Patents Examined by Mohammad H. Ghayour
  • Patent number: 7991040
    Abstract: Methods and apparatus for reduction of a peak to average ratio for an OFDM transmit signal. In an aspect, a method is provided for reducing a peak to average ratio of a transmit waveform. The method includes obtaining a primary scrambler sequence, generating a secondary scrambler sequence having a length characteristic based on data to be scrambled, and combining the primary and secondary scrambler sequences to produce a PAR reduction sequence. In another aspect, an apparatus is provided for reducing a peak to average ratio of a transmit waveform. The apparatus includes a secondary generator configured to generate a secondary scrambler sequence having a length characteristic based on data to be scrambled, and combining logic configured to combine a primary scrambler sequence and the secondary scrambler sequences to produce a PAR reduction sequence.
    Type: Grant
    Filed: September 11, 2006
    Date of Patent: August 2, 2011
    Assignee: QUALCOMM Incorporated
    Inventors: Durk L. van Veen, Fuyun Ling, Raghuraman Krishnamoorthi
  • Patent number: 7933357
    Abstract: An apparatus and method for transmission and reception in a multi-user Multiple-Input Multiple-Output (MIMO) communication system are provided. In a transmitter, a filter portion receives quantized Channel State Information (CSI) and Channel Quality Information (CQI) from a receiver, calculates a transmit filter value using on the quantized CSI and the CQI, determines an appropriate AMC level for the receiver, and sends a pilot signal including the transmit filter value and information about the determined AMC level on subcarriers in one of a preamble and data symbols. An antenna is used to send the output of the filter portion and receives data from the receiver.
    Type: Grant
    Filed: February 21, 2007
    Date of Patent: April 26, 2011
    Assignee: Samsung Electronics Co., Ltd
    Inventors: David Mazzarese, Sung-Ryul Yun, Dong-Seek Park
  • Patent number: 7933366
    Abstract: A channel estimation method and system using linear correlation based interference cancellation combined with decision-feedback-equalization (LCIC-DFE) are provided. The channel estimation method includes generating a first correlation sequence by calculating a linear correlation between a baseband sampled complex signal and a locally stored pseudo-noise signal and obtaining a second correlation sequence by iteratively removing inter-path interference from the first correlation sequence and generating a first channel impulse response (CIR) sequence based on the second correlation sequence. And, obtaining a third correlation sequence by removing random-data interference from the second correlation sequence based on the first CIR sequence and a feedback signal and generating a second CIR sequence based on the third correlation sequence.
    Type: Grant
    Filed: May 4, 2007
    Date of Patent: April 26, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Guanghui Liu
  • Patent number: 7924907
    Abstract: there is provided a spreading apparatus using a child orthogonal variable spreading factor (OVSF) code pair, including: a channel condition information receiving unit for receiving channel condition information including a channel condition metric; a switch controlling unit for receiving the channel condition information from the channel condition information receiving unit and transferring data stream according to the received channel station information; a first spreading unit for receiving the data stream from the switching controlling unit, and spreading the data stream using a single OVSF code; and a second spreading unit for receiving the data stream from the switching controlling unit, and spreading the data stream using a child OVSF code pair.
    Type: Grant
    Filed: August 16, 2007
    Date of Patent: April 12, 2011
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Sung-Rae Cho, Seong-Su Park, Hoo-Sung Lee, Byung-Jo Kim
  • Patent number: 7924912
    Abstract: A method and apparatus for advantageously utilizing the reset state of an RTZ shift register to guarantee proper data alignment at the feedback taps to facilitate decision feedback equalization (DFE) in a unified signaling system. An input data stream is sliced into an even data stream and an odd data stream, whereby the sliced data is compared to a programmable threshold depending upon a detection mode. Each bit of the even data stream is propagated through RTZ latches and each bit of the odd data stream is propagated through RTZ latches. At any given instant in time, a correct portion of the RTZ latch outputs contain zero information, so that each latch output may be summed in a current mode without the need for any intervening logic. The input data stream is summed in current mode with the feedback data and converted to voltage prior to sampling the currently received data bit.
