Patents by Inventor Brian Hart

Brian 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: 7391368
    Abstract: In an example embodiment, a time of arrival circuit coupled to a wireless transceiver configured to determine a time of arrival of a wireless signal. The time of arrival circuit is operative to perform a coarse-scale frequency domain correlation of the actual samples with a predetermined ideal sample. The time of arrival circuit determines a maximum coarse correlation coefficient. The time delay circuit is operative to determine a plurality of fine correlation coefficients by interpolating around the peak coarse correlation coefficient. The time of arrival circuit determines a maximum correlation coefficient from the plurality of fine correlation coefficients and a time delay associated with the maximum correlation coefficient, the time of arrival is based on the time delay associated with the maximum correlation coefficient.
    Type: Grant
    Filed: March 6, 2007
    Date of Patent: June 24, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Zhigang Gao, Paul Stager, Bretton Douglas, Brian Hart, James Amos, Yoonill Lee
  • Patent number: 7359311
    Abstract: A method, apparatus, and carrier medium for determining channel state information (CSI) in an OFDM radio receiver. The receiver is for receiving packets of OFDM data as a result of OFDM data being transmitted. The method includes forming an estimate of the channels of the subcarriers for received OFDM data to provide frequency responses of the channels of the subcarriers, and forming a measure of quality (“channel state information,” “CSI”) for the channels of the subcarriers based on the relative strength of the frequency responses. The forming of the CSI does not require estimating the relative amount of noise or interference in each channel. The formed CSI is used in demodulating and decoding received OFDM data.
    Type: Grant
    Filed: April 18, 2003
    Date of Patent: April 15, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Milind D. Paranjpe, Brian Hart, David J. Pignatelli, Ender Ayanoglu, Eldad Perahia, Philip J. Ryan, Bretton Lee Douglas, Uri Parker
  • Patent number: 7340000
    Abstract: In an OFDM radio receiver for a wireless packet network, an apparatus to equalize a presently received OFDM signal containing subcarriers using an equalizing signal formed from the past symbols of subcarriers. The apparatus includes a subtractor to subtract the equalizing signal from the present signal, a DFT device to convert to subcarriers, a forward processor to correct the subcarriers for the channel and phase errors, a decision device to make decisions for the subcarriers, a reverse processor to corrupt the decision-based subcarriers' phase in the same manner as the forward processor corrects the subcarrier's phase, an inverse DFT device to form a time signal from the reverse processed subcarriers, and a feedback filter to generate the equalizing signal. The feedback filter's impulse response is directly calculated from an estimate of the channel response.
    Type: Grant
    Filed: August 13, 2004
    Date of Patent: March 4, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Brian Hart, John D. O'Sullivan
  • Publication number: 20080039119
    Abstract: A method and an apparatus for radiolocation using time differences of arrival. The method includes receiving transmit timestamps from a set of wireless stations of a wireless network. Each station transmits at least once. The transmit timestamp uses a local timestamping clock to indicate when a station transmitted a packet. The method further includes receiving sets of timestamped captured samples from each station that receives one of the transmitted packets. The times of arrival of each packet at each station are determined from the received sets of timestamped captured samples, and, the relative positions of the stations are determined from the determined times of arrival and the received transmit timestamps. The transmitting by the stations is in a round robin manner one station after the other, and several round robins may be used to mutually calibrate local clocks. Also an apparatus for inclusion in a station of a wireless network.
    Type: Application
    Filed: October 18, 2007
    Publication date: February 14, 2008
    Inventors: Jason Crawford, John O'Sullivan, Brian Hart
  • Patent number: 7315533
    Abstract: A method, apparatus, and carrier medium carrying instructions to assign frequency channels and transmit powers for a plurality of access points of a wireless network. The method includes, until there are no more access points to which to assign a transmit power and frequency channel, selecting a next current access point, determining for a set of at least one transmit power for a set of at least one frequency channel a measure of the quality of the sub-network formed by the current access point and all already-assigned access points an evaluation metric indicative of the quality of the sub-network, and assigning to the current access point the transmit power and frequency channel that minimizes the measure of the quality of the sub-network.
