Patents by Inventor Songping Wu

Songping Wu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20120201276
    Abstract: In a wireless communication system in which communication devices exchange information utilizing data units that conform to a first format, wherein the first format includes a short training field (STF) spread with a first spread code, a method for generating a physical layer (PHY) data unit that conforms to a second format includes generating a first portion of the PHY data unit to indicate the PHY data unit conforms to the second format. The first portion of the PHY data unit includes an STF spread with a second spread code different than the first spread code. The method also includes generating a second portion of the PHY data unit according to the second format. The second portion of the PHY data unit includes PHY information elements not specified by the first format.
    Type: Application
    Filed: April 17, 2012
    Publication date: August 9, 2012
    Inventors: Hongyuan Zhang, Songping Wu, Hui-Ling Lou, Rohit U. Nabar
  • Patent number: 8195112
    Abstract: Time-reversal filtering may be used to temporally focus a signal to be transmitted. Power can be reduced at the transmitter so that the temporally focused signal is within spectral mask requirements. In one embodiment, the effect of the time-reversal filter on the power spectral density for a particular transmitted signal can be calculated and the predicted power spectral density can be compared to the permitted spectral mask to identify violations, if any, of the spectral mask. The transmitter power can then be reduced by the amount of the violation. In another embodiment, a set of different time-reversal filters that meet the spectral mask requirements can be provided in advance, and the most appropriate filter—e.g., the one with the best signal-to-noise ratio for the particular signal—can be chosen from the set of filters.
    Type: Grant
    Filed: June 10, 2009
    Date of Patent: June 5, 2012
    Assignee: Marvell International Ltd.
    Inventors: Hongyuan Zhang, Arul Durai Murugan Palanivelu, Rohit U. Nabar, Songping Wu, Hui-Ling Lou
  • Patent number: 8184052
    Abstract: A method for beamforming in a communication system includes receiving a plurality of signals via a plurality of antennas, where the plurality of signals corresponds to at least one known training signal, generating a respective one of a plurality of different antenna weight vectors to be applied to the plurality of antennas as each of the plurality of signals is received, where each of the plurality of antenna weight vectors is a respective base vector of a unitary matrix, and generating a receiver antenna weight vector based on at least the received plurality of signals, the plurality of different antenna weight vectors, and the at least one known training signal.
    Type: Grant
    Filed: September 18, 2009
    Date of Patent: May 22, 2012
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Manyuan Shen, Quan Zhou, Hongyuan Zhang, Hui-Ling Lou
  • Patent number: 8175118
    Abstract: A method of generating a data unit preamble includes generating a first field associated with at least one of packet synchronization information or frame boundary indication, and generating a second field associated with channel estimation, including generating a first channel estimation sequence (CES) symbol and generating a second CES symbol, so that at least one of 1) a sequence in the first field serves as a cyclic prefix of the first CES symbol, 2) a beginning portion of the second CES symbol serves as a cyclic postfix of the first CES symbol, or 3) an ending portion of the first CES symbol serves as a cyclic prefix of the second CES symbol.
    Type: Grant
    Filed: May 15, 2009
    Date of Patent: May 8, 2012
    Assignee: Marvell World Trade Ltd.
    Inventors: Hongyuan Zhang, Rohit U. Nabar, Songping Wu, Hui-Ling Lou, Quan Zhou
  • Patent number: 8175119
    Abstract: A method for generating a preamble of a data unit includes generating a short training field (STF) of the preamble to include one of a repeating series of a sequences or a repeating series of b sequences, such that a and b are complementary sequences, a sum of out-of-phase aperiodic autocorrelation coefficients of a and b is zero, and where the STF is associated with at least synchronization information, and generating a long training field (LTF) of the preamble after the STF to include a? sequences and b? sequences, such that a? is the sequence a cyclically shifted by zero or more positions, b? is the sequence b cyclically shifted by zero or more positions, and where the LTF is associated with channel estimation information.
    Type: Grant
    Filed: May 15, 2009
    Date of Patent: May 8, 2012
    Assignee: Marvell World Trade Ltd.
    Inventors: Hongyuan Zhang, Rohit U. Nabar, Songping Wu, Hui-Ling Lou
  • Patent number: 8165185
    Abstract: In a wireless communication system wherein communication devices exchange information utilizing data units that conform to a first format, wherein the first format includes a short training field (STF) spread with a first spread code and a first cover code, a method is for generating a physical layer (PHY) data unit that conforms to a second format, wherein the PHY data unit is for transmitting PHY information. A first portion of the PHY data unit is generated to indicate the PHY data unit conforms to the second format, wherein the first portion of the PHY data unit includes an STF spread with at least one of a second spread code different than the first spread code or a second cover code different than the first cover code. A second portion of the PHY data unit is generated according to the second format, wherein the second portion of the PHY data unit includes PHY information elements not specified by the first format.
    Type: Grant
    Filed: September 29, 2009
    Date of Patent: April 24, 2012
    Assignee: Marvell World Trade Ltd.