    Type: Grant
    Filed: November 1, 2006
    Date of Patent: April 12, 2011
    Assignee: Xilinx, Inc.
    Inventors: Shahriar Rokhsaz, Michael A. Nix
  • Patent number: 7924925
    Abstract: A video encoder including a processing block and an external memory storing a current frame and a reference frame. The processing block includes a memory interface, a local memory and a processor. The processor encodes the current frame in raster scan macroblock order for FMO using information from the reference frame, converts encoded information into compressed information, and organizes the compressed information according to a predetermined FMO. The processor organizes the compressed information according to any suitable FMO organization such as scattered, interleaved, etc. The processor stores the compressed information into multiple slice groups into the local memory or into the external memory, where the slice groups are organized according to the FMO. The processor loads a search window macroblock into the local memory if not already stored in the local memory. The processor may generate unfiltered reconstructed information and store the unfiltered reconstructed information into the local memory.
    Type: Grant
    Filed: February 24, 2006
    Date of Patent: April 12, 2011
    Assignee: Freescale Semiconductor, Inc.
    Inventor: Zhongli He
  • Patent number: 7916785
    Abstract: This invention provides a coding method and apparatus capable of increasing the coding efficiency. According to this invention, an image processing apparatus which performs predictive coding using image data of a different frame as a reference picture includes a prediction unit which performs motion compensated prediction for each reference picture in at least one reference list formed from a set of reference pictures for prediction, a reference list update unit which updates the reference list by adding or deleting the reference picture, a reference counter unit which measures, for each reference picture, a count at which the reference picture is used for motion compensation predictive coding, and an update picture determination unit which determines a reference picture to be updated in the reference list by using the measurement result of the reference counter unit.
    Type: Grant
    Filed: February 1, 2006
    Date of Patent: March 29, 2011
    Assignee: Canon Kabushiki Kaisha
    Inventor: Jun Makino
  • Patent number: 7916797
    Abstract: An error tracking apparatus and method for tracking a residual frequency error, a phase error, a timing error, and a signal amplitude variation to enhance a phase error tracking performance and a tracking speed in an orthogonal frequency division multiplexing (OFDM) system is provided.
    Type: Grant
    Filed: November 22, 2005
    Date of Patent: March 29, 2011
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Heejung Yu, Taehyun Jeon, Myung-Soon Kim, Eun-Young Choi, Sok-Kyu Lee, Deuk-Su Lyu
  • Patent number: 7912165
    Abstract: A method is disclosed, including identifying a preamble in a frame, where the preamble has a preamble length 1. M data items received in succession are stored. The m data items once divided into n portions, where the data items in each portion have respectively been received at successive times and where m and n are natural numbers and the following applies to m and n: m>n, m>1, n>1. The n portions are respectively correlated to the expected values to form component correlation results. Delaying the component correlation results, with at least two component correlation results being delayed by different lengths. The method also includes combining the delayed component correlation results to form a total correlation value. The total correlation value is used to determine whether the m received data items contain the preamble of a frame.
    Type: Grant
    Filed: May 25, 2007
    Date of Patent: March 22, 2011
    Assignee: Infineon Technologies AG
    Inventors: Stefan Herzinger, Andreas Menkhoff, Stefan Meier, Norbert Neurohr
  • Patent number: 7907678
    Abstract: In a distortion generation path of a power series predistorter, a frequency characteristic compensator that adjusts the frequency characteristic of a distortion component is provided in series with an odd-order distortion generator. The output of a power amplifier is divided to obtain an output signal of the power amplifier, the output signal of the power amplifier is down-converted by a down converter, and a distortion detector detects a distortion component in the down-converted signal of base band. The frequency characteristic of the distortion component is split into windows each having a band width of ?f by a distortion component frequency characteristic splitter, and the power of the distortion component in each window is detected. Based on the detected power, the frequency characteristic compensator adjusts a part of the frequency characteristic of the distortion component associated with each window.
