the previous event before the one currently displayed, and, display the last event. In a SEVERITY Mode the controls operate to display the best of those events, display the next best event relative to the one currently displayed, display the next worst event before the one currently displayed, and, display the worst event. The sets of navigation controls may be a mode control menu accompanied by four stylized arrow shaped buttons within a GUI that are clicked on by an operator using a mouse. One set of arrow shaped button can serve both modes, or different sets of buttons can serve each respective mode.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: December 2, 2008
    Assignee: Agilent Technologies, Inc.
    Inventor: Christopher P Duff
  • Publication number: 20080291990
    Abstract: A reception quality measuring apparatus of the present invention comprises a first sub-carrier averaging unit for averaging and outputting a channel gain after equalization estimated on the basis of the pilot signal over a sub-carrier, a first power calculation unit for calculating the power of a signal output from the first sub-carrier averaging unit and outputting the same as signal power, a pilot replica generator for generating and outputting a pilot signal replica with respect to a zero-timing signal component based on the zero-timing signal component when a signal x(n) in the time domain after equalization corresponding to the equalized signal is n=0, and also based on a previously set pilot code characteristic, a subtractor for subtracting the pilot signal replica output from the pilot replica generator from the equalized signal and outputting the result as an interference signal, a second power calculation unit for calculating and outputting the power of the interference signal output from the subtrac
    Type: Application
    Filed: May 12, 2008
    Publication date: November 27, 2008
    Applicant: NEC CORPORATION
    Inventors: Shousei Yoshida, Masayuki Kimata
  • Patent number: 7457350
    Abstract: Described herein are ultra wideband (UWB) receiver systems, and applications thereof. Such a UWB receiver includes a receiver front end and a correlator coupled to the receiver front end. The receiver front end is configured to receive a UWB signal having a plurality of multipath components. The correlator is configured to correlate the UWB signal with a reference signal. The UWB signal includes a plurality of pulses, wherein each pulse has a plurality of multipath components. The reference signal also includes a plurality of multipath components of the pulse. The correlator includes at least one correlator module configured to correlate a plurality of the multipath components of the pulse with the reference signal.
    Type: Grant
    Filed: July 19, 2004
    Date of Patent: November 25, 2008
    Assignee: Artimi Ltd.
    Inventors: David Baker, Mark Justin Moore
  • Patent number: 7453934
    Abstract: The present invention provides a method for automatic calibration of a signal path in receivers (e.g., radio frequency receivers) using a noise (and not a specific test signal) as a source and a fast Fourier transform (FFT) of the noise for correcting various parameters related to an inphase/quadrature (I/Q) imbalance in a frequency domain. The present invention (method and apparatus) can provide detecting and correcting an I/Q phase error, an I/Q amplitude error, an absolute corner frequency of the analog baseband filter, and a relative corner frequency of the analog baseband filters just by using the noise as a stimuli. This calibration can be used for a factory calibration or it can be used as an on-site calibration for base stations. Mobile devices can calibrate themselves independently of their location. This reduces the requirements for the test equipment in the manufacturing and maintenance stages.
    Type: Grant
    Filed: June 27, 2005
    Date of Patent: November 18, 2008
    Assignee: Nokia Corporation
    Inventors: Pauli Seppinen, Julius Koskela, Mikael Gustafsson
  • Patent number: 7453963
    Abstract: A common problem in audio processing is that a useful signal is disturbed by one or more sinusoidal noises that should be suppressed. One embodiment of the invention provides a method of canceling a sinusoidal disturbance of unknown frequency in a disturbed useful signal. The method comprises the steps of estimating parameters of the sinusoidal disturbance including amplitude, phase and frequency; generating a reference signal on the basis of the estimated parameters; and subtracting the reference signal from the disturbed useful signal. According to one embodiment of the present invention, the estimation is performed by an Extended Kalman filter.
    Type: Grant
    Filed: May 25, 2005
    Date of Patent: November 18, 2008
    Assignee: Honda Research Institute Europe GmbH
    Inventors: Frank Joublin, Martin Heckmann, Björn Schölling
  • Patent number: 7453933
    Abstract: In the method of estimating a signal-to-interference+noise ratio (SINR), either the polarities or bit values of a plurality of received data symbol samples are estimated. Then an SINR estimate is generated based on the plurality of received data symbol samples and the estimated polarities or bit values of the plurality of received data symbol samples such that the SINR estimate is not substantially dependent on the polarities or a bit value of the plurality of received data symbol samples.