    Type: Grant
    Filed: April 8, 2005
    Date of Patent: January 1, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: David M. Theobold, Lu Qian, Bretton Lee Douglas, Brian Hart
  • Patent number: 7304969
    Abstract: A digital AGC system for burst operation, particularly suited for receiving packets in a wireless local area network. One embodiment includes a log detector that provides a signal strength measure, called the received signal strength indication (RSSI) over a wide dynamic range. The AGC system includes estimating the power in a received signal by averaging the log of the signal power. The Start of Packet detection avoids using the radio receiver's main analog to digital converters to preserve power.
    Type: Grant
    Filed: November 8, 2006
    Date of Patent: December 4, 2007
    Assignee: Cisco Technology, Inc.
    Inventors: Philip J. Ryan, Andrew R. Adams, John D. O'Sullivan, Uri Parker, Brian Hart, Grzegorz B. Zyner
  • Patent number: 7302269
    Abstract: A method and an apparatus for radiolocation using time differences of arrival. The method includes receiving transmit timestamps from a set of wireless stations of a wireless network. Each station transmits at least once. The transmit timestamp uses a local timestamping clock to indicate when a station transmitted a packet. The method further includes receiving sets of timestamped captured samples from each station that receives one of the transmitted packets. The times of arrival of each packet at each station are determined from the received sets of timestamped captured samples, and, the relative positions of the stations are determined from the determined times of arrival and the received transmit timestamps. The transmitting by the stations is in a round robin manner one station after the other, and several round robins may be used to mutually calibrate local clocks. Also an apparatus for inclusion in a station of a wireless network.
    Type: Grant
    Filed: March 18, 2004
    Date of Patent: November 27, 2007
    Assignee: Cisco Technology, Inc.
    Inventors: Jason R. Crawford, John D. O'Sullivan, Brian Hart
  • Publication number: 20070259292
    Abstract: A method of etching a semiconductor substrate. The method includes the steps of applying a photoresist etch mask layer to a device surface of the substrate. A select first area of the photoresist etch mask is masked, imaged and developed. A select second area of the photoresist etch mask layer is irradiated to assist in post etch stripping of the etch mask layer from the select second area. The substrate is etched to form fluid supply slots through a thickness of the substrate. At least the select second area of the etch mask layer is removed from the substrate, whereby mask layer residue formed from the select second area of the etch mask layer is significantly reduced.
    Type: Application
    Filed: July 19, 2007
    Publication date: November 8, 2007
    Inventors: John Krawczyk, James Mrvos, Girish Patil, Jason Vanderpool, Brian Hart, Christopher Money, Jeanne Singh, Karthik Vaideeswaran
  • Publication number: 20070230403
    Abstract: A method and an apparatus for detecting the start-of-packet in a wireless receiver operating in a packetized wireless network. One method embodiment includes calculating a plurality of start of packet (SOP) indicators, each for one or more of a plurality of receive chains in the receiver; determining one or more linear combinations of respective pluralities of the calculated SOP indicators to form one or more combined SOP indicators; comparing each of a plurality of SOP indicators or combined SOP indicators, including at least one of the combined SOP indicators to a respective threshold to form one or more respective SOP events; and, in the case there is more than one SOP event, determining a logic function of the SOP events to form a SOP decision event.
    Type: Application
    Filed: June 4, 2007
    Publication date: October 4, 2007
    Inventors: Bretton Douglas, Brian Hart, Fred Anderson, Paul Stager, Gregory Corsetto
  • Publication number: 20070229594
    Abstract: Micro-fluid ejection head structures, methods of making micro-fluid ejection head structures having improved operability, and methods for improving the durability of micro-fluid ejection head structures are provided. One such micro-fluid ejection head structure includes a micro-fluid ejection head having a substrate and nozzle plate assembly adhesively attached adjacent to a substrate support using a substrate adhesive. The nozzle plate is adhesively attached adjacent to the substrate with a nozzle plate adhesive. A thermally, UV or other cure mechanism encapsulant material is attached adjacent to the ejection head and substrate support. Each of the substrate adhesive, and the encapsulant material, after curing, have a Young's modulus of less than about 2000 MPa, a shear modulus at 25° C. of less than about 15 MPa, and a glass transition temperature of less than about 90° C.