    Inventors: Hongyuan Zhang, Songping Wu, Hui-Ling Lou, Rohit U. Nabar
  • Patent number: 8139688
    Abstract: A differential receiver which provides for estimation and tracking of frequency offset, together with compensation for the frequency offset. Estimation and tracking of the frequency offset is undertaken in the phase domain, which reduces computational complexity and allows frequency offset estimation and tracking to be accomplished by sharing already-existing components in the receiver. Compensation for the frequency offset can be performed either in the time domain, before differential detection, or in the phase domain, after demodulation, or can be made programmably selectable, for flexibility.
    Type: Grant
    Filed: September 29, 2010
    Date of Patent: March 20, 2012
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Hui-Ling Lou
  • Patent number: 8050643
    Abstract: In a method and system for controlling gain in an RF receiver, an RF signal is analyzed over different attack and decay windows, from which the receiver determines (1) if the signal is in an attack condition with dip values below a threshold level thus indicating a need for increasing signal gain, or (2) if the signal is in a decay condition with threshold values above a threshold level thus indicating a need for decreasing signal gain. The receiver applies attack and decay windows of different sizes and in an asynchronous manner to create a gain control scheme that is insensitive to transient effects such as channel interference and deep fading that affect the intensities of an in-band signal.
    Type: Grant
    Filed: May 9, 2008
    Date of Patent: November 1, 2011
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Hua Qian, Gang Liu, King Chun Tsai, Lawrence Tse, Hui-Ling Lou
  • Patent number: 7995666
    Abstract: In a method for synchronizing a receiver to a synchronous signal, in a signal having been processed based on an automatic gain control (AGC) with a varying gain, a symbol is detected. An estimated beginning of a subsequent frame is determined based on the detected symbol. A gain of the AGC is fixed for a period during which the estimated start of the subsequent frame is processed by the AGC. A transform of the signal is analyzed to determine if the estimated start of the subsequent frame corresponds to an actual start of the subsequent frame. If the estimated start of the subsequent frame does not corresponds to the actual start of the subsequent frame, the gain of the AGC is allowed to resume varying and, a further symbol in the signal is detected, the signal having been processed based on the varying gain of the AGC.
    Type: Grant
    Filed: October 7, 2010
    Date of Patent: August 9, 2011
    Assignee: Marvell International Ltd.
    Inventors: Qing Zhao, Jungwon Lee, Leilei Song, Songping Wu, Hui-Ling Lou
  • Patent number: 7983233
    Abstract: Orthogonal frequency division multiplexing (OFDM) has been specified by IEEE 802.11a standard as the transmission technique for high-rate wireless local area networks (WLANs). Performance of an OFDM system, however, is heavily degraded by random Wiener phase noise, which causes both common phase error (CPE) and inter-carrier interference (ICI). A method and algorithm is disclosed for efficiently eliminating the effect of phase noise in OFDM based WLANs.
    Type: Grant
    Filed: October 22, 2007
    Date of Patent: July 19, 2011
    Assignee: New Jersey Institute of Technology
    Inventors: Yeheskel Bar-Ness, Songping Wu
  • Patent number: 7978106
    Abstract: A receiver including an automatic gain control module, a digital signal processor module, and a control module. The automatic gain control module has a gain that varies from a nominal value in response to the receiver receiving an input signal. The automatic gain control module is configured to generate a first signal in response to the gain settling at a value different from the nominal value. In response to the input signal not being an interference signal, the digital signal processor module is configured to process the input signal and generate a second signal. Subsequent to the first signal being generated and prior to the second signal being generated, the control module is configured to determine whether the input signal is an interference signal based on whether the second signal is generated within a predetermined time period subsequent to the first signal being generated.
    Type: Grant
    Filed: January 3, 2011
    Date of Patent: July 12, 2011
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Yui Lin, Hui-Ling Lou
  • Patent number: 7974367
    Abstract: The present invention provides for receiving a radio frequency signal which encodes transmitted data, and for outputting data corresponding to the transmitted data. The radio frequency signal is received and converted to inphase and quadrature data. Phase information is extracted from the inphase and quadrature data. A symbol timing for the radio signal is determined based on the extracted phase information. The transmitted data encoded within the radio frequency signal is detected and processed based on the determined symbol timing. Data is output based on the detected and processed transmitted data. Since symbol timing is determined based on phase information, in the phase domain, a radio frequency receiver can be constructed with a lower complexity and a simpler structure.
    Type: Grant
    Filed: March 15, 2010
    Date of Patent: July 5, 2011
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Hui-Ling Lou
  • Patent number: 7944984
    Abstract: An I/Q calibration system for a quadrature amplitude modulation (QAM) mode transceiver includes a signal generator that generates reference in-phase (I) and quadrature (Q) signals. An I/Q mismatch compensation module generates compensated I and Q signals based on the reference I and Q signals and amplitude and phase correction signals. An I/Q mismatch calibration module generates the amplitude and phase correction signals. A phase stepper module varies a phase of the reference I and Q signals based on the amplitude and phase correction signals.
