Patents by Inventor Ying Chang Liang

Ying Chang Liang 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: 20100015935
    Abstract: An embodiment of the invention provides a method for classifying a received signal. The method includes determining a covariance matrix of signal values of the received signal, and determining an eigenvalue matrix of the covariance matrix. The eigenvalue matrix includes the eigenvalues of the covariance matrix. A first function is determined from at least one eigenvalue of the eigenvalues of the covariance matrix. A second function is determined from at least one eigenvalue of the eigenvalues of the covariance matrix, wherein the second function is different from the first function. Dependent from a comparison between a value of the first function and a value of the second function, the received signal is classified into a signal comprising data or into a noise signal.
    Type: Application
    Filed: July 5, 2007
    Publication date: January 21, 2010
    Inventors: Yonghong Zeng, Ying-Chang Liang
  • Publication number: 20090304045
    Abstract: A method for transmitting data between a communication network unit and a plurality of communication devices is provided, comprising using a plurality of carrier signals grouped into at least one carrier signal group, determining a subset of communication devices of the plurality of communication devices, and using the at least one carrier signal group for data transmission between the communication network and the communication devices of the subset of communication devices.
    Type: Application
    Filed: January 9, 2007
    Publication date: December 10, 2009
    Inventors: Zhongding Lei, Ying Chang Liang, Xiaoming Peng, Po Shin Francois Chin
  • Publication number: 20090252048
    Abstract: A method of determining available frequency ranges for at least one communication device is provided. The method comprises providing a downlink transmission time interval, determining available frequency ranges within a plurality of frequency ranges after the downlink transmission time interval, and providing an uplink transmission time interval after the determining of the available frequency ranges.
    Type: Application
    Filed: November 7, 2006
    Publication date: October 8, 2009
    Applicant: AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCH
    Inventors: Ying Chang Liang, Anh Tuan Hoang, Ashok Kumar Marath, Zhongding Lei, Po Shin Francois Chin
  • Publication number: 20090219858
    Abstract: A method for transmitting a signal to a communication device in a cellular communication system is provided. The method comprises transmitting a signal using a first antenna being provided in a first sector of the cellular communication system, and transmitting another signal using a second antenna being provided in a second sector of the cellular communication system, wherein the first sector at least partially overlaps the second sector, wherein the signal transmitted by the second antenna is a cyclic delayed version of the signal transmitted by the first antenna.
    Type: Application
    Filed: November 7, 2006
    Publication date: September 3, 2009
    Applicant: AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCH
    Inventors: Ying Chang Liang, Yan Wu, Sumei Sun, Woon Han Chin, Wing Seng Leon, Po Shin Francois Chin
  • Publication number: 20090219944
    Abstract: A method of allocating frequency ranges to at least one communication device is provided. The method comprises determining available frequency ranges within a plurality of frequency ranges, combining the available frequency ranges to at least one combined logical frequency range, and allocating the at least one combined logical frequency range to the at least one communication device.
    Type: Application
    Filed: November 3, 2006
    Publication date: September 3, 2009
    Inventors: Ying Chang Liang, Yonghong Zeng, Zhongding Lei, Po Shin Francois Chin
  • Publication number: 20090190570
    Abstract: A method of transmitting data from a first communication device to a second communication device is provided. The method comprises transmitting at least one first data portion, transmitting a second data portion synchronized with the transmission of a corresponding data portion of a third communication device to the second communication device, and the transmission of the at least one first data portion being arranged such that it is received by the second communication device before the data portion of the third communication device corresponding to the second data portion.
    Type: Application
    Filed: November 6, 2006
    Publication date: July 30, 2009
    Applicant: AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCH
    Inventors: Ashok Kumar Marath, Ying Chang Liang, Anh Tuan Hoang, Yonghong Zeng, Wing Seng Leon
  • Publication number: 20090086839
    Abstract: A method for decoding an input data sequence is provided. The method comprises generating a plurality of test sequences, determining an order for the plurality of test sequences, such that each test sequence differs from its adjacent test sequences by a respective predefined number of bits, and carrying out a maximum likelihood process with the ordered test sequences and the input data sequence thereby generating a maximum likelihood sequence.
    Type: Application
    Filed: November 7, 2006
    Publication date: April 2, 2009
    Applicant: Agency for Science, Technology and Research
    Inventors: Changlong Xu, Ying Chang Liang, Wing Seng Leon
  • Publication number: 20080187034
    Abstract: A method for equalizing a digital signal received via at least one communication channel is described, wherein a block of received signal values is processed by a block-iterative equalizer (200). The equalizer comprises a feedback unit (202) and a feed-forward unit (201) each corresponding to the multiplication by a respective matrix. The matrices are updated in the iterative process.
