Patents by Inventor Li Wenzhen

Li Wenzhen 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).

  • Patent number: 7769095
    Abstract: An apparatus for timing recovery in an OFDM system comprises a third order phase lock loop comprising a Fast Fourier Transform stage for receiving a number of input signals in the time domain and transforming the signals to the frequency domain. A phase rotation stage adjusts the phase of one or more of the transformed signals. A frequency offset estimation stage estimates frequency offset between sampled signals and a first accumulator accumulates the frequency offset estimates. A low pass filter couplable to an output of the first accumulator stabilizes the phase lock loop. A second accumulator accumulates outputs of the low pass filter and controls phase rotation in the phase rotation stage. A controller controls timing associated with the window of operation of the Fast Fourier Transform process and is itself controlled by the second accumulator. There is also disclosed a receiver comprising the above apparatus and a method for timing recovery in an OFDM system.
    Type: Grant
    Filed: August 8, 2007
    Date of Patent: August 3, 2010
    Assignee: Oki Techno Centre (Singapore) Pte Ltd
    Inventors: Li Wenzhen, Tomisawa Masayuki
  • Publication number: 20080069252
    Abstract: An apparatus for timing recovery in an OFDM system comprises a third order phase lock loop comprising a Fast Fourier Transform stage for receiving a number of input signals in the time domain and transforming the signals to the frequency domain. A phase rotation stage adjusts the phase of one or more of the transformed signals. A frequency offset estimation stage estimates frequency offset between sampled signals and a first accumulator accumulates the frequency offset estimates. A low pass filter couplable to an output of the first accumulator stabilizes the phase lock loop. A second accumulator accumulates outputs of the low pass filter and controls phase rotation in the phase rotation stage. A controller controls timing associated with the window of operation of the Fast Fourier Transform process and is itself controlled by the second accumulator. There is also disclosed a receiver comprising the above apparatus and a method for timing recovery in an OFDM system.
    Type: Application
    Filed: August 8, 2007
    Publication date: March 20, 2008
    Inventors: Li Wenzhen, Tomiswa Masayuki