    Type: Grant
    Filed: May 16, 2006
    Date of Patent: March 15, 2011
    Assignee: NTT DoCoMo, Inc.
    Inventors: Shinji Mizuta, Yasunori Suzuki, Shoichi Narahashi
  • Patent number: 7907664
    Abstract: Systems and method to compress digital video based on human factors expressed as a desirability score are provided. A particular method includes passing a digital input signal through a pulse-width modulator and passing an output of the pulse-width modulator through a power switching device. An output of the power switching device has a plurality of pulses. The method includes receiving the output of the power switching device at a first input of a comparator and receiving a reference voltage at a second input of the comparator. The method includes determining a net signal based on an output of the comparator and determining a timing error signal based on the net signal and the digital input signal. The method also includes adjusting the digital input signal to compensate for harmonic distortion based at least in part on the timing error signal.
    Type: Grant
    Filed: December 7, 2009
    Date of Patent: March 15, 2011
    Assignee: Sigmatel, Inc.
    Inventors: Zukui Song, Michael Determan
  • Patent number: 7907672
    Abstract: The invention is related to a synchronization method in a communication system. The invention includes: carrying out a coarse time offset and frequency offset estimation, first estimating errors in the coarse time-offset and frequency offset estimation by using a maximum-likelihood time-offset estimation and joint optimisation of time-offset and frequency-offset, second estimating frequency offset and time offset by using error estimates in a closed tracking loop.
    Type: Grant
    Filed: September 25, 2006
    Date of Patent: March 15, 2011
    Assignee: Nokia Corporation
    Inventor: Gilles Charbit
  • Patent number: 7903717
    Abstract: When a receiver (200) receives a signal transmitted from a transmitter, an A/D converter (204) converts the signal into a digital signal having two or more levels by A/D conversion. A zero-level detector (207) converts the signal into a two-level digital signal of positive and negative levels. The converted signals are subjected to spectrum despreading by correlators (206, 208), respectively. Whichever signal has a higher intensity is selected by absolute value detectors (209, 210), a comparator (211), and a switch (212). A decoder (213) decodes the selected signal. In a receiving state where the zero-level detector (207) is selected, the transmitter transmits the transmission signal after the signal is converted into a two-level signal. In a receiving state where the A/D converter (204) is selected, the transmitter transmits the transmission signal after the signal is converted into a signal having two or more levels.
    Type: Grant
    Filed: March 2, 2005
    Date of Patent: March 8, 2011
    Assignee: National Institute of Information and Communications Technology, Incorporated Administrative Agency
    Inventors: Satoshi Takahashi, Hiroshi Harada, Chang-Jun Ahn
  • Patent number: 7903772
    Abstract: A demodulator for use in a receiver converts a digital baseband signal into inbound digital symbols with reduced hardware complexity and reduced power consumption. The demodulator includes a lowpass filter operably coupled to filter the digital baseband signal to produce a filtered digital baseband signal, and an equalizer operating at a first sampling rate to equalize the frequency response of the digital baseband signal such that the receiver overall in-band frequency response approximates the frequency response of a square root raised cosine filter to produce an adjusted digital baseband signal. An interpolator receives the adjusted digital baseband signal at the first sampling rate and interpolates the adjusted digital baseband signal to produce an interpolated digital baseband signal at a second sampling rate, from which the inbound digital symbols can be generated.
    Type: Grant
    Filed: February 4, 2005
    Date of Patent: March 8, 2011
    Assignee: Broadcom Corporation
    Inventor: Henrik T. Jensen
  • Patent number: 7903774
    Abstract: According to a method for generating a system time clock in a receiving device for digital packetized elementary data streams (E), the packetized elementary data streams (E) being generated in a transmitting device by sampling at a sampling frequency (fsample) synchronized by a system time clock of the transmitting device, the sampling frequency (fsample) of one data stream is determined in the receiving device, and the program clock reference counter is synchronized with the data stream's sampling frequency.
