Patents by Inventor Brian D. Hart
Brian D. 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).
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Patent number: 9807813Abstract: In response to receiving a probe request from a mobile client, an access point determines whether it should suppress a probe response. The access point receives a probe request from a wireless client device, and prepares a probe response to respond to the probe request. The access point determines whether the wireless client device is likely to associate with the wireless access point. Responsive to a determination that the wireless client device is unlikely to associate with the wireless access point, the access point suppresses the transmission of the probe response.Type: GrantFiled: April 15, 2015Date of Patent: October 31, 2017Assignee: Cisco Technology, Inc.Inventors: Brian D. Hart, John Matthew Swartz, Joshua Suhr, Matthew A. Silverman, Tak Ming Pang
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Publication number: 20170206421Abstract: Systems, methods, and computer program products to perform an operation comprising receiving, from a video monitoring system, a count of people detected at a first location, wherein the video monitoring system comprises a camera configured to capture video of the first location, receiving a count of wireless devices detected in a second location, and applying a first correction factor to the count of wireless devices detected at the second location to determine a number of people present in the second location, wherein the first correction factor is based on the count of people detected by the video monitoring system and a count of wireless devices in the first location.Type: ApplicationFiled: January 15, 2016Publication date: July 20, 2017Inventors: Santosh G. PANDEY, Anshul TYAGI, Brian D. HART, Andrew F. MYLES
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Patent number: 9706514Abstract: Techniques are presented herein for improving location determination of a wireless device in environments where there can be multipath issues. A wireless device having a plurality of antennas receives a wireless transmission from a target device whose location is to be determined. Channel state information data is generated based on reception of the transmission at the plurality of antenna. The channel state information data is separated or partitioned into subcarrier group specific data for each of a plurality of groups of subcarriers within a bandwidth of the received transmission. Location probability data is computed for each of the plurality of groups of subcarriers from the subcarrier group specific data for respective ones of the plurality of groups of subcarriers. The location probability data for the plurality of groups of subcarriers is combined to produce aggregate location probability data, from which a location of the target device is determined.Type: GrantFiled: December 2, 2014Date of Patent: July 11, 2017Assignee: Cisco Technology, Inc.Inventors: Matthew A. Silverman, Paul J. Stager, Brian D. Hart
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Patent number: 9668149Abstract: A system and method are provided for performing stomp-and-restart techniques in distributed MU-MIMO system. A plurality of radio head devices are provided that are configured to be deployed separated from each other in a coverage region of interest of a wireless network. A central processor subsystem is provided that is in communication with the plurality of radio head devices. The central processor subsystem configured to perform several operations based on downconverted samples received from the plurality of radio head devices.Type: GrantFiled: May 25, 2016Date of Patent: May 30, 2017Assignee: Cisco Technology, Inc.Inventors: Paul J. Stager, Matthew A. Silverman, Brian D. Hart, David Kloper
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Publication number: 20170150522Abstract: A pair of Clear Channel Assessment (CCA) rules are presented that protect an initiator's transmission at the responder, and the responder's transmission at the initiator, using additional fields transmitted in a preamble (header) of a Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) or in a Media Access Control (MAC) header, if unencrypted and robustly modulated. These techniques enable more parallel/simultaneous transmissions between devices that might otherwise interfere with each other, subject to ensuring an adequate Signal-to-Interface and-Noise Ratio (SINR) for the initiator's transmission at the responder and ensuring an adequate SINR for the responder's transmission at the initiator.Type: ApplicationFiled: February 9, 2017Publication date: May 25, 2017Inventor: Brian D. Hart
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Publication number: 20170135131Abstract: A third device stores a receive signal strength of a received response data unit transmitted by a second device in response to reception by the second device of a first data unit transmitted by a first device, obtains a clear channel access parameter included in a header of a second data unit transmitted by the first device to the second device. The clear channel access parameter is based on a sum of a transmit power used by the first device to transmit the second data unit to the second device and a receive signal strength of the response data unit at the first device. The third device determines a transmit power to be used by the third device to send a transmission to the fourth device based on transmission exchanges between devices in a particular service set.Type: ApplicationFiled: May 10, 2016Publication date: May 11, 2017Inventors: Brian D. Hart, David Kloper, Pooya Monajemi, Matthew A. Silverman
