Patents by Inventor Bretton Douglas

Bretton Douglas 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: 20090168712
    Abstract: A search algorithm to find a globally optimal radio plan for a wireless network, including assignments of frequency and transmission power to multiple access points. Two different evaluation metrics are used in order to provide an optimal solution in a reasonable time period. Frequency searches are performed using a special rapid evaluation metric. Transmission powers are selected using a more refined metric that estimates data throughput. The search results are deterministic and execution time is also substantially deterministic.
    Type: Application
    Filed: January 27, 2009
    Publication date: July 2, 2009
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Bretton Douglas, Timothy Olson
  • Publication number: 20090067403
    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: July 1, 2008
    Publication date: March 12, 2009
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Douglas Chan, Brian Donald Hart, Bretton Douglas
  • Patent number: 7502617
    Abstract: A search algorithm to find a globally optimal radio plan for a wireless network, including assignments of frequency and transmission power to multiple access points. Two different evaluation metrics are used in order to provide an optimal solution in a reasonable time period. Frequency searches are performed using a special rapid evaluation metric. Transmission powers are selected using a more refined metric that estimates data throughput. The search results are deterministic and execution time is also substantially deterministic.
    Type: Grant
    Filed: September 2, 2004
    Date of Patent: March 10, 2009
    Assignee: Cisco Technology, Inc.
    Inventors: Bretton Douglas, Timothy Olson
  • Patent number: 7468951
    Abstract: A method for evaluating number of additional admissible calls for use in call admission control includes tracking a percentage of channel busy time and transmission time of downlink and uplink voice packets, receiving a call admission request, and calculating the number of admissible calls. The number of admissible calls is calculated based on a channel bandwidth requirement determined from the percentage of channel busy time and a voice packet queuing requirement determined from the transmission time of downlink and uplink voice packets. The call admission request is approved if the number of admissible calls is greater than one and rejected if the number of admissible calls is less than one.
    Type: Grant
    Filed: February 2, 2005
    Date of Patent: December 23, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Lu Qian, Bretton Douglas, David Sheldon Stephenson, Sandeep Jay Shetty, Rajneesh Kumar, Wenfeng Huang
  • Publication number: 20080232256
    Abstract: In an example embodiment, a number of contending nodes and colliding nodes for a plurality of links of a network is determined. The capacity of each of the plurality of links is determined. A sum of the traffic demand of each of the plurality of links divided the throughput of each of the plurality of links is used to form a cost function for the network. One, or more, of a group consisting of a plurality of frequency assignments, a plurality of transmit powers, and a plurality of clear channel assessment (CCA) values is searched to obtain a global minimum for the cost function. The frequency assignments, transmit powers, and/or CCA values providing the global minimum for the cost function are selected.
    Type: Application
    Filed: March 21, 2007
    Publication date: September 25, 2008
    Inventors: Bretton Douglas, Brian Hart
  • 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: 7352718
    Abstract: Multiple Input Multiple Output (MIMO) technology in conjunction with the IEEE 802.11 standard enables simultaneous communication of data packets to or from multiple users in the same frequency. Spatial divisional multiple access (SDMA) is thus provided. In this way, system capacity can be increased to an extent that depends on available antenna resources and the multipath characteristics of the communication channel. Doubling or quadrupling of network throughput can be achieved.
    Type: Grant
    Filed: July 22, 2003
    Date of Patent: April 1, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Eldad Perahia, Bretton Douglas, David Pignatelli, David Stephenson
  • Patent number: 7352688
    Abstract: A specialized preamble is provided to facilitate matrix channel estimation of a MIMO channel. In a particular implementation, a channel training preamble provided by the IEEE 802.11a standard is modified to facilitate MIMO channel estimation.
    Type: Grant
    Filed: December 31, 2002
    Date of Patent: April 1, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Eldad Perahia, Bretton Douglas, David Pignatelli
  • Publication number: 20070281714
    Abstract: Determining the location of a radio tag or client station of a wireless network, and the location of coverage holes by receiving from a plurality of wireless stations of the wireless network path loss information of the path loss of one or more location frames received at the respective wireless stations. The location frames transmitted by the radio tag or client station having a pre-defined frame structure. The radio tags and client stations use a common infrastructure for transmitting a location frame configured for radiolocation by path loss measurement. The common infrastructure includes a pre-defined protocol common for both radio tags and client stations for transmitting information for reception by the plurality of stations of the wireless network for radiolocation. The pre-defined protocol includes using the location frame having the pre-defined frame structure.
    Type: Application
    Filed: August 21, 2007
    Publication date: December 6, 2007
    Inventors: Bretton Douglas, Timothy Olson, David Halasz, John Deng, Arnold Bilstad, Sheausong Yang, Richard Rebo, Jonathan Leary, Daryl Kaiser
  • Patent number: 7301924
    Abstract: The MAC layer of a wireless communication standard is modified to facilitate MIMO (multiple input multiple output) processing and thereby increase capacity and/or spectral efficiency. In one implementation, the IEEE 802.11a standard is modified in this way. A contention free period (CFP) is divided between MIMO communications and non-MIMO communications. An access point may maintain a list of nodes operating in MIMO mode and nodes operating in non-MIMO mode.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: November 27, 2007
    Assignee: Cisco Technology, Inc.