    Type: Grant
    Filed: May 4, 2001
    Date of Patent: November 18, 2008
    Assignee: Lucent Technologies Inc.
    Inventors: Daniel R. Jeske, Pantelis Monogioudis, Kiran M. Rege, Ashwin Sampath
  • Publication number: 20080279268
    Abstract: The frequency of signals under test is stabilized and the noise components of the signals under test whose frequency has been stabilized is measured. When the noise of the object under test is related to frequency or phase, the measured noise components are corrected based on the properties of frequency stabilization.
    Type: Application
    Filed: May 10, 2007
    Publication date: November 13, 2008
    Inventors: Junichi Iwai, Koji Murata
  • Publication number: 20080279269
    Abstract: Systems and methods for performing loop termination are described. One embodiment is a method that comprises receiving a per-port calibrated echo signal of a loop under test, receiving a region designation and a loop length for the loop under test, and determining whether the loop is terminated by a short or open termination based on phase of the per-port calibrated echo signal.
    Type: Application
    Filed: March 7, 2008
    Publication date: November 13, 2008
    Applicant: CONEXANT SYSTEMS, INC.
    Inventors: Patrick Duvaut, Amitkumar Mahadevan, Vaibhav Dinesh
  • Publication number: 20080260012
    Abstract: An apparatus, including a detection unit configured to perform a non-linear detection on a receive signal, a first estimator configured to estimate a first quality measure based on the receive signal, and a second estimator configured to estimate a second quality measure dependent on the first quality measure and a performance measure of the detection unit is provided.
    Type: Application
    Filed: June 27, 2007
    Publication date: October 23, 2008
    Inventors: Kari Majonen, Markku J. Heikkila
  • Publication number: 20080247446
    Abstract: An apparatus includes a transmitter configured to transmit symbols to one or more receivers via a plurality of communication channels of a physical communication link. The transmitter is configured to estimate a phase of one or more off-diagonal elements of a channel matrix for the physical communication link based on values of signal-to-interference-plus-noise ratios at the one or more receivers.
    Type: Application
    Filed: August 31, 2007
    Publication date: October 9, 2008
    Inventors: Gerhard Guenter Theodor Kramer, Philip Alfred Whiting, Miroslav Zivkovic
  • Patent number: 7433395
    Abstract: A method, system and apparatus for reliable multicarrier communication in the presence of timing phase error is disclosed. Phase noise due to a sampling-time phase mismatch between a transmitter device and a receiver device is measured in a signal. A Gaussian noise power level in the signal is determined, and a gain factor associated with the phase noise is calculated. The gain factor is applied to the Gaussian noise power level to calculate an equivalent noise power. In one aspect, the equivalent noise power is used to determine a signal-to-noise ratio. In another aspect, the signal is a multicarrier signal including a plurality of sub-carriers.
    Type: Grant
    Filed: February 4, 2004
    Date of Patent: October 7, 2008
    Assignee: 2Wire, Inc.
    Inventor: Hossein Sedarat
  • Publication number: 20080240216
    Abstract: A method, where data is transmitted from a network node to user equipment in a succession of communication frames. An estimate indicative of the quality of the user equipment transmission channel in a reference communication frame is ascertained, and modified by an amount that varies in dependence on a configuration of the resources allocated to the user equipment in the reference communication frame. The modified estimate is used in selecting one or more connection parameters for a data transmission in a target communication frame.
    Type: Application
    Filed: May 31, 2007
    Publication date: October 2, 2008
    Inventors: Troels Kolding, Klaus Pedersen, Frank Frederiksen
  • Publication number: 20080240217
    Abstract: A device and method for estimating a carrier to interference-plus-noise ratio (CINR) in an OFDM system are provided. The CINR estimating method includes (a) receiving a preamble symbol and transmit subcarrier transmitted from a base station; (b) calculating an interference power and noise power using the preamble symbol and transmit subcarrier; (c) calculating a receive power used for the base station to transmit a preamble and data symbol; (d) estimating a preamble CINR value using an interference power, a noise power, and a receive power; (e) calculating the noise power from a subcarrier not transmitting a preamble; and (f) calculating an average CINR of data subcarriers using the preamble CINR value and the noise power.
