Patents by Inventor Venkata N. Padmanabhan

Venkata N. Padmanabhan 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: 7296088
    Abstract: A system and methodologies are disclosed for determining the geographic location of an Internet host. A first method infers host location based on the DNS names of the host of interest or other nearby network nodes. A second method employs network delay measurements from geographically distributed locations to triangulate the coordinates of the host. A third method couples partial host-to-location mapping information obtained from one or more sources with BGP or other routing information in order to infer location of the host of interest.
    Type: Grant
    Filed: May 4, 2001
    Date of Patent: November 13, 2007
    Assignee: Microsoft Corporation
    Inventors: Venkata N. Padmanabhan, Lakshminarayanan Subramanian
  • Patent number: 7275111
    Abstract: A method of reducing bandwidth limitations to send events to a set of interested clients within a pre-defined time period as quickly and fairly as possible. The clients can be re-distributed among the servers in a network such that the delay due to server overloading is minimized by moving clients from an overloaded server to a server with available bandwidth. In addition, the latency of client-server communications can be incorporated into an estimation of download times, and the servers can then initiate delivery to respective clients based on those download times. By staggering the send times to account for heterogeneous latencies, more clients can receive the event at the same time, and a fairness of distribution can be achieved.
    Type: Grant
    Filed: April 20, 2006
    Date of Patent: September 25, 2007
    Assignee: Microsoft Corporation
    Inventors: Luis Felipe Cabrera, Venkata N Padmanabhan
  • Patent number: 7222285
    Abstract: A data sequence may be encoded in a plurality of layers of multiple description coding. The layers of multiple description coding may include a first and a second layer of multiple description coding. The first layer of multiple description coding may include an initial part of a data sequence as well as forward error correction code for the initial part. The second layer of multiple description coding may include a next part of the data sequence as well as forward error correction code for the next part. A first set of data sequence breakpoints may be determined for the first layer of multiple description coding. A second set of data sequence breakpoints may be determined for the second layer. The data sequence may be encoded in the plurality of layers of multiple description coding as a function of the first and second sets of data sequence breakpoints.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: May 22, 2007
    Assignee: Microsoft Corporation
    Inventors: Philip Andrew Chou, Venkata N. Padmanabhan, Helen Wang
  • Patent number: 7096200
    Abstract: A system and method is provided for evaluating the effectiveness of data encryption for hiding the identity of the source of Web traffic. A signature is constructed from encrypted Web traffic for a Web page sent by a target Web site, and the signature is compared with archived traffic signatures obtained by accessing various Web pages of interest in advance. If the signature of the detected encrypted Web traffic matches a stored traffic signature beyond a pre-set statistical threshold, a positive match is found, and the source of the traffic is identified. Countermeasures for reducing the reliability of source identification based on traffic signature matching are provided.
    Type: Grant
    Filed: April 23, 2002
    Date of Patent: August 22, 2006
    Assignee: Microsoft Corporation
    Inventors: Yi-Min Wang, Qixiang Sun, Daniel R. Simon, Wilfred Russell, Lili Qiu, Venkata N. Padmanabhan
  • Patent number: 7085848
    Abstract: A method of reducing bandwidth limitations to send events to a set of interested clients within a pre-defined time period as quickly and fairly as possible. The clients can be re-distributed among the servers in a network such that the delay due to server overloading is minimized by moving clients from an overloaded server to a server with available bandwidth. In addition, the latency of client-server communications can be incorporated into an estimation of download times, and the servers can then initiate delivery to respective clients based on those download times. By staggering the send times to account for heterogeneous latencies, more clients can receive the event at the same time, and a fairness of distribution can be achieved.
    Type: Grant
    Filed: March 15, 2002
    Date of Patent: August 1, 2006
    Assignee: Microsoft Corporation
    Inventors: Luis Felipe Cabrera, Venkata N. Padmanabhan
  • Patent number: 7020475
    Abstract: A method for locating a user in a wireless network is disclosed. A mobile computer seeking to determine its location within a building detects the signal strength of one or more wireless base stations placed at known locations throughout the building. The mobile computer uses this measured signal strength to determine its location via a signal-strength-to-location table look-up. A table of known locations within the building and the base station signal strength at those locations is searched to find the most similar stored signal strength to the signal strength detected. The location corresponding to the most similar stored signal strength is determined to be the current location of the mobile computer. Alternatively, a number of signal strengths from the table can be used and the corresponding locations can be spatially averaged to determine the location of the mobile computer.
