Patents by Inventor Gin Liu

Gin Liu 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: 7564895
    Abstract: Method and apparatus for retrieving the channel frequency response H(f), the noise N(f), measured at initialization and the signal to noise ratio SNR(f) measured at show time on a per bin basis, in the upstream or downstream direction. Initialization H(f) is used for analyzing the physical copper loop condition between tip and ring. Initialization N(f) is used for analyzing the crosstalk. Showtime SNR(f) is used for analyzing time dependent changes in crosstalk levels and line attenuation. The combination of H(f), N(f) and SNR(f) allows analysis of the line conditions for reaching the maximum data rate of a given loop, scheduling maintenance and plant update.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: July 21, 2009
    Assignee: Nortel Networks Limited
    Inventors: Gin Liu, Andrew Dempster, Mike M. J. Wingrove, Gwendolyn Kate Harris, Michel M. Darveau, Leslie Humphrey, Mohammed Reza Pakravan
  • Patent number: 7391780
    Abstract: Achieved bandwidths for existing subscribers are collected and organized into a statistical bandwidth table utilizing characterizing information, such as the Central Office (CO) that provided the service, the type of xDSL service that was provided, the primary, secondary, and other cable segments over which service was provided, and the subscriber loop length increment. To estimate anticipated bandwidth for a new subscriber, the new subscriber's characterizing information is obtained and used to select one or more entries from the statistical bandwidth table of statistical actual bandwidths achieved by other users that most closely matches the new subscriber's characterizing information. The statistical bandwidth information for the other similarly situated subscribers is used as an estimate bandwidth information for the new subscriber.
    Type: Grant
    Filed: April 16, 2003
    Date of Patent: June 24, 2008
    Assignee: Nortel Networks Limited
    Inventors: Gary T. Stone, Kim B. Crawford, Nelson M. Lee, Gin Liu, Johnny Fung, Michael A. Campbell
  • Patent number: 6785325
    Abstract: A DSL splitter providing test access to an interconnected subscriber loop and method are disclosed. The DSL splitter in a first test mode, provides access to allow testing of an interconnected subscriber loop by way of a DSL input. A disconnect in series with an associated low pass filter (LPF) disconnects POTS input. Such a splitter may similarly provide access to allow testing of the subscriber loop by way of the POTS input in a second test mode. In this second test mode, a by-pass by-passes the LPF, and a disconnect may disconnect an associated high pass filter (HPF) and DSL input. Preferably, the splitter only assumes its test modes after receipt of authorization from the other provider. The splitter may be controllable by way of a control circuit having an access port used to receive commands to have the splitter assume its normal, or first or second test mode. The splitter may assume its normal operating mode from a test mode, after expiry of a timeout timer.
    Type: Grant
    Filed: June 7, 2000
    Date of Patent: August 31, 2004
    Assignee: Nortel Networks Limited
    Inventors: Gin Liu, Anthony Peck, Alfred Haw
  • Patent number: 6760847
    Abstract: To identify interference from other data carrying subscriber loops (i.e., from loop disturbers), a power spectral density sample may be obtained from the subscriber loop under consideration based on at least one measurement while the loop is not transmitting data. The sample power spectral density may then be correlated with each one of a set of known power spectral densities. Each known power spectral density represents a power spectral density in a loop which is not transmitting data in the presence of one of (i) no subscriber loop disturbers, (ii) a particular subscriber loop disturber, and (iii) particular subscriber loop disturbers. Based on the correlations, subscriber loop disturbers may be recognized.
    Type: Grant
    Filed: April 13, 2000
    Date of Patent: July 6, 2004
    Assignee: Nortel Networks Limited
    Inventors: Gin Liu, Liqian Yao, Michael A. Campbell, Gary T. Stone
  • Publication number: 20030112763
    Abstract: A method and apparatus to determine performance of a subscriber loop includes using a database containing information pertaining to physical characteristics of a subscriber loop (or group of subscriber loops). Based on the information, a data communications speed of the subscriber loop is estimated. An actual data communications speed of the subscriber loop is determined and compared to the estimated data communications speed. The information in the database is updated based on the comparison.
    Type: Application
    Filed: December 17, 2001
    Publication date: June 19, 2003
    Inventors: Gin Liu, Michael A. Campbell
  • Publication number: 20020176544
    Abstract: A physical layer protocol is added to retrieve the in-band downstream ADSL channel frequency response H(f), the noise N(f), measured at initialization and the signal to noise ratio SNR(f) measured at show time on a per bin basis. Additionally retrieval of similar in-band information may be provided in the upstream direction. The definition of the message protocol for retrieving during show time the following ATU-R information on a per bin basis: In-band channel frequency response per bin HR(f) measured during the initialization referred back to the receiver tip and ring copper pair by the ARU-R; In-band noise estimation per bin NR(f) during the initialization referred back to the receiver tip and ring copper pair by the ATU-R; and the signal-to-noise ratio per bin SNRR(f) during show time referred back to the receiver tip and ring copper pair by the ATU-R. The values of SNRR(f) should be updated as they change.
    Type: Application
    Filed: December 21, 2001
    Publication date: November 28, 2002
    Inventors: Gin Liu, Andrew Dempster, Mike M. J. Wingrove, Gwendolyn Kate Harris, Michel M. Darveau, Leslie Humphrey, Mohammed Reza Pakravan
  • Publication number: 20020122552
    Abstract: A method and system for single-ended qualification of subscriber loops for xDSL services is disclosed. Subscriber loop database record are screened for disqualifying devices or services on the loop. If none are found, a set of predetermined electrical characteristics of the subscriber loop are derived from information in the database, or measured using test equipment at a central office end of the subscriber loop. The electrical Characteristics are used to assess the noise margin for the loop. If the assessed noise margin suggests that the loop does not qualify, the loop is modeled to assess if it will qualify in the presence of repeaters. The method and system are particularly well suited for qualifying a loop for HDSL or HDSL2 service.
    Type: Application
    Filed: December 29, 2000
    Publication date: September 5, 2002
    Applicant: NORTEL NETWORKS LIMITED
    Inventor: Gin Liu
  • Patent number: 6266395
    Abstract: A method and apparatus for single-ended qualification of subscriber loops for xDSL services is described. The method involves first screening a subscriber loop database record for disqualifying devices or services on the subscriber loop. If none are found, a set of predetermined electrical characteristics of the subscriber loop are derived from information in the database, or directly measured using test equipment at a central office end of the subscriber loop. The electrical characteristics are used to compute an available bandwidth on the subscriber loop for xDSL services. The advantage is the rapid and inexpensive qualification of subscriber loops which reduces response time to potential customer queries and facilitates deployment of xDSL services.
    Type: Grant
    Filed: September 3, 1999
    Date of Patent: July 24, 2001
    Assignee: Nortel Networks Limited
    Inventors: Gin Liu, Michael A. Campbell