    Type: Application
    Filed: August 18, 2006
    Publication date: October 2, 2008
    Applicants: SAMSUNG ELECTRONICS CO., LTD., KT CORPORATION, SK TELECOM CO., LTD., HANARO TELECOM, INC.
    Inventors: Yu-Ro Lee, Dong-Seung Kwon
  • Patent number: 7430237
    Abstract: In a UMTS (universal mobile telecommunications system) based system, a wireless receiver implements “effective signal-to-noise (Eb/No) based BER estimation.” In particular, the wireless receiver comprises a rake receiver, a processor and memory. The rake receiver processes a received signal and provides signal-to-noise ratio values for each slot of each received frame of the received signal. The processor converts these signal-to-noise ratio values for each received frame into an effective signal-to-noise ratio value for the received signal. The processor then uses the effective signal-to-noise ratio value as a pointer, or index, into a look-up table (stored in the memory) and retrieves a BER estimate therefrom.
    Type: Grant
    Filed: February 20, 2001
    Date of Patent: September 30, 2008
    Assignee: Lucent Technologies Inc.
    Inventors: Pantelis Monogioudis, Kiran M Rege
  • Publication number: 20080232444
    Abstract: Evaluation of the impact of impulse noise on a communication system can be utilized to determine how the system should be configured to adapt to impulse noise events. Moreover, the system allows for information regarding impulse noise events, such as length of the event, repetition period of the event and timing of the event, to be collected and forwarded to a destination. The adaptation can be performed during one or more of Showtime and initialization, and can be initiated and determined at either one or more of a transmitter and a receiver.
    Type: Application
    Filed: March 3, 2005
    Publication date: September 25, 2008
    Applicant: Aware, Inc.
    Inventor: Marcos C. Tzannes
  • Publication number: 20080225934
    Abstract: The present invention concerns a method for determining a corrected estimated variance representative of the condition of reception of signals representative of symbols transferred by an emitter to a receiver through a communication channel, wherein the method comprises the step, executed by the receiver, of producing an estimation of the variance by a Wiener channel estimator comprising a linear filter of which coefficients are determined at least from a given average signal to interference plus noise ratio value, the method being characterised in that it comprises farther step, executed by the receiver, of: multiplying the estimation of the variance by a correction factor, the value of the correcting factor being dependent at least on the number of coefficients of the linear filter of the Wiener channel estimator.
    Type: Application
    Filed: March 13, 2008
    Publication date: September 18, 2008
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Alain MOURAD, Damien Castelain
  • Publication number: 20080214118
    Abstract: In a communication medium including a first set A of n communication channels and a second set U of m communication channels, a method for selecting sensor channels in A for quantifying crosstalk from U, including operating A in a receive-only mode (FIG. 2 Step of Initialize Modem pool A. Work in receive-only mode.), choosing a subset S1 of A, estimating the expansion coefficients of A as a predefined function of subset S1 and signals received by A (FIG. 2 Step of Choose a set S1 of m modems in A and estimate the expansion coefficients gij of modems in A relative to S1), choosing a candidate subset S2 of size m of A where the determinant of a matrix of the expansion coefficients corresponding to the subset S2 is greater than that of the expansion coefficients corresponding to any other subset of size m of A divided by a predefined bound D (FIG. 2 Step of Choose an initial candidate subset S2 where det (AS2) det (AS)/D), calculating a threshold alpha, choosing a final subset S2 that is an -amplifier of (FIG.
    Type: Application
    Filed: March 23, 2005
    Publication date: September 4, 2008
    Applicant: ACTELIS NETWORKS (ISRAEL) LTD.