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Patent number: 9648615Abstract: A plurality of time slots are allocated during which a location procedure is performed for one or more target wireless devices. Select ones of a plurality of wireless access points at different positions are assigned to each time slot such that multiple wireless access points assigned to a given time slot are sufficiently separated. In addition, wireless access points are assigned to a corresponding one of a plurality of groups for each time slot such that wireless access points assigned to a group tune to a channel used by a wireless access point in the group that transmits one or more frames that are intended to provoke one or more response frames from the one or more wireless devices.Type: GrantFiled: December 2, 2014Date of Patent: May 9, 2017Assignee: Cisco Technology, Inc.Inventors: Shaunak Joshi, Paul J. Stager, Brian D. Hart, Santosh Pandey, Matthew A. Silverman
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Publication number: 20170127407Abstract: A method is provided in which a first wireless access point selects two or more of a plurality of client devices based on similarity of receive signal strength and carrier frequency offset with respect to the first wireless access point, and sends a downlink multi-user multiple-input multiple-output (MIMO) transmission to the two or more client devices. The downlink multi-user MIMO transmission is configured to solicit acknowledgments from the two or more client devices. The acknowledgments are received at a plurality of antennas of the first wireless access point from the two or more client devices. Uplink multi-user MIMO processing of the acknowledgments is performed from the two or more of the plurality of client devices to recover the acknowledgments respectively from each of the two or more client devices.Type: ApplicationFiled: January 17, 2017Publication date: May 4, 2017Inventors: Brian D. Hart, Matthew A. Silverman, Paul J. Stager, David Kloper
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Patent number: 9629119Abstract: Techniques are presented herein to coordinate ranging exchanges between base stations in order to enable any number of wireless devices in the vicinity of the base stations to obtain signals associated with ranging exchanges between base stations, time-of-departure report messages transmitted by the base stations to each other and time-of-arrival report messages transmitted by the base stations to each other, for use in computing the location of the wireless devices. Based on the multi-channel time-of-arrivals computed for the wireless device with respect to each base station, the multi-channel time-of-arrivals contained in the time-of-arrival report messages transmitted between base stations and the known locations of the base stations, a physical location is computed for the wireless device.Type: GrantFiled: August 27, 2015Date of Patent: April 18, 2017Assignee: Cisco Technology, Inc.Inventor: Brian D. Hart
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Patent number: 9629181Abstract: A pair of Clear Channel Assessment (CCA) rules are presented that protect an initiator's transmission at the responder, and the responder's transmission at the initiator, using additional fields transmitted in a preamble (header) of a Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) or in a Media Access Control (MAC) header, if unencrypted and robustly modulated. These techniques enable more parallel/simultaneous transmissions between devices that might otherwise interfere with each other, subject to ensuring an adequate Signal-to-Interference and-Noise Ratio (SINR) for the initiator's transmission at the responder and ensuring an adequate SINR for the responder's transmission at the initiator.Type: GrantFiled: March 13, 2015Date of Patent: April 18, 2017Assignee: Cisco Technology, Inc.Inventor: Brian D. Hart
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Patent number: 9584278Abstract: In accordance with an embodiment, a method is provided in which a first wireless access point sends a downlink multi-user multiple-input multiple-output (MIMO) transmission to a plurality of client devices. The downlink multi-user MIMO transmission is configured to solicit acknowledgments from two or more of the plurality of client devices. The acknowledgments are received at a plurality of antennas of the first wireless access point from the two or more of the plurality of client devices. Uplink multi-user MIMO processing of the acknowledgments is performed from the two or more of the plurality of client devices to recover the acknowledgments respectively from each of the two or more of the plurality of client devices.Type: GrantFiled: July 10, 2015Date of Patent: February 28, 2017Assignee: Cisco Technology, Inc.Inventors: Brian D. Hart, Matthew A. Silverman, Paul J. Stager, David Kloper
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Patent number: 9551775Abstract: A computing entity, such as a server, obtains a first, second, and third set of measurements based on wireless transmissions between one or more beacon devices, a wireless client device, and one or more wireless access points in a wireless network. The first set of measurements is associated with wireless transmissions from the beacon device(s) received at the wireless access points. The second set of measurements is associated with wireless transmissions between the wireless client device and the wireless access points. The third set of measurements is associated with wireless transmissions from beacon devices received at the wireless client device. An estimated location of the wireless client device is generated based on the first set of measurement data, the second set of measurement data, and the third set of measurement data.Type: GrantFiled: September 4, 2014Date of Patent: January 24, 2017Assignee: Cisco Technology, Inc.Inventors: Raghuram Rangarajan, Brian D. Hart
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Publication number: 20170012752Abstract: In accordance with an embodiment, a method is provided in which a first wireless access point sends a downlink multi-user multiple-input multiple-output (MIMO) transmission to a plurality of client devices. The downlink multi-user MIMO transmission is configured to solicit acknowledgments from two or more of the plurality of client devices. The acknowledgments are received at a plurality of antennas of the first wireless access point from the two or more of the plurality of client devices. Uplink multi-user MIMO processing of the acknowledgments is performed from the two or more of the plurality of client devices to recover the acknowledgments respectively from each of the two or more of the plurality of client devices.Type: ApplicationFiled: July 10, 2015Publication date: January 12, 2017Inventors: Brian D. Hart, Matthew A. Silverman, Paul J. Stager, David Kloper