    Type: Application
    Filed: November 3, 2006
    Publication date: October 4, 2007
    Applicant: LEXMARK INTERNATIONAL, INC.
    Inventors: David Graham, Brian Hart, Gary Holt, John Krawczyk, Sean Weaver, Mary Smoot
  • Publication number: 20070222820
    Abstract: A method of making a micro-fluid ejection head structure for a micro-fluid ejection device. The method includes applying a removable mandrel material to a semiconductor substrate wafer containing fluid ejection actuators on a device surface thereof. The mandrel material is shaped to provide fluid chamber and fluid channel locations on the substrate wafer. A micro machinable material is applied to the shaped mandrel and the device surface of the wafer to provide a nozzle plate and flow feature layer on the shaped mandrel and wafer. A plurality of nozzle holes are formed in the nozzle plate and flow feature layer. The shaped mandrel material is then removed from the device surface of the substrate wafer to provide fluid chambers and fluid channels in the nozzle plate and flow feature layer.
    Type: Application
    Filed: May 29, 2007
    Publication date: September 27, 2007
    Inventors: Johnathan Barnes, Craig Bertelsen, Brian Hart, Gary Williams, Sean Weaver, Girish Patil
  • Publication number: 20070216737
    Abstract: A micro-fluid jetting device and a method of ejecting fluid mixtures onto a substrate. The micro-fluid jetting device includes a housing containing a logic circuit and fluid reservoirs for at least two different fluids. A micro-fluid ejection head is attached to a first end of the housing. The ejection head is in electrical communication with the logic circuit and the fluid reservoirs. At least two channel members are provided for directing fluid from the reservoirs to a plurality of fluid ejection nozzles in a nozzle plate member. The ejection nozzles for each of the at least two different fluids are arranged in the nozzle plate member so that adjacent ejection nozzles are in flow communication with different fluids. A power source in electrical connection with the micro-fluid ejection head is provided in the housing for activating the micro-fluid ejection head for jetting the fluids therefrom.
    Type: Application
    Filed: March 17, 2006
    Publication date: September 20, 2007
    Inventor: Brian Hart
  • Publication number: 20070206503
    Abstract: Methods, apparatuses and systems directed to facilitating increased throughput in wireless mesh networks. Generally, according to one implementation of the present invention, routing nodes in a wireless mesh network combine metrics corresponding to the link and network layers to select a route to a root node in the wireless mesh network. In one implementation, for each neighbor, a given routing node computes a routing metric, which is based on the computed route cost and hop count, and selects a preferred neighbor as the parent routing node based on the best routing metric.
    Type: Application
    Filed: March 6, 2006
    Publication date: September 6, 2007
    Applicant: Cisco Technology, Inc.
    Inventors: Xiaohong Gong, Brian Hart, Bretton Douglas
  • Publication number: 20070206547
    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: Application
    Filed: March 6, 2006
    Publication date: September 6, 2007
    Applicant: Cisco Technology, Inc.
    Inventors: Xiaohong Gong, Brian Hart, Bretton Douglas
  • Publication number: 20070188376
    Abstract: A method for radar protection. The method includes recording energy events and calculating differences in recorded energy events to determine pulses. The method further includes sorting intervals between pulses into histogram bins, each bin representing a range of time intervals between two pulses, each pulse indicative of a radar frequency and limiting network traffic on a frequency based on a selected bin count.