    Inventors: Ishai Ilani, Ram Zamir
  • Patent number: 7421009
    Abstract: A noise power estimation apparatus is disclosed. The noise power estimation apparatus includes: a part for calculating correlation between a received signal and a pilot signal so as to obtain a received power of the pilot signal for each path; a part for removing a multipath interference component from the received power of the pilot signal by using a predetermined power ratio between the pilot signal and a data signal so as to obtain a corrected received power of the pilot signal; a part for estimating an estimated total power of the pilot signal and the data signal included in the received signal based on the corrected received power and the predetermined power ratio; and a part for subtracting the estimated total power from a total power of the received signal so as to obtain a noise power.
    Type: Grant
    Filed: May 13, 2005
    Date of Patent: September 2, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Junichiro Kawamoto, Noriyuki Maeda, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 7418032
    Abstract: A method, circuit and system for altering the power consumption in communication links. A type of noise and an amount of jitter in a signal transmitted across a communication link is measured. Upon determining the contribution of the measured noise to the measured jitter in the signal, the measured noise is classified based on such contribution and the intensity of the measured jitter. The power consumption in a component(s) of the communication link may be adjusted based on the classification of the measured noise. For example, if the measured noise is classified as being a low amount of noise, then the power consumption of the component(s) may be reduced such as by lowering the voltage of the power supply and/or reducing the complexity of the circuitry. By reducing the power consumption when the communication link is not subject to the worst-case condition, a savings in power consumption may be made.
    Type: Grant
    Filed: March 15, 2005
    Date of Patent: August 26, 2008
    Assignee: International Business Machines Corporation
    Inventors: Juan Antonio Carballo, Hayden Clavie Cranford, Jr., Gareth John Nicholls, Vernon Roberts Norman, Brian Joel Schuh
  • Patent number: 7414581
    Abstract: A method for estimating signal/noise ratio is provided. The method comprises calculating a first signal/noise ratio (SNR) estimate using a technique with a first response time, calculating a second SNR estimate using a technique with a second, slower response time, and blending the first SNR estimate with the second SNR estimate.
    Type: Grant
    Filed: January 6, 2006
    Date of Patent: August 19, 2008
    Assignee: Honeywell International Inc.
    Inventor: Lawrence C. Vallot
  • Patent number: 7415063
    Abstract: A method for estimating uncorrelated noise in a distributed record of data including data samples that represent both signal and noise, provided that the signal is substantially in phase between adjacent data samples. The method begins with dividing the record of data into an even number of equal intervals. The method proceeds compiling a reduced data record by subtracting from every other data sample in the record of data one data sample that is adjacent to it. Finally, the method entails a step of estimating the noise power in the signal relative to the signal power by calculating the standard deviation as a measure of the magnitude of the noise.
    Type: Grant
    Filed: December 20, 2004
    Date of Patent: August 19, 2008
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Anthony A. Ruffa
  • Publication number: 20080187032
    Abstract: Embodiments provide a system and method for efficiently classifying different channel types in an orthogonal frequency division multiplexing (OFDM) system. Embodiments quantify the frequency selectivity in a channel by measuring the variation in a particular channel statistic across sub-carriers in an OFDM system, involve minimal complexity in implementation, and can be used in a variety of scenarios. One embodiment is a method for classifying channels in an OFDM system, comprising measuring variation of at least one channel statistic across sub-carriers, quantifying the variation to determine a measurement value, and applying the measurement value to at least one threshold to classify the channel.
    Type: Application
    Filed: January 31, 2008
    Publication date: August 7, 2008
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Tarkesh PANDE, Deric W. WATERS, Srinath HOSUR, Anuj BATRA
  • Publication number: 20080187031
    Abstract: An Orthogonal Frequency Division Multiple Access (OFDMA)-based mobile terminal and a method for measuring reception channel quality for use in the OFDMA-based mobile terminal are provided. A mobile terminal includes a transceiver for exchanging frequency signal with a base station and a control unit for calculating a Carrier-to-Interference and Noise Ratio (CINR) of a data subcarrier with a second preamble of a downlink frame received through the transceiver. A mobile terminal and a method for measuring a channel quality for the mobile terminal enable calculating a CINR of data subcarriers using information contained in a second preamble that is provided in a downlink frame proposed, whereby the mobile terminal can provide a base station with more reliable channel quality information, resulting in avoiding degradation of communication quality and improvement of system throughput.
