Patents by Inventor Kurt E. Sundstrom
Kurt E. Sundstrom 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: 10733395Abstract: Embodiments are directed to restricting access to Radio Frequency Identification (RFID) tag information based on location. Access to RFID tag information may be restricted at the reader level, at the requester level, and at the network level. When reader-level restrictions exist, devices may be prevented from inventorying tags and retrieving information from tags. When requester-level restrictions exist, a requester or device may be prevented from receiving tag information from inventoried tags or a network. When network-level restrictions exist, a network may discard or otherwise restrict tag information received from devices.Type: GrantFiled: February 8, 2019Date of Patent: August 4, 2020Assignee: Impinj, Inc.Inventors: Christopher J. Diorio, Scott A. Cooper, Kurt E. Sundstrom, Todd E. Humes, Alberto Pesavento
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Patent number: 10204245Abstract: Embodiments are directed to restricting access to Radio Frequency Identification (RFID) tag information based on location. Access to RFID tag information may be restricted at the reader level, at the requester level, and at the network level. When reader-level restrictions exist, devices may be prevented from inventorying tags and retrieving information from tags. When requester-level restrictions exist, a requester or device may be prevented from receiving tag information from inventoried tags or a network. When network-level restrictions exist, a network may discard or otherwise restrict tag information received from devices.Type: GrantFiled: April 5, 2018Date of Patent: February 12, 2019Assignee: Impinj, Inc.Inventors: Christopher J. Diorio, Scott A. Cooper, Kurt E. Sundstrom, Todd E. Humes, Alberto Pesavento
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Patent number: 9959435Abstract: Embodiments are directed to restricting access to Radio Frequency Identification (RFID) tag information based on location. Access to RFID tag information may be restricted at the reader level, at the requester level, and at the network level. When reader-level restrictions exist, devices may be prevented from inventorying tags and retrieving information from tags. When requester-level restrictions exist, a requester or device may be prevented from receiving tag information from inventoried tags or a network. When network-level restrictions exist, a network may discard or otherwise restrict tag information received from devices.Type: GrantFiled: November 23, 2016Date of Patent: May 1, 2018Assignee: IMPINJ, INC.Inventors: Christopher J. Diorio, Scott A. Cooper, Kurt E. Sundstrom, Todd E. Humes, Alberto Pesavento
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Patent number: 9031504Abstract: RFID tags, tag circuits, and methods are provided that reject at least in part the distortion caused to wireless signals by interference in the environment. When the received RF wave is converted into an unfiltered input (971), a filtered output (972) is generated that does not include an artifact feature deriving from the distortion. The filtered output is used instead of the unfiltered input, which results in tag operation as if there were less interference in the environment, or none at all.Type: GrantFiled: October 29, 2013Date of Patent: May 12, 2015Assignee: Impinj, Inc.Inventors: John D. Hyde, Kurt E. Sundstrom
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Patent number: 8600298Abstract: RFID tags, tag circuits, and methods are provided that reject at least in part the distortion caused to wireless signals by interference in the environment. When the received RF wave is converted into an unfiltered input (971), a filtered output (972) is generated that does not include an artifact feature deriving from the distortion. The filtered output is used instead of the unfiltered input, which results in tag operation as if there were less interference in the environment, or none at all.Type: GrantFiled: November 1, 2012Date of Patent: December 3, 2013Assignee: Impinj, Inc.Inventors: John D. Hyde, Kurt E. Sundstrom
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Patent number: 8570157Abstract: Radio frequency identification (RFID) tags are selected for inventorying using a combination of preselect and/or post select criteria. The selection commands can be for selecting according to a tag memory content, by invoking the mask address or by comparing other tag characteristics. Selection criteria can be determined locally at a modem block of a reader or provided to the modem block by higher layers of the reader. Tags meeting the selection criteria are reported to the higher layers for further actions. Some tags may be held while waiting for instructions from the higher layer block(s). The instructions may involve one or more access operations, which may be performed using a higher transmit power than other operations.Type: GrantFiled: March 2, 2012Date of Patent: October 29, 2013Assignee: Impinj, Inc.Inventors: Christopher J. Diorio, Kurt E. Sundstrom, Dan Bowman