    Type: Application
    Filed: August 15, 2005
    Publication date: August 7, 2008
    Inventors: Ying Chang Liang, Sumei Sun, Chin Keong Ho
  • Publication number: 20080101499
    Abstract: A transmitter is described which has a determination unit for determining a plurality of symbols (301) such that each symbol (301) comprises a tail component (302) and the plurality is determined in such a way that the tail components (302) are substantially equal and a tone generation unit for arranging the plurality of symbols (301) to form a plurality of long preambles (300) such that the plurality of long preambles (300) are tone-interleaved.
    Type: Application
    Filed: August 13, 2005
    Publication date: May 1, 2008
    Inventors: Ho Wang Fung, Sumei Sun, Chin Keong Ho, Ying Chang Liang, Yan Wu
  • Patent number: 7359733
    Abstract: A method for downlink beamforming in a frequency-division-duplex wireless communications system comprising a base station with an antenna array and terminals that are physically remote from said base station, the method comprising the steps of: receiving at said base station antenna array combinations of arriving uplink signals from said plurality of remote terminals, estimating an uplink beamforming weight vector for each of said terminals from said combinations of arriving uplink signal; identifying uplink nulls and an uplink main beam position from said uplink beamforming weight vector; transforming each of said uplink nulls to form a corresponding downlink null; generating a downlink beamforming weight vector from all downlink nulls; and transmitting a set of information signals from said base station antenna array according to said downlink. beamforming weights.
    Type: Grant
    Filed: August 3, 2001
    Date of Patent: April 15, 2008
    Inventors: Ying-Chang Liang, Francois Chin
  • Patent number: 7193983
    Abstract: A code division multiple access downlink receiver for providing wireless communication via a wireless channel between a base station and a mobile station in which the receiver is implemented. The receiver comprises a plurality of subchannels of which each conveys at least one signal received from the base station, and a cell searcher for receiving signals in the plurality of subchannels and retrieving therefrom a common code relating to a cell.
    Type: Grant
    Filed: January 17, 2002
    Date of Patent: March 20, 2007
    Assignee: Agency for Science, Technology and Research
    Inventors: Ying-Chang Liang, Po Shin Francois Chin
  • Patent number: 7167526
    Abstract: A method and apparatus for achieving combined beamforming and transmit diversity for frequency selective fading channels in a communication system having a base station with multiple transmit antennae and a mobile terminal with at least a single receive antenna, the method comprising the steps of: providing a signal to be transmitted; space-time encoding the signal to produce at least two separate signals, each on a respective output; feeding each output signal to a multiple access transmit processor to produce an output signal; applying respective selected transmit beamforming weights to each output signal; feeding the respective weighted signals to a signal combiner to perform a summing function of the signals and produce a signal for transmission; feeding the summed signal to each of the multiple transmit antennae for transmission; transmitting the signals over respective physical channels; receiving the transmitted signal at at least a single receive antenna; feeding the transmitted signal to a multiple a
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: January 23, 2007
    Assignee: National Univ. of Singapore
    Inventors: Ying-Chang Liang, Francois Po Shin Chin
  • Patent number: 7099299
    Abstract: A code division multiple access (CDMA) system and methods for processing symbol blocks of a spread signal in both frequency and time domains are described. A transmitter (10) of the CDMA system spreads pilot symbols and data of the symbol blocks to derive a spread sequence. Thereafter, the spread sequence is extended with a predetermined number of chips and pulse shaped for transmission as the spread signal. A receiver (400) of the CDMA system receives the spread signal, removes the predetermined number of chips and then orthogonally transforms the spread signal to the frequency domain to derive a transformed signal. The transformed signal is equalized in the frequency domain to derive an equalized signal. The equalized signal is then inverse orthogonally transformed to an output in the time domain. The output is then despreaded to derive the symbol blocks.
    Type: Grant
    Filed: March 4, 2002
    Date of Patent: August 29, 2006
    Assignee: Agency for Science, Technology and Research
    Inventors: Ying-Chang Liang, Francois Chin Po Shin, Appukuttan Nair Saraswathy Amma Madhukumar
  • Patent number: 6850741
    Abstract: A scheme for selecting two beams in a switched beam antenna system for providing downlink communications in a downlink channel, the switched beam antenna system providing uplink reception and downlink transmission is described. The scheme involves selecting a pair of beams based on the uplink reception of the switched beam antenna system, and determining from the pair of beams a corresponding pair of orthogonal beams. The scheme also involves providing the pair of orthogonal beams as a pair of transmit beams for the downlink transmission of the switched beam antenna system.