    Type: Grant
    Filed: November 15, 2004
    Date of Patent: March 28, 2006
    Assignee: Microsoft Corporation
    Inventors: Paramvir Bahl, Venkata N. Padmanabhan
  • Patent number: 6898518
    Abstract: Humans identify location and directions based on visual cues, such as landmarks, rather than a precise coordinate grid. A database of landmarks can be used to determine the location of a user who can merely describe their location in the same manner they would to any human contact. The location of the user can be determined based on the landmarks described in the input, and the areas from which all of those landmarks are visible. Various databases can be used, including text-based and three-dimensional. Similarly, various mechanisms can be used to determine the user's location, including hierarchical approaches, query optimization approaches, and visibility percentage approaches. Ultimately, the user's location can be determined without the need for expensive, dedicated infrastructure, without compromising the user's security, and without subjecting the user to system outages.
    Type: Grant
    Filed: July 12, 2004
    Date of Patent: May 24, 2005
    Assignee: Microsoft Corporation
    Inventor: Venkata N. Padmanabhan
  • Patent number: 6839560
    Abstract: A method for locating a user in a wireless network is disclosed. A mobile computer seeking to determine its location within a building detects the signal strength of one or more wireless base stations placed at known locations throughout the building. The mobile computer uses this measured signal strength to determine its location via a signal-strength-to-location table look-up. A table of known locations within the building and the base station signal strength at those locations is searched to find the most similar stored signal strength to the signal strength detected. The location corresponding to the most similar stored signal strength is determined to be the current location of the mobile computer. Alternatively, a number of signal strengths from the table can be used and the corresponding locations can be spatially averaged to determine the location of the mobile computer.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: January 4, 2005
    Assignee: Microsoft Corporation
    Inventors: Paramvir Bahl, Venkata N. Padmanabhan
  • Publication number: 20040243303
    Abstract: Humans identify location and directions based on visual cues, such as landmarks, rather than a precise coordinate grid. A database of landmarks can be used to determine the location of a user who can merely describe their location in the same manner they would to any human contact. The location of the user can be determined based on the landmarks described in the input, and the areas from which all of those landmarks are visible. Various databases can be used, including text-based and three-dimensional. Similarly, various mechanisms can be used to determine the user's location, including hierarchical approaches, query optimization approaches, and visibility percentage approaches. Ultimately, the user's location can be determined without the need for expensive, dedicated infrastructure, without compromising the user's security, and without subjecting the user to system outages.
    Type: Application
    Filed: July 12, 2004
    Publication date: December 2, 2004
    Applicant: Microsoft Corporation
    Inventor: Venkata N. Padmanabhan
  • Patent number: 6799047
    Abstract: A method for locating a user in a wireless network is disclosed. A mobile computer which seeks to determine its location within a building detects the signal strength of one or more wireless base stations placed at known locations throughout the building. An environmentally profiled table of known locations within the building and the base station signal strength at those locations is searched to find the stored signal strength most similar to the signal strength detected. The location corresponding to the most similar stored signal strength is determined to be the current location of the mobile computer.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: September 28, 2004
    Assignee: Microsoft Corporation
    Inventors: Paramvir Bahl, Venkata N. Padmanabhan
  • Patent number: 6766245
    Abstract: Humans identify location and directions based on visual cues, such as landmarks, rather than a precise coordinate grid. A database of landmarks can be used to determine the location of a user who can merely describe their location in the same manner they would to any human contact. The location of the user can be determined based on the landmarks described in the input, and the areas from which all of those landmarks are visible. Various databases can be used, including text-based and three-dimensional. Similarly, various mechanisms can be used to determine the user's location, including hierarchical approaches, query optimization approaches, and visibility percentage approaches. Ultimately, the user's location can be determined without the need for expensive, dedicated infrastructure, without compromising the user's security, and without subjecting the user to system outages.
    Type: Grant
    Filed: March 14, 2002
    Date of Patent: July 20, 2004
    Assignee: Microsoft Corporation
    Inventor: Venkata N. Padmanabhan
  • Publication number: 20040064725
    Abstract: A computer in a network runs a verification procedure in which it sends data packets to another computer in the network. Some or all of the data packets contain, either individually or collectively, a secret piece of information, such as a secret code. The computer then makes a determination regarding the network links between it and the other computer. If, for example, the other computer is able to respond by providing the secret piece of information back, then the computer sending the data packets concludes that the devices along the network links en route to the other computer are properly forwarding data packets.
    Type: Application
    Filed: September 18, 2002
    Publication date: April 1, 2004
    Applicant: Microsoft Corporation
    Inventors: Venkata N. Padmanabhan, Daniel R. Simon
  • Publication number: 20040044759
    Abstract: A computer network has links for carrying data among computers, including one or more client computers. Packet loss rates are determined for the client computers and, a system of equations is set up expressing the relationship between the loss rates at the client computers and the loss rates at the links. The system of equations is then solved using one or more linear programming techniques, and optimized by making an effort to find the most parsimonious solution.
