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: 10568134Abstract: A third device stores a receive signal strength of a received response data unit transmitted by a second device after receiving a first data unit transmitted by a first device. The third 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 and detects transmission exchanges in each of a plurality of service sets to use as samples of overlapping service set activity. The third device determines a minimum 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. The third device determines whether to send a transmission to the fourth device based on the clear channel access parameter and minimum transmit power.Type: GrantFiled: July 17, 2018Date of Patent: February 18, 2020Assignee: Cisco Technology, Inc.Inventors: Brian D. Hart, David Kloper, Pooya Monajemi, Matthew A. Silverman
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Publication number: 20200029361Abstract: In a wireless local area network (WLAN) that includes one or more wireless access points capable of serving one or more wireless clients, presence of one or more instances of interference from a particular type of interferer is detected on at least one channel in an unlicensed frequency band. In response to detecting the interference, a radio resource management process is biased to continue operation of at least one of the one or more access points, or individual radios of a multi-radio access point, on the channel to make at least some use of the channel for one or more wireless clients.Type: ApplicationFiled: July 17, 2018Publication date: January 23, 2020Inventors: Vishal S. Desai, Brian D. Hart, David Kloper, Andrew Myles
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Publication number: 20200015220Abstract: Bypassing radar in wide Dynamic Frequency Selection (DFS) channels utilizing puncturing may be provided. A first client device may be classified as eligible for puncturing and a second client device may be classified as not eligible for puncturing. Next, it may be determined that a subchannel in a bandwidth range should not be used. Then, in response to determining that the subchannel in the bandwidth range should not be used, the first client device may be steered to a first subset of the bandwidth range and the second client device may be steered to a second subset of the bandwidth range. The second subset of the bandwidth range may be smaller than the first subset of the bandwidth range.Type: ApplicationFiled: July 8, 2019Publication date: January 9, 2020Applicant: Cisco Technology, Inc.Inventors: Benjamin Jacob Cizdziel, Brian D. Hart, Pooya Monajemi, David Kloper
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Patent number: 10433313Abstract: 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: April 29, 2016Date of Patent: October 1, 2019Assignee: Cisco Technology, Inc.Inventor: Brian D. Hart
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Publication number: 20190246368Abstract: Techniques are disclosed to synchronize wireless signal transmission by endpoints controlled by a central controller. For example, an example method of wireless communication includes receiving, at a first device, over a wired medium between the first device and a second device, a plurality of packets from the second device. Each of the plurality of packets comprises data representative of a portion of a signal corresponding to a wireless medium. The method further includes receiving, at the first device, from the second device over the wired medium a synchronization signal based on a common master clock at the second device. The method further includes synchronizing, at the first device, a local clock of the first device to the common master clock based on the synchronization signal. The method further includes reconstructing the signal corresponding to the wireless medium based on the plurality of packets and the synchronized local clock.Type: ApplicationFiled: April 18, 2019Publication date: August 8, 2019Inventors: Paul J. STAGER, David S. KLOPER, Brian D. HART, Matthew A. SILVERMAN
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Publication number: 20190245593Abstract: A wireless access point device wirelessly communicates with a plurality of wireless client devices. The wireless access point includes a central processor subsystem and a plurality of transceiver devices each including a plurality of antennas, and a plurality of radio transceivers, each of the plurality of transceiver devices configured for deployment throughout a coverage area, each transceiver device being connected to the central processor subsystem via a respective cable. The central processor subsystem distributes in-phase and quadrature baseband samples across the plurality of transceiver devices associated with traffic to be transmitted and received via the plurality of transceiver devices in one or more frequency bands so as to synthesize a wideband multiple-input multiple-output transmission channel and a wideband multiple-input multiple-output reception channel. The access point transmit and receive functions are “split” or partitioned across the plurality of transceivers devices.Type: ApplicationFiled: April 15, 2019Publication date: August 8, 2019Inventors: Brian D. Hart, Paul J. Stager, David Kloper, Jie Cheng Jiang
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Publication number: 20190238368Abstract: The embodiments herein use a factorization based technique for determining filter coefficients for a subset of the subcarriers in a wireless frequency band. Once the filter coefficients for the subset of the subcarriers are calculated, the network device uses these filter coefficients to identify the filter coefficients in a neighboring subcarrier. To do so, the network device uses pseudo-inverse iteration to convert the already calculated filter coefficients into filter coefficients for a neighboring subcarrier. The network device can repeat this process for the next set of neighboring subcarriers until all the filter coefficients have been calculated.Type: ApplicationFiled: April 8, 2019Publication date: August 1, 2019Inventors: Mithat C. DOGAN, Brian D. HART, Jiunming HUANG, Matthew A. SILVERMAN