    Type: Application
    Filed: December 28, 2007
    Publication date: August 7, 2008
    Applicant: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Seong Yun KO, Jun Hyuck Kim, Myeon Kee Youn, Seong Kyu Song
  • Publication number: 20080181290
    Abstract: A user equipment includes an estimator. The estimator is configured to select a first estimate of a signal-to-noise (SNR) ratio, calculate a first amplitude and first noise variance, calculate a second amplitude and a second noise variance, calculate a second SNR, calculate a resolution value, adjust the first SNR, and perform estimation iterations until the resolution value is equal to a predetermined value.
    Type: Application
    Filed: April 1, 2008
    Publication date: July 31, 2008
    Applicant: INTERDIGITAL TECHNOLOGY CORPORATION
    Inventors: Bin Li, Robert A. DiFazio, Ariela Zeira
  • Publication number: 20080181291
    Abstract: Methods and apparatuses identifying a co-channel interference signal in communications systems are disclosed. An exemplary method comprises generating an interference signal by subtracting a reconstructed desired signal from an at least partially demodulated composite signal, and generating synchronization statistics of interference signal using different scrambling codes. The interference signal is identified as the signal associated with the scrambling code that was used to generate an interference signal having a desired synchronization statistic.
    Type: Application
    Filed: April 4, 2008
    Publication date: July 31, 2008
    Applicant: THE DIRECTV GROUP, INC.
    Inventors: Guangcai Zhou, Ernest C. Chen, Joseph Santoru, Judith M. Wang
  • Publication number: 20080165839
    Abstract: Aspects of a method and system for dynamic adaptation and communicating differences in frequency-time dependent systems may include generating a time difference weighting factor and a frequency difference weighting factor, based on at least channel estimates. A time-frequency difference may be computed by forming a weighted sum comprising a time difference and a frequency difference, where forming the weighted sum uses at least the time difference weighting factor and the frequency weighting factor. A channel quality indicator (CQI) feedback message may be generated, comprising the time-frequency difference. The time difference weighting factor and/or the frequency difference weighting factor may be generated adaptively at a base station or a mobile terminal. The time difference and/or the frequency difference may be generated from estimated Signal-to-Noise-Ratios (SNRs) associated with the channel estimates. The SNRs may be based on at least the output of an MMSE receiver.
    Type: Application
    Filed: August 31, 2007
    Publication date: July 10, 2008
    Inventors: Uri Landau, Mark Kent, Vinko Erceg
  • Publication number: 20080165840
    Abstract: A satellite communications system adjusts a modulation and coding format for a downlink based on the slant range distance from the satellite to the receiving ground terminal. Modulation and coding formats are each associated with different sets of slant range distances. An estimated slant range from a satellite to a receiving ground terminal for a time period is determined, and the modulation and coding format associated with that slant range distance is identified. Data may then be transmitted by the satellite to the receiving ground terminal using the identified modulation and coding format for the time period. Additional factors may be considered in identifying the applicable modulation and coding format to be used.
    Type: Application
    Filed: January 8, 2008
    Publication date: July 10, 2008
    Applicant: ViaSat, Inc.
    Inventors: Rodney A. Morris, John R. Zlogar, Mark J. Vanderaar
  • Patent number: 7397871
    Abstract: The signal-to-noise ratio of a demodulated received signal is estimated by measuring the error vector magnitude (EVM) of the demodulated signal; and processing the measured EVM in combination with a correction term to estimate the signal-to-noise ratio of the demodulated signal. The correction term is a polynomial function of the measured EVM. The signal-to-noise ratio is estimated in accordance with the formula: E S N 0 ? 10 · LOG 10 ? ( ? · ? E S ? 4 ? [ ? ^ z + C ? ( ? ^ z ) ] 2 ) ? ? ( dB ) wherein {circumflex over (?)}z is the measured EVM based on the mean of a Rayleigh density of EVM measurements; and C is the correction term. For QPSK modulated signals, C is calculated in accordance with the formula: CQPSK({circumflex over (?)}z)?2.71×10?3{circumflex over (?)}z3?7.54×10?2{circumflex over (?)}z2+0.7{circumflex over (?)}z?2.25. For BPSK modulated signals, C is calculated in accordance with the formula: CBPSK({circumflex over (?)}z)?1.
