Patents by Inventor Brian Donald Hart

Brian Donald Hart 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: 8559323
    Abstract: Techniques are provided herein to allow a wireless network access point (AP) to more fully use its bandwidth in order to leverage the different bandwidth capabilities of different types of wireless client devices that the AP serves. The AP generates control parameters for usage of a plurality of channels in a bandwidth during a downlink transmission interval. The control parameters comprise information indicating channel assignments that result in multiple downlink transmissions that at least partially overlap in time to different wireless client devices according to their respective bandwidth capabilities. The AP transmits the control parameters in a control frame in advance of the downlink transmission interval on each of the plurality of channels in the bandwidth.
    Type: Grant
    Filed: June 21, 2010
    Date of Patent: October 15, 2013
    Assignee: Cisco Technology, Inc.
    Inventor: Brian Donald Hart
  • Publication number: 20130100952
    Abstract: Described herein are techniques that provide for the transmission of a multicast stream that can resend frames that were not received using the partial state block acknowledgement mechanism. In an example embodiment, an access point reserves a channel for a transmission opportunity of a sufficient length to allow the sending of multicast data, block acknowledgement request, and receipt of a block acknowledgement. Optionally, the transmission opportunity may be of sufficient length to enable packets that re resent to be sent during the transmission opportunity, thereby preventing other stations on the channel from gaining control of the channel. Alternatively the access point may employ an appropriate backoff between TXOPs to AP prevent (T)DLS traffic to the recipients of the multicast stream. The access point does not send any frames from other queues during the transmission opportunity.
    Type: Application
    Filed: October 25, 2011
    Publication date: April 25, 2013
    Inventors: Brian Donald HART, Santosh Pandey, Rohit Suri
  • Patent number: 8411807
    Abstract: A mid-packet detection technique is provided that detects a packet with periodic repetitions of a fixed duration at a point in time of the packet other than a start-of-packet pattern, e.g., a preamble, associated with the packet. The process performs packet detection without detecting a preamble and does not require carrier frequency recovery, timing recovery (synchronization) or channel estimation. In one embodiment, a doubly differential matched filter autocorrelation of the received signal is computed and used as a metric for packet detection when the preamble is not observed or to complement preamble detection. The metric is compared to a threshold to indicate detection of a packet.
    Type: Grant
    Filed: September 2, 2008
    Date of Patent: April 2, 2013
    Assignee: Cisco Technology, Inc.
    Inventors: Raghuram Rangarajan, Brian Donald Hart, Paul J. Stager
  • Patent number: 8369657
    Abstract: Techniques are provided for selecting channels for a wider bandwidth operation mode of a wireless network, such as wireless network that operates in accordance with the IEEE 802.11n amendment. Alignments of so-called primary and secondary channels are selected to mitigate interference. Interfering sources, such as other transceivers or external interferers, or the energy from their transmissions, are identified and channels are selected. The selected channels are analyzed to determine whether primary-secondary channel assignments for the selected channels are feasible.
    Type: Grant
    Filed: March 6, 2012
    Date of Patent: February 5, 2013
    Assignee: Cisco Technology, Inc.
    Inventors: Douglas Chan, Brian Donald Hart, Bretton Douglas
  • Patent number: 8369305
    Abstract: At a plurality of first devices, wireless transmissions are received at different locations in a region where multiple target devices may be emitting. Identifier data associated with reception of emissions from target devices at multiple first devices is generated. Similar identifier data associated with received emissions at multiple first devices are grouped together into a cluster record that potentially represents the same target device detected by multiple first devices. Data is stored that represents a plurality of cluster records from identifier data associated with received emissions made over time by multiple first devices. The cluster records are analyzed over time to correlate detections of target devices across multiple first devices.
    Type: Grant
    Filed: June 30, 2008
    Date of Patent: February 5, 2013
    Assignee: Cisco Technology, Inc.
    Inventors: Neil R. Diener, Gary L. Sugar, Brian Donald Hart, Igal Gutkin, David Kloper
  • Publication number: 20130010731
    Abstract: In an example embodiment described herein is an apparatus comprising a wireless transceiver and channel selection logic coupled to the wireless transceiver and operable to select an operating frequency for the wireless transceiver. The channel selection logic is configured to reserve a dedicated channel having a special identifier. The channel selection logic is configured to have the wireless transceiver advertise the dedicated service on a normal operating frequency. The channel selection logic is responsive to receiving a request from a wireless device via the wireless transceiver on the normal operating frequency to use the dedicated channel to switch to the dedicated channel and establish communications with the wireless device on the dedicated channel.
    Type: Application
    Filed: September 14, 2012
    Publication date: January 10, 2013
    Inventors: Neil Robert DIENER, Abhijit Kumar CHOUDHURY, Brian Donald HART, David S. STEPHENSON
  • Patent number: 8335173
    Abstract: A device whose location is to be determined (target device) generates a plurality of frames (messages) and time of departure (TOD) timestamp information indicating when the target device transmits the plurality of frames in a sequence or burst. The target device transmits the plurality of frames and the TOD information, wherein the plurality of frames are transmitted such that at least two of the frames are on different radio frequency (RF) channels. Within a sequence or burst (or across multiple sequences or bursts), multiple widely spaced transmissions on the same channel are included to allow for estimation of the crystal frequency offset of the transmitting device. The TOD information included in the transmitted packets allows devices that receive the packets not to change their channels of operation solely for the purpose of receiving packets from the device to be located.