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Patent number: 10367550Abstract: The present disclosure discloses that a device uses precoding to transmit independent data streams to existing users and additional independent data streams to one or more new users simultaneously. During a first transmission of a first one or more data streams that are precoded using a first precoding matrix, the device determines to transmit a second one or more data streams in a second transmission. Before the first transmission is complete, the device calculates a combined precoding matrix for precoding the first one or more data streams and the second one or more data streams. The device transmits the first one or more data streams in the first transmission and the second one or more data streams in the second transmission simultaneously using the combined precoding matrix.Type: GrantFiled: April 3, 2017Date of Patent: July 30, 2019Assignee: Cisco Technology, Inc.Inventors: David S. Kloper, Mithat C. Dogan, Matthew A. Silverman, Brian D. Hart, Jiunming Huang
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Publication number: 20190229951Abstract: Techniques are disclosed to reduce latency of processing for access points using a central controller. For example, an example method of wireless communication includes receiving, at an access point, a signal wirelessly. The method further includes filtering the signal using a first passband filter having a first bandwidth to generate a first filtered signal. The method further includes filtering the signal using a second passband filter having a second bandwidth to generate a second filtered signal, wherein the first bandwidth is less than the second bandwidth. The method further includes determining whether the signal includes a packet based on the first filtered signal and generating a control signal indicative of the determination. The method further includes transmitting the control signal and the second filtered signal to a central controller.Type: ApplicationFiled: April 1, 2019Publication date: July 25, 2019Inventors: Brian D. HART, David S. KLOPER, Jiunming HUANG, Glendon L. AKINS, III
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Patent number: 10326538Abstract: Embodiments herein describe calibrating a plurality of radio heads having a plurality of wireless antennas. In one embodiment, the plurality of radio heads communicate a calibration signal in a round robin fashion such that each of the radio heads communicates a respective calibration signal to the remaining radio heads. The received calibration signals are then used to calibrate the radio heads. In one embodiment, a controller coupled with the plurality of radio heads calibrates the radio heads. The calibrated radio heads then communicate to one or more client devices.Type: GrantFiled: April 5, 2017Date of Patent: June 18, 2019Assignee: Cisco Technology, Inc.Inventors: Mithat C. Dogan, Jiunming Huang, Brian D. Hart, Matthew A. Silverman
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Publication number: 20190173691Abstract: The present disclosure discloses a distributed system. The distributed system includes a plurality of radio heads and a plurality of controllers disposed in one or more chassis external to the plurality of radio heads. Each of the plurality of controllers includes a baseband unit (BBU), an uplink time-division multiplexing (TDM) switch and a downlink TDM switch. The uplink TDM switch and the downlink TDM switch forward data bits between a radio head and a BBU by using TDM cells which may reduce latency relative to using Ethernet frames.Type: ApplicationFiled: January 30, 2019Publication date: June 6, 2019Inventors: David S. KLOPER, Brian D. HART, Dipankar B. ACHARYA
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Patent number: 10312979Abstract: A wireless access point device wirelessly communicates with a plurality of wireless client devices. The wireless access point includes a central processor subsystem and a plurality of transceiver devices each including a plurality of antennas, and a plurality of radio transceivers, each of the plurality of transceiver devices configured for deployment throughout a coverage area, each transceiver device being connected to the central processor subsystem via a respective cable. The central processor subsystem distributes in-phase and quadrature baseband samples across the plurality of transceiver devices associated with traffic to be transmitted and received via the plurality of transceiver devices in one or more frequency bands so as to synthesize a wideband multiple-input multiple-output transmission channel and a wideband multiple-input multiple-output reception channel. The access point transmit and receive functions are “split” or partitioned across the plurality of transceivers devices.Type: GrantFiled: July 27, 2016Date of Patent: June 4, 2019Assignee: Cisco Technology, Inc.Inventors: Brian D. Hart, Paul J. Stager, David Kloper, Jie Cheng Jiang
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Patent number: 10306675Abstract: A central processor subsystem controls multiple transceivers. Each transceiver transmits protocol data units from antennas of that transceiver and produces receive waveforms from wirelessly received signals at the one or more antennas. A transmit waveform, including a frame addressed to one or more wireless client devices, is sent through a first transceiver to be transmitted wirelessly by the first transceiver on a frequency channel. A receive waveform, representative of the transmission by the first transceiver and wirelessly received at a second transceiver, is received from the second transceiver. While the transmit waveform is being sent to the first transceiver: a level of collision between the receive waveform and another transmission on the frequency channel is detected; and if the level of collision exceeds a threshold prior to an end of the receive waveform, the transmit waveform being sent to the first transceiver is modified to reduce the collision.Type: GrantFiled: May 3, 2017Date of Patent: May 28, 2019Assignee: Cisco Technology, Inc.Inventors: David Kloper, Brian D. Hart, Matthew A. Silverman, Paul J. Stager
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Publication number: 20190158157Abstract: A wireless device, such as an wireless access point, receives signals detected by a plurality of antennas of a wireless device to produce a plurality of antenna-specific receive signals potentially representing a wireless transmission received from each of one or a plurality of devices. A signal processing component of the wireless device, such as a modem, performs several operations on the antenna-specific receive signals, including building a first space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover a transmission from a first device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the first device, and building a second space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover a transmission from a second device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the second device.Type: ApplicationFiled: November 21, 2017Publication date: May 23, 2019Inventors: Xiaoli Ma, Hongyi Fu, Brian D. Hart, Matthew A. Silverman