    Type: Application
    Filed: February 7, 2003
    Publication date: March 4, 2004
    Applicant: Microsoft Corporation
    Inventors: Venkata N. Padmanabhan, Lili Qiu
  • Publication number: 20040044764
    Abstract: A computer network has links for carrying data among computers, including one or more client computers. Packet loss rates are determined for the client computers and, based on the loss rates, a number of possible sets of solutions for the loss rates at each of the links are generated. The sets of possible solutions are subjected to a statistical analysis. Based on the results of the analysis, a determination is made regarding which of the links are excessively lossy.
    Type: Application
    Filed: January 31, 2003
    Publication date: March 4, 2004
    Applicant: Microsoft Corporation
    Inventors: Venkata N. Padmanabhan, Lili Qiu
  • Publication number: 20040044765
    Abstract: A computer network has links for carrying data among computers, including one or more client computers. Packet loss rates are determined for the client computers. Probability distributions for the loss rates of each of the client computers are then developed using various mathematical techniques. Based on an analysis of these probability distributions, a determination is made regarding which of the links are excessively lossy.
    Type: Application
    Filed: March 3, 2003
    Publication date: March 4, 2004
    Applicant: Microsoft Corporation
    Inventors: Christopher A. Meek, Venkata N. Padmanabhan, Lili Qiu, Jiahe Wang, David B. Wilson, Christian H. Borgs, Jennifer T. Chayes, David E. Heckerman
  • Publication number: 20030200175
    Abstract: A system and method is provided for evaluating the effectiveness of data encryption for hiding the identity of the source of Web traffic. A signature is constructed from encrypted Web traffic for a Web page sent by a target Web site, and the signature is compared with archived traffic signatures obtained by accessing various Web pages of interest in advance. If the signature of the detected encrypted Web traffic matches a stored traffic signature beyond a pre-set statistical threshold, a positive match is found, and the source of the traffic is identified. Countermeasures for reducing the reliability of source identification based on traffic signature matching are provided.
    Type: Application
    Filed: April 23, 2002
    Publication date: October 23, 2003
    Applicant: Microsoft Corporation
    Inventors: Yi-Min Wang, Qixiang Sun, Daniel R. Simon, Wilfred Russell, Lili Qiu, Venkata N. Padmanabhan
  • Publication number: 20030188188
    Abstract: To provide a fairness of distribution, an encrypted event, containing information not intended for release prior to a release time, can be sent to clients prior to the release time. In such a manner the bulk of the information can be transferred to the clients without concern to the duration of the transfer. At the release time, a small decryption key can be sent, either from a central sever, or from multiple server, utilizing multiple network paths to provide for the greatest likelihood that each client will receive the decryption key with a minimum of delay. Each client is thereby provided access to the information at approximately the same time, regardless of the bandwidth available to each client.
    Type: Application
    Filed: March 15, 2002
    Publication date: October 2, 2003
    Applicant: Microsoft Corporation
    Inventors: Venkata N. Padmanabhan, Luis Felipe Cabrera
  • Publication number: 20030177183
    Abstract: A method of reducing bandwidth limitations to send events to a set of interested clients within a pre-defined time period as quickly and fairly as possible. The clients can be re-distributed among the servers in a network such that the delay due to server overloading is minimized by moving clients from an overloaded server to a server with available bandwidth. In addition, the latency of client-server communications can be incorporated into an estimation of download times, and the servers can then initiate delivery to respective clients based on those download times. By staggering the send times to account for heterogeneous latencies, more clients can receive the event at the same time, and a fairness of distribution can be achieved.
    Type: Application
    Filed: March 15, 2002
    Publication date: September 18, 2003
    Applicant: Microsoft Corporation
    Inventors: Luis Felipe Cabrera, Venkata N. Padmanabhan
  • Publication number: 20030176965
    Abstract: Humans identify location and directions based on visual cues, such as landmarks, rather than a precise coordinate grid. A database of landmarks can be used to determine the location of a user who can merely describe their location in the same manner they would to any human contact. The location of the user can be determined based on the landmarks described in the input, and the areas from which all of those landmarks are visible. Various databases can be used, including text-based and three-dimensional. Similarly, various mechanisms can be used to determine the user's location, including hierarchical approaches, query optimization approaches, and visibility percentage approaches. Ultimately, the user's location can be determined without the need for expensive, dedicated infrastructure, without compromising the user's security, and without subjecting the user to system outages.
    Type: Application
    Filed: March 14, 2002
    Publication date: September 18, 2003
    Applicant: Microsoft Corporation
    Inventor: Venkata N. Padmanabhan