Patents by Inventor Zhigang Gao
Zhigang Gao 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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Publication number: 20240121511Abstract: An example method for camera processing includes detecting a first region of interest for image content captured with a primary camera, detecting a second region of interest for image content captured with a secondary camera, comparing the first region of interest and the second region of interest, determining a first lens position for a secondary camera lens of the secondary camera based on an autofocus process for the secondary camera, determining a second lens position for the secondary camera lens of the secondary camera based on a determined lens position for a primary camera lens of the primary camera, determining a lens position for the secondary camera lens based on the first lens position or the second lens position based at least in part on the comparison, and causing the secondary camera to capture images with the secondary camera lens at the determined lens position.Type: ApplicationFiled: April 28, 2021Publication date: April 11, 2024Inventors: Jintao Xu, Yaoyao Hou, Mingchen Gao, Xiaocheng Wang, Zhigang Tian
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Patent number: 11916670Abstract: Preamble puncturing configuration information is encoded in a pad field, and alternatively or additionally, in a Service Field, depending on a transmission bandwidth of a Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU). Some implementations also encode one or more parity bits in the pad field or Service field. The PPDU including the preamble puncturing configuration information encodes, in various embodiments, a request to send frame, a clear to send frame, a power save poll frame, or a contention free end frame.Type: GrantFiled: February 21, 2023Date of Patent: February 27, 2024Assignee: CISCO TECHNOLOGY, INC.Inventors: Brian Hart, Zhigang Gao
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Patent number: 11714154Abstract: Techniques for determining a location of a client device using recursive phase vector subspace estimation are described. One technique includes receiving a plurality of angle-of-arrival (AoA) measurements from a plurality of access points (APs). Each AoA measurement includes a plurality of entries for phase values measured from a signal received from a client device at the plurality of APs. At least one AoA measurement of the plurality of AoA measurements that includes at least one of: (i) one or more entries with missing phase values and (ii) one or more entries with erroneous phase values is identified, based on a recursive phase estimation. The plurality of AoA measurements are updated based on the identified at least one AoA measurement. The location of the client device is determined, based on the updated plurality of AoA measurements.Type: GrantFiled: May 5, 2020Date of Patent: August 1, 2023Assignee: Cisco Technology, Inc.Inventors: Zhigang Gao, Matthew A. Silverman, Fred J. Anderson, Huaiyi Wang
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Publication number: 20230198669Abstract: Preamble puncturing configuration information is encoded in a pad field, and alternatively or additionally, in a Service Field, depending on a transmission bandwidth of a Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU). Some implementations also encode one or more parity bits in the pad field or Service field. The PPDU including the preamble puncturing configuration information encodes, in various embodiments, a request to send frame, a clear to send frame, a power save poll frame, or a contention free end frame.Type: ApplicationFiled: February 21, 2023Publication date: June 22, 2023Inventors: Brian Hart, Zhigang Gao
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Patent number: 11621798Abstract: Preamble puncturing configuration information is encoded in a pad field, and alternatively or additionally, in a Service Field, depending on a transmission bandwidth of a Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU). Some implementations also encode one or more parity bits in the pad field or Service field. The PPDU including the preamble puncturing configuration information encodes, in various embodiments, a request to send frame, a clear to send frame, a power save poll frame, or a contention free end frame.Type: GrantFiled: July 30, 2021Date of Patent: April 4, 2023Assignee: CISCO TECHNOLOGY, INC.Inventors: Brian Hart, Zhigang Gao
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Patent number: 11460534Abstract: Embodiments herein describe performing AoA resolving to identify a plurality of AoAs corresponding to a multipath signal and then using AP voting to identify a location of the client device. AoA resolving enables an AP to identify the different angles at which a multipath signal reaches the AP. That is, due to reflections, a wireless signal transmitted by a single client device may reach the AP using multiple paths that each has their own AoA. The AP can perform AoA resolving to identify the AoAs for the different paths in a multipath signal. In one embodiment, the AoAs for two APs (or a subset of the APs) can be used to identify cross points or intersection points that represent candidate locations of the client device. A voting module can determine whether those cross points corresponds to AoAs identified by the remaining APs.Type: GrantFiled: January 21, 2020Date of Patent: October 4, 2022Assignee: Cisco Technology, Inc.Inventors: Zhigang Gao, Matthew A. Silverman, Paul J. Stager, Huaiyi Wang
