Patents by Inventor Xiaoxin Qiu

Xiaoxin Qiu 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: 7035649
    Abstract: An on-demand message system includes a profile proxy server and a plurality of message servers coupled to a wireless network for sending messages to mobile users under conditions specified by the users and sellers. Users provide profile information specifying categories and conditions for which they will receive messages. Sellers also provide profile information specifying conditions under which they want messages to be sent. A multicast message is sent and processed by target users in response to a predetermined event, e.g., location update, conveying information related to a seller for which the target users have expressed an interest in receiving.
    Type: Grant
    Filed: January 8, 2004
    Date of Patent: April 25, 2006
    Assignee: AT&T Corp.
    Inventors: Li Fung Chang, Hui Luo, Xiaoxin Qiu
  • Publication number: 20050286467
    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: September 1, 2005
    Publication date: December 29, 2005
    Inventors: Li Chang, Kapil Chawla, Justin Chuang, Bruce McNair, Xiaoxin Qiu
  • Patent number: 6954465
    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: Grant
    Filed: February 22, 2001
    Date of Patent: October 11, 2005
    Assignee: AT&T Corp.
    Inventors: Li Fung Chang, Kapil K. Chawla, Justin Che-I Chuang, Bruce Edwin McNair, Xiaoxin Qiu
  • Patent number: 6950670
    Abstract: A wireless network includes transmission power and data rate adaptation based upon signal quality experienced by the user.
    Type: Grant
    Filed: October 31, 2001
    Date of Patent: September 27, 2005
    Assignee: AT&T Corp.
    Inventors: Li Fung Chang, Kapil K. Chawla, Justin Che-I Chuang, Xiaoxin Qiu
  • Publication number: 20050054296
    Abstract: The present invention implements a method and system for dynamically adapting the modulation and coding scheme for radio links in a wireless communications network based on a retransmission environment model in order to maximize throughput and most efficiently allocate bandwidth resources. The present invention encompasses a refined calculus and methodology for deriving the link adaptation thresholds in a retransmission environment using a complex model and analysis of the retransmission environment. The present invention holds particular application for wireless data communications as opposed to real time data services because it is based on a retransmission model applicable primarily for data services. A critical component of this new link adaptation system is a “no transmission” cutoff mode that is selected for SIR below a base threshold value. This new mode prevents system instability and misallocation of bandwidth in a wireless communication system.
    Type: Application
    Filed: October 22, 2004
    Publication date: March 10, 2005
    Inventors: Justin Chuang, Xiaoxin Qiu
  • Publication number: 20040253927
    Abstract: RF communications received by a wireless terminal from a servicing base station are used to determine the downlink quality report and implement link adaptation decisions. This involves first implementing an initial transmission scheme between the servicing base station and the wireless terminal. Next, a current downlink quality report corresponding to the initial transmission scheme is generated by the wireless terminal and received at the servicing base station. This downlink quality report is based in whole or in part on a bit-error probability (BEP). The current downlink quality report that corresponds to the initial transmission scheme is then compared to link adaptation thresholds.
    Type: Application
    Filed: April 20, 2004
    Publication date: December 16, 2004
    Inventor: Xiaoxin Qiu
  • Publication number: 20040253968
    Abstract: RF communications received by a wireless terminal from a servicing base station are used to determine the channel quality such as reported bit error probability (BEP). The RF communications may be in the form of RF bursts that are part of a data frame. An estimated BEP may be determined from the signal to noise ratio (SNR) of the RF bursts and or a sequence of soft decisions extracted from the RF bursts, and their historical performance. The SNR maps to an estimated BEP based upon the modulation format of the RF bursts. The soft decisions decode to produce a data block. When the soft decisions decoded favorably, the re-encoded data block produces a sequence of re-encoded decisions. Comparing the re-encoded decisions to the soft decisions yields a re-encoded bit error (RBER). The reported BEP may be based upon the estimated BEP, RBER, and/or RBER threshold. The RBER threshold may be adaptively incremented or decremented depending upon whether or not the RF communications were properly decoded.