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Publication number: 20160309537Abstract: In response to receiving a probe request from a mobile client, an access point determines whether it should suppress a probe response. The access point receives a probe request from a wireless client device, and prepares a probe response to respond to the probe request. The access point determines whether the wireless client device is likely to associate with the wireless access point. Responsive to a determination that the wireless client device is unlikely to associate with the wireless access point, the access point suppresses the transmission of the probe response.Type: ApplicationFiled: April 15, 2015Publication date: October 20, 2016Inventors: Brian D. Hart, John Matthew Swartz, Joshua Suhr, Matthew A. Silverman, Tak Ming Pang
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Publication number: 20160249342Abstract: 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: ApplicationFiled: April 29, 2016Publication date: August 25, 2016Inventor: Brian D. Hart
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Patent number: 9408036Abstract: Wireless transmissions from beacon devices are received at a plurality of receiver devices. The wireless transmissions comprise packets that carry information used for location-based services for mobile wireless devices. Content of one or more fields of the beacon packets received by one or more of the plurality of receiver devices is obtained. Measurement data associated with the transmissions received at the plurality of receiver devices is generated. Locations of the respective beacon devices are computed from the measurement data obtained by the plurality of receiver devices. Information identifying detected beacon devices and their locations are stored to maintain a location history of beacon devices over time locations. Changes from information contained in the location history are detected based on the locations computed for respective beacon devices from the measurement data and content of one or more fields of detected beacon packets.Type: GrantFiled: May 15, 2014Date of Patent: August 2, 2016Assignee: Cisco Technology, Inc.Inventors: Brian D. Hart, Raghuram Rangarajan, Sujai Hajela, Gregory H. Yamanishi, Gracia Wang, Allen J. Huotari
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Patent number: 9363048Abstract: 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: GrantFiled: September 19, 2013Date of Patent: June 7, 2016Assignee: Cisco Technology, Inc.Inventor: Brian D. Hart
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Publication number: 20160157225Abstract: A plurality of time slots are allocated during which a location procedure is performed for one or more target wireless devices. Select ones of a plurality of wireless access points at different positions are assigned to each time slot such that multiple wireless access points assigned to a given time slot are sufficiently separated. In addition, wireless access points are assigned to a corresponding one of a plurality of groups for each time slot such that wireless access points assigned to a group tune to a channel used by a wireless access point in the group that transmits one or more frames that are intended to provoke one or more response frames from the one or more wireless devices.Type: ApplicationFiled: December 2, 2014Publication date: June 2, 2016Inventors: Shaunak Joshi, Paul J. Stager, Brian D. Hart, Santosh Pandey, Matthew A. Silverman
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Publication number: 20160157201Abstract: Techniques are presented herein for improving location determination of a wireless device in environments where there can be multipath issues. A wireless device having a plurality of antennas receives a wireless transmission from a target device whose location is to be determined. Channel state information data is generated based on reception of the transmission at the plurality of antenna. The channel state information data is separated or partitioned into subcarrier group specific data for each of a plurality of groups of subcarriers within a bandwidth of the received transmission. Location probability data is computed for each of the plurality of groups of subcarriers from the subcarrier group specific data for respective ones of the plurality of groups of subcarriers. The location probability data for the plurality of groups of subcarriers is combined to produce aggregate location probability data, from which a location of the target device is determined.Type: ApplicationFiled: December 2, 2014Publication date: June 2, 2016Inventors: Matthew A. Silverman, Paul J. Stager, Brian D. Hart
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Publication number: 20160069978Abstract: A computing entity, such as a server, obtains a first, second, and third set of measurements based on wireless transmissions between one or more beacon devices, a wireless client device, and one or more wireless access points in a wireless network. The first set of measurements is associated with wireless transmissions from the beacon device(s) received at the wireless access points. The second set of measurements is associated with wireless transmissions between the wireless client device and the wireless access points. The third set of measurements is associated with wireless transmissions from beacon devices received at the wireless client device. An estimated location of the wireless client device is generated based on the first set of measurement data, the second set of measurement data, and the third set of measurement data.Type: ApplicationFiled: September 4, 2014Publication date: March 10, 2016Inventors: Raghuram Rangarajan, Brian D. Hart