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Patent number: 8390430Abstract: An RFID reader uses an adaptive filter to mitigate the effects of colored noise in tag reply signals. The adaptive filter may be a linear equalizer, a linear-predictive canceller, or a decision-feedback equalizer. The adaptive filter estimates the colored noise portion of the signal received from the tag and removes the noise estimate from the tag signal. The adaptive filter bases its noise estimate on the difference between a desired signal and a portion of the received signal. The reader uses reader-generated training data, a CW signal, and/or portions of the tag reply signal to adapt the filter.Type: GrantFiled: August 10, 2012Date of Patent: March 5, 2013Assignee: Impinj, Inc.Inventors: Kurt E. Sundstrom, Paul Dietrich, Christopher J. Diorio, Andrew Friefeld
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Patent number: 8391785Abstract: RFID tags, tag circuits, and methods are provided that reject at least in part the distortion caused to wireless signals by interference in the environment. When the received RF wave is converted into an unfiltered input (971), a filtered output (972) is generated that does not include an artifact feature deriving from the distortion. The filtered output is used instead of the unfiltered input, which results in tag operation as if there were less interference in the environment, or none at all.Type: GrantFiled: March 30, 2010Date of Patent: March 5, 2013Assignee: Impinj, Inc.Inventors: John D. Hyde, Kurt E. Sundstrom
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Patent number: 8350665Abstract: RFID tags are commanded to generate a pilot tone in their backscatter. When the backscattered pilot tone is received in the reader, the pilot tone is used to estimate the tag period/frequency. Then, the estimate is used to seed and lock a symbol timing recovery loop, which provides a detected signal to one or more correlators for detecting the tag preamble. A delayed version of the received tag signal is compared against a baseline signal threshold established from the received signal to detect the pilot tone.Type: GrantFiled: February 28, 2012Date of Patent: January 8, 2013Assignee: Impinj, Inc.Inventors: Kurt E. Sundstrom, Scott A. Cooper, Amir Sarajedini, Aanand Esterberg, Todd E. Humes, Christopher J. Diorio
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Patent number: 8325014Abstract: An RFID reader uses an adaptive filter to mitigate the effects of colored noise in tag reply signals. The adaptive filter may be a linear equalizer, a linear-predictive canceller, or a decision-feedback equalizer. The adaptive filter estimates the colored noise portion of the signal received from the tag and removes the noise estimate from the tag signal. The adaptive filter bases its noise estimate on the difference between a desired signal and a portion of the received signal. The reader uses reader-generated training data, a CW signal, and/or portions of the tag reply signal to adapt the filter.Type: GrantFiled: September 28, 2009Date of Patent: December 4, 2012Assignee: Impinj, Inc.Inventors: Kurt E. Sundstrom, Paul Dietrich, Christopher J. Diorio, Andrew Friefeld
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Patent number: 8258955Abstract: RFID tags, tag circuits, and methods are provided that reduce at least in part the distortion to received wireless signals, which is caused by interference in the environment. Two or more thresholds are used to digitize the received signal implemented by two or more demodulators. Multiple low pass and digital filters may be implemented with the demodulators, allowing removal of narrow pulses caused by the interference and reduction of beat tone amplitude.Type: GrantFiled: January 24, 2011Date of Patent: September 4, 2012Assignee: Impinj, Inc.Inventors: John D. Hyde, Kurt E. Sundstrom
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Patent number: 8243580Abstract: Briefly, in accordance with one embodiment of the invention, an orthogonal frequency division multiplexing system may provide a dynamically calculated cyclic extension, the length of which may be based at least in part on a delay spread due to an experienced environmental condition. The length of the cyclic extension may be calculated by determining a channel impulse response, and then computing the energy distribution of the channel impulse response. The length of the cyclic extension may then be set according to the energy distribution of the channel impulse response.Type: GrantFiled: July 14, 2008Date of Patent: August 14, 2012Assignee: Intel CorporationInventors: Kurt E. Sundstrom, Ernest Tsui, Richard B. Nicholls
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Patent number: 7917088Abstract: RFID tags, tag circuits, and methods are provided that reduce at least in part the distortion to received wireless signals, which is caused by interference in the environment. Two or more thresholds are used to digitize the received signal implemented by two or more demodulators. Multiple low pass and digital filters may be implemented with the demodulators, allowing removal of narrow pulses caused by the interference and reduction of beat tone amplitude.Type: GrantFiled: February 2, 2007Date of Patent: March 29, 2011Assignee: Impinj, Inc.Inventors: John D. Hyde, Kurt E. Sundstrom