    Type: Grant
    Filed: October 1, 2004
    Date of Patent: July 8, 2008
    Assignee: L-3 Communications Titan Corporation
    Inventors: John Robert Wiss, Timothy Lyle Blalock
  • Publication number: 20080151982
    Abstract: Embodiments relate to a system for conducting hearing aid compatibility testing of a mobile communication device. The system comprises: a simulated hand for supporting the mobile communication device during the testing; a probe; and a processor. The processor is configured to cause the probe to be positioned in a sequence of positions in proximity to the mobile communication device relative to an audio output component of the mobile communication device during the testing and to determine a field strength of a field radiated by the mobile communication device at the sequence of positions based on an output of the probe at each position.
    Type: Application
    Filed: December 20, 2006
    Publication date: June 26, 2008
    Applicant: RESEARCH IN MOTION LIMITED
    Inventors: Yihong Qi, Ying Tong Man, Perry Jarmuszewski, Daoud S. Attayi, Paul Gerard Giles Cardinal
  • Publication number: 20080144708
    Abstract: An equalization circuit and an equalization method implemented thereby are provided. A received symbol is received to generate a equalizer output. In the equalization circuit, an equalizer performs equalization to the received symbol based on a SNR value of the equalizer output. A SNR estimator coupled to the output of equalizer receives the equalizer output to measure the SNR value. The equalizer equalizes the received symbol by the LMS algorithm in which coefficients are recursively updated by a step size, and the step size is adjusted based on the SNR value.
    Type: Application
    Filed: December 19, 2006
    Publication date: June 19, 2008
    Applicant: MEDIATEK INC.
    Inventors: Yih-Ming Tsuie, Chiao-Chih Chang, Wei-Ting Wang
  • Patent number: 7388919
    Abstract: A system that adapts wireless link parameters for a wireless communication link. A measure is determined of errors occurring in communication over a wireless link. In a case that the measure of errors corresponds to more errors than a first predetermined threshold, communication changes from a first set of wireless link parameters to a second set of wireless link parameters. The second set of wireless link parameters corresponds to higher error tolerance than the first set of wireless link parameters. In a case that the measure of errors corresponds to fewer errors than a second predetermined threshold, communication changes from the first set of wireless link parameters to a third set of wireless link parameters. The third set of wireless link parameters corresponds to lower error tolerance than the first set of wireless link parameters. Preferably, the measure of errors is determined by monitoring a number of NACK messages and a number of ACK messages that occur.
    Type: Grant
    Filed: September 20, 2005
    Date of Patent: June 17, 2008
    Assignee: Aperto Networks, Inc.
    Inventors: Subir Varma, Reza Majidi-Ahy, Joseph Hakim, Wendy Chiu Fai Wong
  • Patent number: 7386043
    Abstract: A method and apparatus for increasing the spectral efficiency of communications systems by employing portions of the spectrum, which portions might otherwise be reserved as all or part of guard bands and not utilized (i.e., effectively wasted), for communicating at reduced power levels between devices that are determined to experience relatively high performance (e.g., relatively little path loss, etc.). In a communication system having a first predefined maximum system transmission power level for in-band transmissions, a method is provided for determining that communication performance between a first communication device and a second communication device exceeds a performance threshold. Based on the determination, a first band-edge channel for communication between the first communication device and the second communication device (i.e., transmission from the first device to the second device and/or visa versa) is assigned.
    Type: Grant
    Filed: November 8, 2006
    Date of Patent: June 10, 2008
    Assignee: ArrayComm LLC
    Inventor: Marc Goldburg
  • Publication number: 20080130730
    Abstract: A scheme for determining which of a set of taps that can potentially be used to measure a channel impulse response should be used to estimate the channel impulse response.
    Type: Application
    Filed: September 9, 2005
    Publication date: June 5, 2008
    Applicant: TIPCOM LIMITED
    Inventors: James Chapman, Jason Taylor, Cyril Valadon
  • Publication number: 20080130731
    Abstract: Noise measurements are made within a fraction of a single symbol period of a longest orthogonal code symbol. A control processor identifies an unoccupied code having a spreading factor that is less than a longest spreading factor for the system. A despreader measures symbol energy based on the unoccupied code and a noise estimator generates noise estimations based on the measured symbol energies.