    Type: Grant
    Filed: February 12, 2007
    Date of Patent: May 17, 2011
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Qing Zhao, Atul Salhotra, Hui-Ling Lou, Thomas B. Cho
  • Patent number: 7864091
    Abstract: A system comprises a gain control module that selectively generates a gain locked signal based on a wireless input signal. A sync detect module that selectively generates a sync detect signal based on the wireless input signal. An interference detection module that selectively generates a wireless interference detection signal based on the gain locked signal and the sync detect signal.
    Type: Grant
    Filed: June 9, 2008
    Date of Patent: January 4, 2011
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Yui Lin, Hui-Ling Lou
  • Patent number: 7855666
    Abstract: A calibration module includes an absolute value module that generates first and second magnitude signals based on a first signal and a second signal, respectively. A first module generates an amplitude correction signal for a quadrature-amplitude modulated (QAM) signal based on the first and second magnitude signals. A second module generates a phase correction signal for the QAM signal based on the first signal and the second signal.
    Type: Grant
    Filed: May 20, 2008
    Date of Patent: December 21, 2010
    Assignee: Marvell International Ltd.
    Inventors: Rahul Kopikare, Songping Wu, Poh Boon Leong, Thomas Cho, Yui Lin
  • Publication number: 20100264902
    Abstract: A system includes a sampling module, a counter module, and a frequency characteristic module. The sampling module samples radio frequency (RF) signals on a first channel for a first predetermined period and a second predetermined period that is subsequent to the first predetermined period. The counter module increments first and second counts when the samples collected during the first and second predetermined periods reverse polarity, respectively. The frequency characteristic module determines a frequency of the RF signal based on at least one of the first and the second counts and determines frequency variation of the RF signal based on the first and second counts.
    Type: Application
    Filed: June 29, 2010
    Publication date: October 21, 2010
    Inventors: Bhaskar V. Nallapureddy, Songping Wu, Tsunglun Yu, Hui-Ling Lou
  • Patent number: 7813436
    Abstract: In a method for synchronizing a receiver to a synchronous signal, a plurality of potential symbols are detected in a signal, the signal having been processed based on automatic gain control (AGC) with a varying gain. Next frame potential symbols corresponding to potential symbols in the plurality of potential symbols are determined, the next frame potential symbols being in frames subsequent to the frames in which the corresponding potential symbols are located. A gain of the AGC is fixed for each corresponding symbol interval during which a next frame potential symbol is operated on by the AGC. In between next frame potential symbols, the AGC is allowed to vary. Next frame potential symbols are analyzed after a transform is calculated to determine if any correspond to a start of a frame.
    Type: Grant
    Filed: September 6, 2007
    Date of Patent: October 12, 2010
    Assignee: Marvell International Ltd.
    Inventors: Qing Zhao, Jungwon Lee, Leilei Song, Songping Wu, Hui-Ling Lou
  • Patent number: 7809083
    Abstract: A differential receiver which provides for estimation and tracking of frequency offset, together with compensation for the frequency offset. Estimation and tracking of the frequency offset is undertaken in the phase domain, which reduces computational complexity and allows frequency offset estimation and tracking to be accomplished by sharing already-existing components in the receiver. Compensation for the frequency offset can be performed either in the time domain, before differential detection, or in the phase domain, after demodulation, or can be made programmably selectable, for flexibility.
    Type: Grant
    Filed: August 8, 2006
    Date of Patent: October 5, 2010
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Hui-Ling Lou
  • Patent number: 7773014
    Abstract: A receiver module includes an automatic gain control module having a gain that varies from a nominal value in response to the receiver module receiving an input signal. The automatic gain control module is configured to generate a first signal in response to the gain settling at a value different from the nominal value. A peak detector module is configured to generate a second signal in response to the gain deviating from the nominal value by a predetermined amount. The peak detector module generates the second signal prior to the automatic gain control module generating the first signal. A control module is configured to receive each of the first signal and the second signal and reset the receiver module to halt processing of the input signal in response to the control module not receiving the first signal within a predetermined amount of time subsequent to the control module receiving the second signal.
    Type: Grant
    Filed: November 23, 2009
    Date of Patent: August 10, 2010
    Assignee: Marvell International Ltd.
    Inventors: Songping Wu, Yui Lin, Hui-Ling Lou
  • Patent number: 7747222
    Abstract: A system includes a sampling module, a counter module, and a frequency characteristic module. The sampling module samples radio frequency (RF) signals on a first channel for a first predetermined period and a second predetermined period that is subsequent to the first predetermined period. The counter module increments first and second counts when the samples collected during the first and second predetermined periods reverse polarity, respectively. The frequency characteristic module determines a frequency of the RF signal based on at least one of the first and the second counts and determines frequency variation of the RF signal based on the first and second counts.
    Type: Grant
    Filed: July 26, 2006
    Date of Patent: June 29, 2010
    Assignee: Marvell World Trade Ltd.
    Inventors: Bhaskar V. Nallapureddy, Songping Wu, Tsunglun Yu, Hui-Ling Lou