Patents by Inventor Youjian Liu

Youjian 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: 9538483
    Abstract: Systems and methods are described for jointly optimizing communications in a multi-user network to maximize the weighted sum-rate of its data links. For example, embodiments seek to maximize overall link transmit rates, while minimizing link interference and/or noise in general multi-in multi-out (MIMO) interference networks having multiple interfering data links, each with one or more antennas at the transmitter and receiver. Novel algorithmic approaches, including an “iterative minimax” approach and a “dual link” approach, are described for solving the weighted sum-rate maximization in a manner that converges quickly and reliably on an optimal point. Some embodiments implement these approaches in a centralized transmission controller, while others implement these approaches in a distributed fashion.
    Type: Grant
    Filed: September 16, 2014
    Date of Patent: January 3, 2017
    Assignee: The Regents of the University of Colorado, A Body Corporate
    Inventors: Lijun Chen, Xing Li, Youjian Liu
  • Publication number: 20150146646
    Abstract: Systems and methods are described for jointly optimizing communications in a multi-user network to maximize the weighted sum-rate of its data links. For example, embodiments seek to maximize overall link transmit rates, while minimizing link interference and/or noise in general multi-in multi-out (MIMO) interference networks having multiple interfering data links, each with one or more antennas at the transmitter and receiver. Novel algorithmic approaches, including an “iterative minimax” approach and a “dual link” approach, are described for solving the weighted sum-rate maximization in a manner that converges quickly and reliably on an optimal point. Some embodiments implement these approaches in a centralized transmission controller, while others implement these approaches in a distributed fashion.
    Type: Application
    Filed: September 16, 2014
    Publication date: May 28, 2015
    Inventors: Lijun Chen, Xing Li, Youjian Liu
  • Patent number: 7583637
    Abstract: In an aspect of the method, a received data packet is decoded in order to determine a packet error rate value, and an average package error value for N received data packets is updated based on the determined packet error rate value. The updated average packet error rate value is then compared against a threshold value and a data rate request is issued based on this comparison. In another aspect, a response to a transmitted data packet is received, the response being related to an average packet error rate value. The average packet error rate value is compared against a threshold and a data rate is modified based on the comparison. In each of the above aspects, a data rate control margin that is used to overcome channel estimate errors resulting from transmission delays may be dynamically adjusted, e.g., in real time, in order to optimize system resources.
    Type: Grant
    Filed: January 31, 2003
    Date of Patent: September 1, 2009
    Assignee: Alcatel-Lucent USA Inc.
    Inventors: Kin Nang Lau, Youjian Liu, Martin H. Meyers, Susan Wu Sanders
  • Patent number: 7242727
    Abstract: In the method according to the present invention, a transmit power for each eigenbeam in a set of eigenbeams forming at least a portion of a multiple transmit antenna system is determined based on noise associated with each eigenbeam in the set of eigenbeams. The set of eigenbeams is for transmitting a number of parallel complex Gaussian channels.
    Type: Grant
    Filed: March 31, 2003
    Date of Patent: July 10, 2007
    Assignee: Lucent Technologies Inc.
    Inventors: Jung-Tao Liu, Youjian Liu, Ashok Rudrapatna
  • Publication number: 20040190643
    Abstract: In the method according to the present invention, a transmit power for each eigenbeam in a set of eigenbeams forming at least a portion of a multiple transmit antenna system is determined based on noise associated with each eigenbeam in the set of eigenbeams. The set of eigenbeams is for transmitting a number of parallel complex Gaussian channels.
    Type: Application
    Filed: March 31, 2003
    Publication date: September 30, 2004
    Inventors: Jung-Tao Liu, Youjian Liu, Ashok Rudrapatna
  • Publication number: 20040151122
    Abstract: In an aspect of the method, a received data packet is decoded in order to determine a packet error rate value, and an average package error value for N received data packets is updated based on the determined packet error rate value. The updated average packet error rate value is then compared against a threshold value and a data rate request is issued based on this comparison. In another aspect, a response to a transmitted data packet is received, the response being related to an average packet error rate value. The average packet error rate value is compared against a threshold and a data rate is modified based on the comparison. In each of the above aspects, a data rate control margin that is used to overcome channel estimate errors resulting from transmission delays may be dynamically adjusted, e.g., in real time, in order to optimize system resources.
    Type: Application
    Filed: January 31, 2003
    Publication date: August 5, 2004
    Inventors: Kin Nang Lau, Youjian Liu, Martin H. Meyers, Susan Wu Sanders