Patents by Inventor Justin Che-I Chuang

Justin Che-I Chuang 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: 20030083088
    Abstract: A wireless network includes transmission power and data rate adaptation based upon signal quality experienced by the user.
    Type: Application
    Filed: October 31, 2001
    Publication date: May 1, 2003
    Inventors: Li Fung Chang, Kapil K. Chawla, Justin Che-I Chuang, Xiaoxin Qiu
  • Patent number: 6459901
    Abstract: This invention provides wireless resource allocation techniques where the wireless network resource allocation is based on maximum system gain. System gain may be the difference between a maximum performance (e.g., throughput rate) for a requested link and a performance loss of all currently active links affected by the requested link. A currently active link is affected if the requested link is within its link neighborhood. Wireless network resources are allocated to optimize system performance. Inter-base communication may be used to facilitate information exchange among base stations to optimize system performance. The performance loss experienced by any currently active link is called damage to that link. Damage may be determined in a pair-wise fashion based on a nominal performance which may be defined as the performance of a link if interference is experienced only from links which are outside the link neighborhood of the link or as a system parameter.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: October 1, 2002
    Assignee: AT&T Corp.
    Inventors: Kapil K. Chawla, Justin Che-I Chuang, Xiaoxin Qiu, Nelson Ray Sollenberger
  • Patent number: 6339450
    Abstract: A method and system for maintaining the quality of video transported over wireless channels uses a transcoder to modify and maintain the optical resilience of an encoded bitstream. The transcoder increases the spatial resilience by reducing the number of blocks per slice, and increases the temporal resilience by increasing the proportion of I-blocks that are transmitted in each frame. Also, the transcoder maintains the same input bit rate by dropping less significant coefficients as it increases resilience. The transcoder of the present invention maintains the resilience at an optimal level to accommodate the prevailing channel conditions as measured by the BER of the wireless channel. Rate distortion theory is applied to determine the optimal allocation of bit rate among spatial resilience, temporal resilience and source rate, where it is has been found that the optimal allocation of the present invention (which occurs in near-real time) provides nearly the same result as doing an exhaustive search.
    Type: Grant
    Filed: September 21, 1999
    Date of Patent: January 15, 2002
    Assignees: AT&T Corp, Columbia University
    Inventors: Shih-Fu Chang, Justin Che-I Chuang, Gustavo De Los Reyes, Amy Ruth Reibman
  • Publication number: 20010048691
    Abstract: This invention provides interference predictions, suitable for least interference dynamic channel assignment use or other frequency hopping uses by de-coupling the time slot assignment and the frequency hopping pattern assignment. In particular, a least interfered time slot is selected based on an aggregate interference measurement performed across an entire transmission band or a pre-specified range of frequencies in the transmission band. A user is assigned a least interfered time slot and provided an appropriate frequency hopping pattern.
    Type: Application
    Filed: February 22, 2001
    Publication date: December 6, 2001
    Inventors: Li Fung Chang, Kapil K. Chawla, Justin Che-I Chuang, Bruce Edwin McNair, Xiaoxin Qiu
  • Patent number: 6052594
    Abstract: A method and system for controlling media access in which a paging message is transmitted from a base station to a wireless station when a data packet is received for downlink transmission to the wireless station. The base station is one of a plurality of base stations and the wireless station is associated with the base station. In response to the paging message, a level of each of a plurality of pilot frequency signals is detected at the wireless station. Each pilot frequency corresponds to a downlink traffic channel and is transmitted by base stations to which the downlink traffic channel is assigned. The wireless station generates a list of preferred traffic channels based on a priority order of traffic channels and on detected levels of the pilot frequency signals, and transmits the list to the associated base station.
    Type: Grant
    Filed: April 30, 1997
    Date of Patent: April 18, 2000
    Assignee: AT&T Corp.
    Inventors: Justin Che-I Chuang, Nelson Ray Sollenberger