    Type: Application
    Filed: April 19, 2007
    Publication date: August 16, 2007
    Inventors: David Theobold, Christopher Meil, Edward Wright, James Amos, Brian Hart, Jason Crawford, Philip O'Sullivan, Kevin Wong
  • Patent number: 7230566
    Abstract: A method for radar protection. The method includes recording energy events and calculating differences in recorded energy events to determine pulses. The method further includes sorting intervals between pulses into histogram bins, each bin representing a range of time intervals between two pulses, each pulse indicative of a radar frequency and limiting network traffic on a frequency based on a selected bin count.
    Type: Grant
    Filed: August 3, 2004
    Date of Patent: June 12, 2007
    Assignee: Cisco Technology, Inc.
    Inventors: David M. Theobold, Christopher G. Meil, Edward Frederick Wright, James A. Amos, Brian Hart, Jason R. Crawford, Philip O′Sullivan, Kevin C. H. Wong
  • Publication number: 20070129034
    Abstract: An apparatus, a carrier medium storing instructions to implement a method, and a method for controlling the gain of a radio receiver for receiving packets of information in a wireless network. The receiver is connected to an antenna subsystem and has receive signal path including a plurality of sections including a first section coupled to the antenna subsystem and a next section. Each section has an adjustable gain and is able to provide a measure of the signal strength at its output. The method includes waiting for a start of packet indication, providing a measure of the signal strength at the output of the first section and the next section, and adjusting the gains of the first and the next sections using the provided measured signal strengths. In one embodiment, the receive signal path includes a filter, the provided measure for the first section is before the filter, and the provided measure for the second section is after the filter.
    Type: Application
    Filed: February 7, 2007
    Publication date: June 7, 2007
    Inventors: Andrew Adams, Philip Ryan, Brian Hart
  • Patent number: 7212798
    Abstract: An apparatus, a carrier medium storing instructions to implement a method, and a method for controlling the gain of a radio receiver for receiving packets of information in a wireless network. The receiver is connected to an antenna subsystem and has receive signal path including a plurality of sections including a first section coupled to the antenna subsystem and a next section. Each section has an adjustable gain and is able to provide a measure of the signal strength at its output. The method includes waiting for a start of packet indication, providing a measure of the signal strength at the output of the first section and the next section, and adjusting the gains of the first and the next sections using the provided measured signal strengths. In one embodiment, the receive signal path includes a filter, the provided measure for the first section is before the filter, and the provided measure for the second section is after the filter.
    Type: Grant
    Filed: July 17, 2003
    Date of Patent: May 1, 2007
    Assignee: Cisco Technology, Inc.
    Inventors: Andrew R. Adams, Philip J. Ryan, Brian Hart
  • Publication number: 20070092015
    Abstract: A method and apparatus for estimating channel characteristics in a multicarrier wireless receiver such as an OFDM wireless receiver. The method includes determining a channel estimate for each of a set of subcarriers by receiving multicarrier data as a result of a wireless transmission of data that includes a known signal, wherein the determining uses a part of the received data that corresponds to the known signal. The method further includes smoothing the channel estimates according to a smoothing filter to form smoothed channel estimates. The smoothed channel estimate for a particular subcarrier includes a contribution from the channel estimates of one or more subcarriers nearby the particular subcarrier take advantage of correlation that may exist between the particular subcarrier's channel and the channels of the one or more nearby subcarriers.
    Type: Application
    Filed: December 1, 2006
    Publication date: April 26, 2007
    Inventors: Brian Hart, John O'Sullivan
  • Patent number: 7201281
    Abstract: A modular pusher system for use with articles of merchandise in a display includes pusher tracks and dividers, each of which include detachable sections so that these basic components can be used in pusher systems of different depths. Spring loaded pushers are mounted on the tracks, and both the tracks and the dividers can be snap fit into slots in front and rear extrusions that can be mounted on a shelf. The tracks and the dividers include notches and cut-out sections which define auxiliary latching mechanisms intermediate the ends thereof, which can be snapped into the rear extrusion when rear sections are detached.
    Type: Grant
    Filed: December 18, 2003
    Date of Patent: April 10, 2007
    Assignee: Imageworks Display and Marketing Group
    Inventor: Brian Hart Welker