    Inventors: Ozgur Gurbuz, David Pignatelli, David Stephenson, Eldad Perahia, Bretton Douglas, Ender Ayanoglu
  • 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: 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: 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: 20070082677
    Abstract: In a wireless LAN (WLAN), methods, apparatuses and systems directed to facilitating configuration of a wireless network is provided. According to one implementation of the present invention, sensors are used to collect data associated with locations and other properties of access points of the wireless network. The collected data can then be used to assist in automatically configuring one or more aspects of the wireless network. In some implementations, the collected data can be used to dynamically re-configure the wireless network in real time. According to another implementation of the present invention, location computation mechanisms are used to collect data associated with the location of one or more wireless clients, and the data is used to dynamically adjust one or more radio frequency (RF) coverage maps in real time. The revised RF coverage maps can then be used to re-configure one or more operational parameters of the wireless network.
    Type: Application
    Filed: October 11, 2005
    Publication date: April 12, 2007
    Applicant: Cisco Technology, Inc.
    Inventors: Brian Donald Hart, Timothy Olson, James Amos, David Theobold, Bretton Douglas
  • Patent number: 7197013
    Abstract: Systems and methods for evaluating wireless network quality. A metric provided by embodiments of the present invention relies on information that is relatively easy to collect, can be very efficiently computed, and yet provides a realistic estimate of likely wireless network performance. In one implementation, the input includes path loss data and access point transmitter power level and frequency settings. A capacity indicator is computed for each client and each access point. A data rate indicator is computed for each client location. The traffic load is computed for each access point. Based on these computed indicators, a bidirectional client throughput can be computed for each client and a combined metric can be determined for the network as a whole.
    Type: Grant
    Filed: March 1, 2004
    Date of Patent: March 27, 2007
    Assignee: Cisco Technology, Inc.
    Inventors: Bretton Douglas, Timothy Olson
  • Publication number: 20070049319
    Abstract: Described herein are a computer-implemented method of determining a power plan/frequency plan combination assigning transmit frequency channels and transmit powers for a plurality of managed access points (APs) of a wireless network. Also described herein is a carrier medium carrying computer readable code configured to cause one or more processors of a processing system to implement the computer implemented method of determining a power plan/frequency plan combination.
    Type: Application
    Filed: September 1, 2005
    Publication date: March 1, 2007
    Inventors: Brian Hart, Bretton Douglas, Lu Qian
  • Publication number: 20060227751
    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: Application
    Filed: April 8, 2005
    Publication date: October 12, 2006
    Inventors: David Theobold, Lu Qian, Bretton Douglas, Brian Hart
  • Publication number: 20060171314
    Abstract: A method for evaluating number of additional admissible calls for use in call admission control includes tracking a percentage of channel busy time and transmission time of downlink and uplink voice packets, receiving a call admission request, and calculating the number of admissible calls. The number of admissible calls is calculated based on a channel bandwidth requirement determined from the percentage of channel busy time and a voice packet queuing requirement determined from the transmission time of downlink and uplink voice packets. The call admission request is approved if the number of admissible calls is greater than one and rejected if the number of admissible calls is less than one.
    Type: Application
    Filed: February 2, 2005
    Publication date: August 3, 2006
    Applicant: CISCO TECHNOLOGY, INC.
    Inventors: Lu Qian, Bretton Douglas, David Stephenson, Sandeep Shetty, Rajneesh Kumar, Wenfeng Huang
  • Publication number: 20060104253
    Abstract: A method including wirelessly receiving a packet at a wireless station belonging to a cell of a wireless network, the network for communicating according to a wireless network standard, each transmitting station of the cell able to transmit a packet that includes cell identification information; and ascertaining at the physical layer level whether or not the received packet is from another station of the cell by ascertaining whether or not the received packet includes the cell identification information of the cell.
    Type: Application
    Filed: December 15, 2005
    Publication date: May 18, 2006
    Inventors: Bretton Douglas, Eldad Perahia
  • Publication number: 20060072524
    Abstract: A method and an apparatus in a first wireless station of a network transmitting to a second wireless station. The network uses multi-tone OFDM signals. The first station includes multiple antennas and a receive and a transmit signal path per antenna. Each receive signal path includes a discrete Fourier transformer determining the tones in a received signal, and each transmit signal path includes an inverse discrete Fourier transformer converting tones to a signal. The method includes determining channel estimates for each tone and each receive path while receiving from the second station, determining transmit weights to transmit to the second station, tone-by-tone weighting a signal for transmission to the second station to produce weighted tone sets for each transmit signal path, and transmitting the weighted tone sets. The first station is configured so that the weighting produces additive beamforming without the second station needing multiple antennas.
    Type: Application
    Filed: October 1, 2004
    Publication date: April 6, 2006
    Inventors: Eldad Perahia, Bretton Douglas, Brian Hart, Daniel Lyons