    Type: Application
    Filed: July 23, 2007
    Publication date: June 5, 2008
    Inventors: Da-shan Shiu, Durga P. Malladi, Srikrishna Bhashyam
  • Publication number: 20080123786
    Abstract: The present invention is directed to a method and system for detecting and compensating for signal impairments in modulated signals. Phase noise and gain noise based signal impairments can be detected as a function of the difference between the optimal position in the constellation grid (the center) and the actual position in the constellation grid of a received symbol. As symbols are received, they are compared to optimal positions and a measure of the phase noise and gain noise can be determined for each symbol. Over a period of time, the detector can compute an average measure of phase noise and gain noise. When the average measure of phase noise and/or gain noise reaches a predefined threshold, the detector can indicate a phase noise based and/or gain noise based signal impairment has been detected to the receiver. The receiver can adjust one or more receive parameters in order to improve reception.
    Type: Application
    Filed: November 29, 2007
    Publication date: May 29, 2008
    Inventors: Supat Wongwirawat, Mark Hryszko, Devan Namboodiri, Raul A. Casas
  • Publication number: 20080117961
    Abstract: Disclosed is an apparatus and method for adaptively allocating transmission power for beamforming combined with orthogonal space-time block codes (OSTBC) in a distributed wireless communication system, the apparatus comprising: a plurality of sub-arrays for beamforming, which are geographically distributed and each of which comprises a plurality of distributed antennas placed in random groups; and a central processing unit for identifying performances of subsets by applying a predetermined power allocation scheme according to subsets which can be obtained by combining the sub-arrays, by means of a Nakagami fading parameter and information about large-scale fading of each of the sub-arrays, fed back from a receiving party, for determining a subset having a best performance as an optimal subset according to the identified performances, and for performing power allocation based on the subset set as the optimal subset.
    Type: Application
    Filed: October 12, 2007
    Publication date: May 22, 2008
    Inventors: Shuangfeng Han, Seong-Taek Hwang, Hoon Kim, Sang-Ho Kim, Jae-Hun Cho, Jae-Hoon Lee, Ki-Uk Song
  • Patent number: 7376207
    Abstract: A receiver architecture for receiving an FSK signal having a predetermined number of modulation levels includes a selectivity filter (206) for selectively passing a wanted channel and rejecting unwanted channels. The selectivity filter has a filter bandwidth of about one-half the bandwidth of a pre-modulation filter in a transmitter sending the FSK signal. A discriminator (208) is coupled to the selectivity filter for demodulating the signal. A symbol recovery processor (210) is coupled to the discriminator for recovering the symbols through a maximum likelihood sequence estimation (MLSE) technique utilizing N states for each symbol time, wherein N equals the predetermined number of modulation levels, and wherein templates used in the MLSE for symbol transitions are optimized with a bandwidth substantially less than the bandwidth of the pre-modulation filter.
    Type: Grant
    Filed: February 27, 2001
    Date of Patent: May 20, 2008
    Assignee: Freescale Semiconductor, Inc.
    Inventor: Weizhong Chen
  • Patent number: 7376178
    Abstract: An apparatus and method for estimation of signal-to-noise ratio (SNR) with low bias that is effective for both positive SNRs and small to negative SNRs. The estimation is based on an iterative solution for the maximum likelihood estimate of the amplitude from which the SNR can be computed. The estimation is applicable for various modulated systems, including BPSK, QPSK and MPSK.
    Type: Grant
    Filed: June 14, 2004
    Date of Patent: May 20, 2008
    Assignee: Interdigital Technology Corporation
    Inventors: Bin Li, Robert A. DiFazio, Ariela Zeira
  • Publication number: 20080112477
    Abstract: An apparatus and method for compensating a received signal level transmitted from a mobile terminal to a network through a measurement report message are provided. A received signal level compensation method for a mobile station includes measuring a received signal level of a multiframe; detecting an error of the received signal level; compensating, if an error of the received signal level is detected, the received signal level; and transmitting the compensated received signal level to the network.
    Type: Application
    Filed: September 10, 2007
    Publication date: May 15, 2008
    Inventors: Yun Seo Choi, Jung Ran Lee