    Type: Application
    Filed: May 14, 2004
    Publication date: December 16, 2004
    Inventors: Li Fung Chang, Yongqian Wang, Xiaoxin Qiu, Nelson R. Sollenberger
  • Publication number: 20040252647
    Abstract: RF communications received by a wireless terminal from a servicing base station are used to determine the BEP. These RF communications may be in the form of RF bursts that are part of a data frame. The signal to noise ratio (SNR) of the RF burst is determined and a sequence of soft decisions from the RF burst are extracted. The SNR maps to an estimated BEP based upon the modulation format and coding scheme of the RF burst. The soft decisions decode to produce a data block. When the soft decisions decoded favorably, the re-encoded data block produces a sequence of re-encoded decisions. Comparing the re-encoded decisions to the soft decisions yields a re-encoded bit error (RBER). When the decoding is unsuccessful, the BEP is estimated only upon the estimated BEP derived from the SNR. Otherwise, both the estimated BEP and RBER may be used to determine the BEP.
    Type: Application
    Filed: May 7, 2004
    Publication date: December 16, 2004
    Inventors: Li Fung Chang, Yongqian Wang, Huaiyu Zeng, Xiaoxin Qiu, Baoguo Yang
  • Patent number: 6823005
    Abstract: The present invention implements a method and system for dynamically adapting the modulation and coding scheme for radio links in a wireless communications network based on a retransmission environment model in order to maximize throughput and most efficiently allocate bandwidth resources. The present invention encompasses a refined calculus and methodology for deriving the link adaptation thresholds in a retransmission environment using a complex model and analysis of the retransmission environment. The present invention holds particular application for wireless data communications as opposed to real time data services because it is based on a retransmission model applicable primarily for data services. A critical component of this new link adaptation system is a “no transmission” cutoff mode that is selected for SIR below a base threshold value. This new mode prevents system instability and misallocation of bandwidth in a wireless communication system.
    Type: Grant
    Filed: August 9, 1999
    Date of Patent: November 23, 2004
    Assignee: AT&T Corp
    Inventors: Justin Che-I Chuang, Xiaoxin Qiu
  • Patent number: 6754506
    Abstract: A TDMA wireless communication system adjusts the power control target and transmission power based upon link quality to enhance voice capacity. The power can be adjusted in response to the average SNIR and number of decoding errors in a link quality reporting period. The power control target can be increased and decreased in discrete intervals after evaluating the number of decoding errors in the reporting period. The transmission power can be adjusted towards the new power control target based upon the average SNIR.
    Type: Grant
    Filed: February 16, 2001
    Date of Patent: June 22, 2004
    Assignee: AT&T Wireless Services, Inc.
    Inventors: Li Fung Chang, Kapil K. Chawla, Justin Chi-I Chuang, Zoran Kostic, Xiaoxin Qiu, Nelson Ray Sollenberger, Shailender B. Timiri
  • Patent number: 6681114
    Abstract: An on-demand message system includes a profile proxy server and a plurality of message servers coupled to a wireless network for sending messages to mobile users under conditions specified by the users and sellers. Users provide profile information specifying categories and conditions for which they will receive messages. Sellers also provide profile information specifying conditions under which they want messages to be sent. A multicast message is sent and processed by target users in response to a predetermined event, e.g., location update, conveying information related to a seller for which the target users have expressed an interest in receiving.
    Type: Grant
    Filed: December 6, 2000
    Date of Patent: January 20, 2004
    Assignee: AT&T Corp.
    Inventors: Li Fung Chang, Hui Luo, Xiaoxin Qiu
  • Patent number: 6657982
    Abstract: A method and apparatus for scheduling transmissions between a plurality of communications sites within a communications system. The communications system provides service to a service area which is divided into sectors. Each sector is assigned a time subframe in a pattern where adjacent sectors use different subframes. Communications sites within each sector communicate packets of information in at least one time subframe according to a schedule to minimize interference from other communications sites.
    Type: Grant
    Filed: January 27, 2000
    Date of Patent: December 2, 2003
    Assignee: AT&T Corp.
    Inventors: Thomas K. Fong, Paul Shala Henry, Kin K. Leung, Xiaoxin Qiu, Nemmara K. Shankaranarayanan
  • Publication number: 20030207695
    Abstract: A TDMA wireless communication system adjusts the power control target and transmission power based upon link quality to enhance voice capacity. The power can be adjusted in response to the average SNIR and number of decoding errors in a link quality reporting period. The power control target can be increased and decreased in discrete intervals after evaluating the number of decoding errors in the reporting period. The transmission power can be adjusted towards the new power control target based upon the average SNIR.