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Patent number: 10285148Abstract: Techniques are disclosed to synchronize wireless signal transmission by endpoints controlled by a central controller. For example, an example method of wireless communication includes receiving, at a first device, over a wired medium between the first device and a second device, a plurality of packets from the second device. Each of the plurality of packets comprises data representative of a portion of a signal corresponding to a wireless medium. The method further includes receiving, at the first device, from the second device over the wired medium a synchronization signal based on a common master clock at the second device. The method further includes synchronizing, at the first device, a local clock of the first device to the common master clock based on the synchronization signal. The method further includes reconstructing the signal corresponding to the wireless medium based on the plurality of packets and the synchronized local clock.Type: GrantFiled: April 28, 2017Date of Patent: May 7, 2019Assignee: Cisco Technology, Inc.Inventors: Paul J. Stager, David S. Kloper, Brian D. Hart, Matthew A. Silverman
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Patent number: 10277293Abstract: A wireless device, such as an wireless access point, receives signals detected by a plurality of antennas of a wireless device to produce a plurality of antenna-specific receive signals potentially representing a wireless transmission received from each of one or a plurality of devices. A signal processing component of the wireless device, such as a modem, performs several operations on the antenna-specific receive signals, including building a first space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover a transmission from a first device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the first device, and building a second space-time equalizer to be applied to the plurality of antenna-specific receive signals to recover a transmission from a second device by both equalizing channel effects and canceling out effects associated with transmissions from devices other than the second device.Type: GrantFiled: November 21, 2017Date of Patent: April 30, 2019Assignee: Cisco Technology, Inc.Inventors: Xiaoli Ma, Hongyi Fu, Brian D. Hart, Matthew A. Silverman
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Patent number: 10277384Abstract: Embodiments herein describe using an intermediate distribution frame (IDF) which is connected between a central controller and a plurality radio heads which each include at least one antenna for wireless communication with a user device. Instead of running separate cables to each of the radio heads, a single cable can be used to connect the IDF to the central controller and then separate cables can be used to connect the IDF to the radio heads. If the IDF is disposed near the radio heads, the amount of cables can be reduced. Moreover, the IDF may recover a clock signal used by the central controller and forward that clock to the plurality of radio head in order to synchronize the radio heads to the central controller.Type: GrantFiled: April 4, 2017Date of Patent: April 30, 2019Assignee: Cisco Technology, Inc.Inventors: David S. Kloper, Brian D. Hart, Paul J. Stager
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Patent number: 10256997Abstract: The embodiments herein use a factorization based technique for determining filter coefficients for a subset of the subcarriers in a wireless frequency band. Once the filter coefficients for the subset of the subcarriers are calculated, the network device uses these filter coefficients to identify the filter coefficients in a neighboring subcarrier. To do so, the network device uses pseudo-inverse iteration to convert the already calculated filter coefficients into filter coefficients for a neighboring subcarrier. The network device can repeat this process for the next set of neighboring subcarriers until all the filter coefficients have been calculated.Type: GrantFiled: December 16, 2016Date of Patent: April 9, 2019Assignee: Cisco Technology, Inc.Inventors: Mithat C. Dogan, Brian D. Hart, Jiunming Huang, Matthew Silverman
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Patent number: 10250415Abstract: Techniques are disclosed to reduce latency of processing for access points using a central controller. For example, an example method of wireless communication includes receiving, at an access point, a signal wirelessly. The method further includes filtering the signal using a first passband filter having a first bandwidth to generate a first filtered signal. The method further includes filtering the signal using a second passband filter having a second bandwidth to generate a second filtered signal, wherein the first bandwidth is less than the second bandwidth. The method further includes determining whether the signal includes a packet based on the first filtered signal and generating a control signal indicative of the determination. The method further includes transmitting the control signal and the second filtered signal to a central controller.Type: GrantFiled: March 2, 2017Date of Patent: April 2, 2019Assignee: Cisco Technology, Inc.Inventors: Brian D. Hart, David S. Kloper, Jiunming Huang, Glendon L. Akins, III
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Patent number: 10218416Abstract: Embodiments herein describe a network device (e.g., an access point) that dynamically arranges multi-user (MU) multiple input multiple output (MIMO) compatible client devices into MU-MIMO groups. That is, the network device uses network metrics and historical data to change the assignment of client devices in the MU-MIMO groups which may improve MU-MIMO efficiency by reducing the amount of power that leaks between the clients devices in the group. In one embodiment, the AP identifies a MU-MIMO group based on a performance evaluation such as evaluating network metric or determining if the group is underutilized. The AP can replace the identified MU-MIMO group with a substitute MU-MIMO group where the substitute MU-MIMO group is selected based on historical data corresponding to the client devices assigned to the substitute MU-MIMO group.Type: GrantFiled: February 13, 2017Date of Patent: February 26, 2019Assignee: Cisco Technology, Inc.Inventors: Matthew A. Silverman, Paul J. Stager, David S. Kloper, Brian D. Hart, Qing Zhao