    Type: Grant
    Filed: April 4, 2002
    Date of Patent: February 1, 2005
    Assignee: Agency for Science, Technology and Research
    Inventors: Zhongding Lei, Po Shin Francois Chin, Ying Chang Liang
  • Publication number: 20040204105
    Abstract: A multiple distributed antenna access point (MDA/AP) system which compensates for wireless path loss and increases data throughput between AP and mobile user stations includes a central unit including one or more central antennas, a distributed antenna unit including multiple distributed antennas and an auxiliary unit interfacing the central unit with the distributed antenna unit, with each unit being separate or the central and auxiliary units being integrated. The central unit functions as a traditional access point and is operable in time division duplex (TDD) or frequency division duplex (FDD) mode. One or more central or distributed antennas are utilized to transmit and receive signals to and from the mobile user stations where selection of the antenna(s) used for a given mobile user station determines the throughput of the transmission.
    Type: Application
    Filed: August 14, 2002
    Publication date: October 14, 2004
    Inventors: Ying-Chang Liang, Fadi Boutros Baaklini, Richard Joseph Marino
  • Publication number: 20040071222
    Abstract: A method and apparatus for achieving combined beamforming and transmit diversity for frequency selective fading channels in a communication system having a base station with multiple transmit antennae and a mobile terminal with at least a single receive antenna, the method comprising the steps of: providing a signal to be transmitted; space-time encoding the signal to produce at least two separate signals, each on a respective output; feeding each output signal to a multiple access transmit processor to produce an output signal; applying respective selected transmit beamforming weights to each output signal; feeding the respective weighted signals to a signal combiner to perform a summing function of the signals and produce a signal for transmission; feeding the summed signal to each of the multiple transmit antennae for transmission; transmitting the signals over respective physical channels; receiving the transmitted signal at at least a single receive antenna; feeding the transmitted signal to a multiple a
    Type: Application
    Filed: January 18, 2002
    Publication date: April 15, 2004
    Applicant: National University of Singapore
    Inventors: Ying-Chang Liang, Francois Po Shin Chin
  • Patent number: 6694155
    Abstract: A method for downlink capacity enhancement in a wireless communications system that has a base station with antenna array and terminals that are physically remote from the base station comprises the steps of receiving at the base station antenna array combinations of arriving signals from the plurality of remote terminals, estimating an uplink channel covariance matrix (UCCM) for each of the terminals from the combinations of arriving signals, constructing from each UCCM a downlink channel covariance matrix (DCCM), calculating from the DCCM a downlink weight vector for each of the terminals, transmitting a set of information signals from the base station antenna array according to the downlink weight vectors.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: February 17, 2004
    Assignee: National University of Singapore
    Inventors: Francois Po Shin Chin, Ying Chang Liang
  • Publication number: 20030190897
    Abstract: A scheme for selecting two beams in a switched beam antenna system for providing downlink communications in a downlink channel, the switched beam antenna system providing uplink reception and downlink transmission is described. The scheme involves selecting a pair of beams based on the uplink reception of the switched beam antenna system, and determining from the pair of beams a corresponding pair of orthogonal beams. The scheme also involves providing the pair of orthogonal beams as a pair of transmit beams for the downlink transmission of the switched beam antenna system.
    Type: Application
    Filed: April 4, 2002
    Publication date: October 9, 2003
    Applicant: The National University of Singapore
    Inventors: Zhongding Lei, Po Shin Francois Chin, Ying Chang Liang
  • Publication number: 20030165131
    Abstract: A code division multiple access (CDMA) system and methods for processing symbol blocks of a spread signal in both frequency and time domains are described. A transmitter (10) of the CDMA system spreads pilot symbols and data of the symbol blocks to derive a spread sequence. Thereafter, the spread sequence is extended with a predetermined number of chips and pulse shaped for transmission as the spread signal. A receiver (400) of the CDMA system receives the spread signal, removes the predetermined number of chips and then orthogonally transforms the spread signal to the frequency domain to derive a transformed signal. The transformed signal is equalized in the frequency domain to derive an equalized signal. The equalized signal is then inverse orthogonally transformed to an output in the time domain. The output is then despreaded to derive the symbol blocks.
    Type: Application
    Filed: March 4, 2002
    Publication date: September 4, 2003
    Applicant: The National University of Singapore
    Inventors: Ying-Chang Liang, Francois Chin Po Shin, Appukuttan Nair Saraswathy Amma Madhukumar
  • Publication number: 20030133424
    Abstract: A code division multiple access downlink receiver for providing wireless communication via a wireless channel between a base station and a mobile station in which the receiver is implemented. The receiver comprises a plurality of subchannels of which each conveys at least one signal received from the base station, and a cell searcher for receiving signals in the plurality of subchannels and retrieving therefrom a common code relating to a cell.
    Type: Application
    Filed: January 17, 2002
    Publication date: July 17, 2003
    Inventors: Ying Chang Liang, Po Shin Francois Chin