    Type: Grant
    Filed: July 7, 2008
    Date of Patent: December 18, 2012
    Assignee: Cisco Technology, Inc.
    Inventors: Brian Donald Hart, Paul J. Stager, Allan Thomson
  • Publication number: 20120314583
    Abstract: In accordance with an example embodiment, there is disclosed herein a coexistence mechanism for multiple channels. A plurality of channels are monitored to determine which channels are available for communications. Upon receiving a request to establish communications on a channel set within the plurality of channels, a response is sent to the request on at least one in the channel set. The response comprises data representative of which channels from the channel set are available for communications. Optionally, the response may include data indicating how long the unavailable channels will be occupied.
    Type: Application
    Filed: June 13, 2011
    Publication date: December 13, 2012
    Inventors: Brian Donald HART, Raghuram Rangarajan, Ahmadreza Hedayat
  • Patent number: 8325696
    Abstract: In an example embodiment described herein is an apparatus comprising a wireless transceiver and channel selection logic coupled to the wireless transceiver and operable to select an operating frequency for the wireless transceiver. The channel selection logic is configured to reserve a dedicated channel having a special identifier. The channel selection logic is configured to have the wireless transceiver advertise the dedicated service on a normal operating frequency. The channel selection logic is responsive to receiving a request from a wireless device via the wireless transceiver on the normal operating frequency to use the dedicated channel to switch to the dedicated channel and establish communications with the wireless device on the dedicated channel.
    Type: Grant
    Filed: July 29, 2009
    Date of Patent: December 4, 2012
    Assignee: Cisco Technology, Inc.
    Inventors: Neil Robert Diener, Abhijit Kumar Choudhury, Brian Donald Hart, David S. Stephenson
  • Publication number: 20120280714
    Abstract: In an example embodiment, a method for synchronizing clocks between a plurality of clocked devices where one of the plurality of clocked devices is not directly synchronized with another of the plurality of clocked devices. Clock offset and a clock drift between a first clock associated with a first device and a second clock associated with a second is directly determined based on signals exchanged between the first and second devices. Clock offset and clock drift between the second clock and a third clock associated with a third device is directly determined based on signals exchanged between the second and third devices. A clock offset and clock drift between the first clock and third clock is determined based on a difference between the clock offset and drift between the first and second clocks and the clock offset and drift between the second and third clocks.
    Type: Application
    Filed: July 18, 2012
    Publication date: November 8, 2012
    Inventors: Matthew Aaron SILVERMAN, Paul Jeffrey Stager, Brian Donald Hart
  • Patent number: 8248233
    Abstract: In one embodiment, a method includes obtaining location information associated with a remote device, and processing the location information. Processing the location information includes determining if the remote device is mobile. The method also includes configuring a filter such that at least one parameter indicates that the remote device is mobile if the remote device is mobile, and configuring the filter such that the at least one parameter indicates that the remote device is approximately stationary if the remote device is not mobile. The filter is applied to the location information to generate a filtered location estimate which is arranged to estimate a location of the remote device.
    Type: Grant
    Filed: April 27, 2009
    Date of Patent: August 21, 2012
    Assignee: Cisco Technology, Inc.
    Inventors: Matthew Aaron Silverman, Santosh G. Pandey, Brian Donald Hart
  • Patent number: 8249049
    Abstract: In an example embodiment, a method for synchronizing clocks between a plurality of clocked devices where one of the plurality of clocked devices is not directly synchronized with another of the plurality of clocked devices. Clock offset and a clock drift between a first clock associated with a first device and a second clock associated with a second is directly determined based on signals exchanged between the first and second devices. Clock offset and clock drift between the second clock and a third clock associated with a third device is directly determined based on signals exchanged between the second and third devices. A clock offset and clock drift between the first clock and third clock is determined based on a difference between the clock offset and drift between the first and second clocks and the clock offset and drift between the second and third clocks.
    Type: Grant
    Filed: March 17, 2009
    Date of Patent: August 21, 2012
    Assignee: Cisco Technology, Inc.
    Inventors: Matthew Aaron Silverman, Paul Jeffrey Stager, Brian Donald Hart
  • Publication number: 20120163331
    Abstract: Techniques are provided for selecting channels for a wider bandwidth operation mode of a wireless network, such as wireless network that operates in accordance with the IEEE 802.11n amendment. Alignments of so-called primary and secondary channels are selected to mitigate interference. Interfering sources, such as other transceivers or external interferers, or the energy from their transmissions, are identified and channels are selected. The selected channels are analyzed to determine whether primary-secondary channel assignments for the selected channels are feasible.