    Type: Application
    Filed: February 16, 2001
    Publication date: November 6, 2003
    Inventors: Li Fung Chang, Kapil K. Chawla, Justin Chi-I Chuang, Zoran Kostic, Xiaoxin Qiu, Nelson Ray Sollenberger, Shailender B. Timiri
  • 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: 6532225
    Abstract: An arrangement where, in addition to the control channels that are used to set up sessions, there is a logically and physically separate and independent set of control channels that can be used as session control channels. Illustratively, the physical GSM frame arrangement that employs 8 logical slots is used, with one slot both in the uplink and downlink dedicated to these separate control channels. In the downlink, such a control channel provides channel grant information, requests to make and transmit power measurements, poll mobile units, etc. In the uplink, such a control channel can be used to request access to a traffic channel, to report on power measurements, to request special hand-off handling, to respond to polling, etc. Because the uplink session control channel does not need to carry a significant amount of information, the GSM slot can be divided into minislots, with each minislot constituting a session control channel for a group of mobile units.
    Type: Grant
    Filed: July 27, 1999
    Date of Patent: March 11, 2003
    Assignee: AT&T Corp
    Inventors: Li Fung Chang, Kapil K. Chawla, Justin C. Chuang, Xiaoxin Qiu, Nelson R. Sollenberger
  • Patent number: 6501765
    Abstract: The invention provides a method and apparatus for end-users to allocate a communication medium locally without requiring a central arbitration device while guaranteeing access to the end-users. The end-users bid for control of an upstream data channel by concurrently transmitting auction data and address data on a first upstream signaling channel and a second upstream signaling channel. An end-user gains control of the upstream data channel when data received from the first and second downstream signaling channels match the auction and address bits. When it is determined that the end-user lost the bid, the end-user backs off from the first and second upstream signaling channels and refrains from bidding until the first and second upstream signaling channels become quiet.
    Type: Grant
    Filed: September 1, 1998
    Date of Patent: December 31, 2002
    Assignee: AT&T Corp.
    Inventors: Xiaolin Lu, Xiaoxin Qiu
  • Patent number: 6501785
    Abstract: This invention provides a dynamic frequency hopping system that utilizes information from multiple base stations. The system assigns frequency hopping patterns based on current interference and traffic environments to avoid interference thus gaining the benefits of interference averaging and interference avoidance. The system imposes less stringent measurement requirements on terminals (wireless mobile devices) because many measurement requirements are replaced by generating estimates based on measurement data received from other base stations within a base station neighborhood. The system may continuously verify that the frequency hopping patterns assigned to the links of the system optimizes system performance. The system compares system performance of possible frequency hopping patterns against currently assigned frequency hopping pattern to optimize system performance.
    Type: Grant
    Filed: December 28, 1999
    Date of Patent: December 31, 2002
    Assignee: AT&T Corp.
    Inventors: Li Fung Chang, Kapil K. Chawla, Justin C. Chuang, Zoran Kostic, Nelson Sollenberger, Xiaoxin Qiu
  • Publication number: 20020172219
    Abstract: The invention provides a method and apparatus for end-users to allocate a communication medium locally without requiring a central arbitration device while guaranteeing access to the end-users. The end-users bid for control of an upstream data channel by concurrently transmitting auction data and address data on a first upstream signaling channel and a second upstream signaling channel. An end-user gains control of the upstream data channel when data received from the first and second downstream signaling channels match the auction and address bits. When it is determined that the end-user lost the bid, the end-user backs off from the first and second upstream signaling channels and refrains from bidding until the first and second upstream signaling channels become quiet.
    Type: Application
    Filed: May 20, 2002
    Publication date: November 21, 2002
    Applicant: AT&T CORP.
    Inventors: Xiaolin Lu, 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
  • Publication number: 20020115459
    Abstract: A Kalman-filter power control method is applied to a packet voice service in a wireless network based on interference tracking and predictions. An Enhanced Data for GSM Evolution (EDGE) system is used as an illustrative platform for the invention. The power-control method significantly improves the spectral efficiency by enabling the 1/3 frequency reuse while maintaining a stringent requirement of 2% packet loss probability for voice service. For allocated spectrum of 1.8, 3.6 and 5.4 MHz, the 1/3 reuse with the Kalman power control can yield 102.5%, 49.5% and 32.5% improvement in spectral efficiency over the 3/9 reuse, respectively.
    Type: Application
    Filed: February 22, 2001
    Publication date: August 22, 2002
    Inventors: Justin Che-l Chuang, Kin K. Leung, Xiaoxin Qiu, Li-Chun Wang, Shailehnder Timiri