    Type: Grant
    Filed: May 30, 2003
    Date of Patent: March 8, 2011
    Assignee: Robert Bosch GmbH
    Inventors: Joerg Barthel, Christian Mittendorf
  • Patent number: 7903761
    Abstract: The present invention provides a method and apparatus for correcting direct current (DC) offsets in radio output signals. The invention comprises a radio processor and a baseband processor. During a calibration routine, the baseband processor measures DC offset produced by the radio processor, generates a corresponding DC offset correction value, and writes the correction value to a discrete memory in the radio processor via a serial processor interface. During a subsequent normal receive operation, the radio processor reads the DC offset correction value from memory and feeds it into a into a digital to analog converter to produce an analog signal that in turn is fed into a radio receive path to nullify undesired DC offset.
    Type: Grant
    Filed: March 31, 2006
    Date of Patent: March 8, 2011
    Assignee: QUALCOMM Incorporated
    Inventor: Brian C. Joseph
  • Patent number: 7899109
    Abstract: An m-code GPS receiver receives m-code GPS communication signals having a multimodal autocorrelation, using an m-code mode identifier unambiguously determining a mode value of one of the m-code modal peaks coherently aligned to a coherent unimodal detected envelope, based on sequential probability estimation in an m-code envelope tracking filter using filter residual estimation or with a coherent m-code and c/a-code tracking filter also based on filter residual estimation, for generating m-code phase errors, for unambiguous and precise m-code code phase tracking in closed feedback loops, for preferred use in navigation systems.
    Type: Grant
    Filed: August 8, 2006
    Date of Patent: March 1, 2011
    Assignee: The Aerospace Corporation
    Inventor: Randal K. Douglas
  • Patent number: 7894558
    Abstract: A receiver circuit controls a power source of a front-end circuit and a demodulator using a first power source control signal. Upon receiving data of a plurality of receiving slots having a guard bit provided between receiving slots adjacent to each other, the first power source control signal becomes a power source ON signal before starting receiving of the data, then becomes a power source OFF signal within the guard bit, and becomes a power source OFF signal after completing the receiving of the data. The receiver circuit controls a power source of an active filter circuit using a second power source control signal, which becomes a power source OFF signal after completing the receiving of the data after becoming a power source ON signal before starting the receiving of the data.
    Type: Grant
    Filed: November 3, 2006
    Date of Patent: February 22, 2011
    Assignee: Panasonic Corporation
    Inventors: Mamoru Nishimura, Koji Takahashi, Satoshi Yamaguchi, Tetsurou Yokota
  • Patent number: 7889822
    Abstract: A Radio Frequency (RF) receiver includes a RF front end and a baseband processing module coupled to the RF front end that is operable to receive a time domain signal that includes desired signal and interfering signal time domain training symbols and time domain data symbols.
    Type: Grant
    Filed: September 21, 2006
    Date of Patent: February 15, 2011
    Assignee: Broadcom Corporation
    Inventors: Junqiang Li, Nelson R. Sollenberger, Joseph Boccuzzi, Li Fung Chang
  • Patent number: 7889781
    Abstract: A system for processing radio frequency (RF) signals includes a searcher and a Cluster Path Processor (CPP). The searcher detects a maximum signal energy level and position of at least one of a plurality of individual distinct path signals in a signal cluster, wherein at least a portion of the plurality of individual distinct path signals is received within a duration of a corresponding delay spread. The CPP includes a group finger array having a plurality of group fingers and determines a coarse sampling position of the group finger array based upon the position of the at least one of a plurality of individual distinct path signals in the signal cluster. The CPP determines a fine sampling position based upon determines a composite channel energy estimate for the plurality of individual distinct path signals. Using this fine sampling position, the CPP receives at least a portion of the plurality of individual distinct path signals by the group finger array.
    Type: Grant
    Filed: September 21, 2006
    Date of Patent: February 15, 2011
    Assignee: Broadcom Corporation
    Inventors: Junqiang Li, Mark David Hahm, Li Fung Chang