    Type: Application
    Filed: March 6, 2012
    Publication date: June 28, 2012
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Douglas Chan, Brian Donald Hart, Bretton Douglas
  • Patent number: 8155482
    Abstract: Techniques are provided for selecting channels for a wider bandwidth operation mode of a wireless network, such as wireless network that operates in accordance with the IEEE 802.11n amendment. Alignments of so-called primary and secondary channels are selected to mitigate interference. Interfering sources, such as other transceivers or external interferers, or the energy from their transmissions, are identified and channels are selected. The selected channels are analyzed to determine whether primary-secondary channel assignments for the selected channels are feasible.
    Type: Grant
    Filed: July 1, 2008
    Date of Patent: April 10, 2012
    Assignee: Cisco Technology, Inc.
    Inventors: Douglas Chan, Brian Donald Hart, Bretton Douglas
  • Patent number: 8023482
    Abstract: A dynamic rate limiting mechanism for wireless mesh networks. In particular implementations, a method comprising monitoring one or more clients associated with a wireless mesh network and the respective hop counts of the clients to a root mesh node of the wireless mesh network; determining, responsive to one or more events, a client data rate for one or more clients of the wireless mesh network based on the number of current clients and the respective hop counts of the current clients; and applying the client data rate to the wireless mesh network.
    Type: Grant
    Filed: March 15, 2007
    Date of Patent: September 20, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Xiaohong Gong, Bretton Lee Douglas, Robert B. O'Hara, Jr., Brian Donald Hart
  • Patent number: 7983667
    Abstract: In one embodiment, a method for generating a radio-frequency coverage map. The method includes receiving coverage map data comprising a plurality of locations within a region, and an identification of a location in the plurality of locations corresponding to a radio transceiver, wherein the locations within the region are represented by at least corresponding x- and y-terms of a Cartesian coordinate system. The method further includes receiving calibration data comprising a plurality of observed signal strength values at corresponding ones of the plurality of locations, converting the x- and y-terms of the locations of the coverage map data to corresponding first and second warped coordinate terms of a warped coordinate system, and computing, using linear interpolation and the first and second warped coordinate terms, predicted received signal strength values at one or more locations in the coverage map based on the calibration data.
    Type: Grant
    Filed: October 5, 2006
    Date of Patent: July 19, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Brian Donald Hart, Robert J. Friday, Milind Paranjpe
  • Patent number: 7978725
    Abstract: Methods, apparatuses and systems directed to facilitating load balancing and bandwidth allocation in wireless mesh networks. Generally, according to one implementation of the present invention, routing nodes implement a contention-based media access mechanism and self-allocate bandwidth within a wireless mesh network by dynamically modifying one or more contention-based transmission control parameters. The routing nodes determine a hop count and adjust one or more contention parameters based at least in part on the hop count.
    Type: Grant
    Filed: March 6, 2006
    Date of Patent: July 12, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Xiaohong Gong, Brian Donald Hart, Bretton Lee Douglas
  • Patent number: 7948991
    Abstract: In one embodiment, a method includes scheduling acknowledgements from a plurality of receivers in a wireless network, transmitting an acknowledgement schedule to the receivers, broadcasting or multicasting data to the receivers, processing acknowledgements received from receivers, and retransmitting at least a portion of the data to one or more of the receivers if an acknowledgement is not received from the one or more receivers. An apparatus for broadcasting or multicasting data in a wireless network is also disclosed.
    Type: Grant
    Filed: September 16, 2008
    Date of Patent: May 24, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Brian Donald Hart, Lu Qian
  • Patent number: 7944886
    Abstract: A wireless access point selection system. In particular implementations, a method includes receiving a notification that identifies a wireless access point that detects radar on an operating channel and identifies the operating channel; updating neighbor lists of one or more neighboring wireless access points to remove the wireless access point from the neighbor list, where the neighbor list comprises neighbor wireless access points, corresponding operating channels, and corresponding enable indications, where each enable indication indicates if a channel availability check is required before performing active scanning; and transmitting the updated neighbor list to the neighboring wireless access points. In one implementation, a system provides a DFS enable indication to wireless clients so they can know whether a channel availability check is required prior to transmitting.
    Type: Grant
    Filed: August 21, 2007
    Date of Patent: May 17, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: David S. Stephenson, Robert B. O'Hara, Jr., Brian Donald Hart, Christopher Meil
  • Publication number: 20110110293
    Abstract: In one embodiment, an apparatus includes a receiver configured for receiving a response message from a tracked device in a wireless network, the response message transmitted in response to a provoking message having an identifier of the tracked device in a transmitter address field, and a processor for measuring at least one location related parameter, extracting the identifier of the tracked device from the response message and identifying the response message as a location tracking message based on information in the response message. A field of the response message includes the identifier of the tracked device copied from the provoking message and the transmitter address is not provided in another field of the response message. An apparatus for location tracking is also disclosed.
    Type: Application
    Filed: November 12, 2009
    Publication date: May 12, 2011
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Brian Donald Hart, Allan Thomson, Visshwanth Reddy