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Patent number: 7830262Abstract: RFID reader systems, readers, components, software and methods are provided for inventorying RFID tags. In some embodiments, a population of RFID tags begins being inventoried using a first set of communication parameters, and then continues using a second set of communication parameters. This way, some RFID tags can be inventoried faster, without missing tags that require a longer time to read.Type: GrantFiled: June 4, 2008Date of Patent: November 9, 2010Assignee: Impinj, Inc.Inventors: Christopher J. Diorio, Aanand Esterberg, David Ord, Michael H. Thomas, Kurt E. Sundstrom
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Publication number: 20100182129Abstract: RFID tags, tag circuits, and methods are provided that reject at least in part the distortion caused to wireless signals by interference in the environment. When the received RF wave is converted into an unfiltered input (971), a filtered output (972) is generated that does not include an artifact feature deriving from the distortion. The filtered output is used instead of the unfiltered input, which results in tag operation as if there were less interference in the environment, or none at all.Type: ApplicationFiled: March 30, 2010Publication date: July 22, 2010Applicant: Impinj, Inc.Inventors: John D. Hyde, Kurt E. Sundstrom
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Patent number: 7472835Abstract: RFID system components, such as readers and tags, communicate by a reader transmitting waveforms that encode a calibration symbol and a divide ratio. Tags include a processor to determine a backscatter link period result by dividing a count value representing the calibration symbol by the divide ratio and adding an adjustment. Tags modulate a backscatter waveform that includes symbols using a link period determined from the result.Type: GrantFiled: April 25, 2005Date of Patent: January 6, 2009Assignee: Impinj, Inc.Inventors: Christopher J. Diorio, Kurt E. Sundstrom, Scott Anthony Cooper, Todd E. Humes
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Publication number: 20080273580Abstract: Briefly, in accordance with one embodiment of the invention, an orthogonal frequency division multiplexing system may provide a dynamically calculated cyclic extension, the length of which may be based at least in part on a delay spread due to an experienced environmental condition. The length of the cyclic extension may be calculated by determining a channel impulse response, and then computing the energy distribution of the channel impulse response. The length of the cyclic extension may then be set according to the energy distribution of the channel impulse response.Type: ApplicationFiled: July 14, 2008Publication date: November 6, 2008Inventors: Kurt E. Sundstrom, Ernest Tsui, Richard B. Nicholls
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Patent number: 7436308Abstract: Systems, software, devices, and methods are described for an RFID reader system to communicate with RFID tags. RF energy encountered in conjunction with using a selected channel is detected. The RF energy can be a signal from another RFID reader. The detected signal is used to adjust a waveform shaping parameter. RF waves can be transmitted from the reader to the RFID tags and RF waves can be backscattered from the RFID tags. At least some of the RF waves transmitted to or backscattered from the RFID tags have a waveform with a shape according to the adjusted waveform shaping parameter.Type: GrantFiled: April 25, 2006Date of Patent: October 14, 2008Assignee: Impinj, Inc.Inventors: Kurt E. Sundstrom, Christopher J. Diorio, Todd E. Humes, Paul Dietrich
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Patent number: 7432814Abstract: Systems, software, devices, and methods are described for an RFID reader system to communicate with RFID tags. RF energy detected in conjunction with using a selected channel is detected and used to adjust a waveform shaping parameter. The waveform shaping parameter can be additionally stored, and then reconstructed for later use in the same channel. Reconstruction can optionally be also from derived channel performance data. RF waves can be transmitted from the reader to the RFID tags and RF waves can be backscattered from the RFID tags. At least some of the RF waves transmitted to or backscattered from the RFID tags have a waveform with a shape according to the reconstructed waveform shaping parameter.Type: GrantFiled: April 25, 2006Date of Patent: October 7, 2008Assignee: Impinj, Inc.Inventors: Paul Dietrich, Christopher J. Diorio, Kurt E. Sundstrom, Todd E. Humes
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Patent number: 7417548Abstract: Systems, software, devices, and methods are described for an RFID reader system to communicate with RFID tags. RF energy encountered in conjunction with using a selected channel is detected. The RF energy can be a signal from an RFID tag. The detected signal is used to adjust a waveform shaping parameter. RF waves can be transmitted from the reader to the RFID tags and RF waves can be backscattered from the RFID tags. At least some of the RF waves transmitted to or backscattered from the RFID tags have a waveform with a shape according to the adjusted waveform shaping parameter.Type: GrantFiled: April 25, 2006Date of Patent: August 26, 2008Assignee: Impinj, Inc.Inventors: Gregory T. Kavounas, Christopher J. Diorio, Kurt E. Sundstrom, Todd E. Humes, Paul Dietrich