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Publication number: 20220247515Abstract: Preamble puncturing configuration information is encoded in a pad field, and alternatively or additionally, in a Service Field, depending on a transmission bandwidth of a Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU). Some implementations also encode one or more parity bits in the pad field or Service field. The PPDU including the preamble puncturing configuration information encodes, in various embodiments, a request to send frame, a clear to send frame, a power save poll frame, or a contention free end frame.Type: ApplicationFiled: July 30, 2021Publication date: August 4, 2022Inventors: Brian Hart, Zhigang Gao
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Patent number: 11374704Abstract: Aspects described herein include a method comprising predicting, based on one or more transmission characteristics, error values for a sequence of bit positions used for modulating data within a packet. The method further comprises generating a bitmap that maps one or more payload bits and one or more padding bits of the packet to respective bit positions of the sequence. The one or more padding bits are preferentially mapped to respective bit positions having relatively greater error values. The method further comprises modulating the sequence according to the bitmap.Type: GrantFiled: May 7, 2020Date of Patent: June 28, 2022Assignee: Cisco Technology, Inc.Inventors: Huaiyi Wang, Brian D. Hart, Matthew A. Silverman, Zhigang Gao
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Patent number: 11368236Abstract: A wireless node in a wireless communication network. The wireless node includes one or more interfaces configured to receive wireless transmissions, a memory comprising instructions, and a hardware processor. The wireless node samples a received wireless transmission into a plurality of time-based subdivisions for each subdivision of the wireless transmission the wireless node determines a cross-correlation between the subdivision and a local syncword. The local syncword is constructed to correlate to any primary synchronization signal, PSS, of a plurality of PSSs defined for synchronization in the wireless network. The wireless node, based on the cross-correlation, determines whether one PSS of the plurality of PSSs is present in the subdivision of the wireless transmission.Type: GrantFiled: September 6, 2019Date of Patent: June 21, 2022Assignee: CISCO TECHNOLOGY, INC.Inventors: Huaiyi Wang, Matthew Aaron Silverman, Zhigang Gao, Evgeny Yankevich
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Publication number: 20210392497Abstract: Aspects described herein provide for hardening an RF signature by dynamically utilizing a sending device carrier frequency offset (CFO) as part of the RF signature. The CFO and the CFO varying pattern of wireless devices observed. A radio frequency signature at a sending device is paired to a frequency offset estimation algorithm at a receiving device, the final CFO estimation error may be bounded to a small range for various applications and communication protocols, and utilized to properly identify the sending device at the receiving device.Type: ApplicationFiled: June 15, 2020Publication date: December 16, 2021Inventors: Zhigang GAO, Huaiyi WANG
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Publication number: 20210349171Abstract: Techniques for determining a location of a client device using recursive phase vector subspace estimation are described. One technique includes receiving a plurality of angle-of-arrival (AoA) measurements from a plurality of access points (APs). Each AoA measurement includes a plurality of entries for phase values measured from a signal received from a client device at the plurality of APs. At least one AoA measurement of the plurality of AoA measurements that includes at least one of: (i) one or more entries with missing phase values and (ii) one or more entries with erroneous phase values is identified, based on a recursive phase estimation. The plurality of AoA measurements are updated based on the identified at least one AoA measurement. The location of the client device is determined, based on the updated plurality of AoA measurements.Type: ApplicationFiled: May 5, 2020Publication date: November 11, 2021Inventors: Zhigang GAO, Matthew A. SILVERMAN, Fred J. ANDERSON, Huaiyi WANG
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Publication number: 20210351879Abstract: Aspects described herein include a method comprising predicting, based on one or more transmission characteristics, error values for a sequence of bit positions used for modulating data within a packet. The method further comprises generating a bitmap that maps one or more payload bits and one or more padding bits of the packet to respective bit positions of the sequence. The one or more padding bits are preferentially mapped to respective bit positions having relatively greater error values. The method further comprises modulating the sequence according to the bitmap.Type: ApplicationFiled: May 7, 2020Publication date: November 11, 2021Inventors: Huaiyi WANG, Brian D. HART, Matthew A. SILVERMAN, Zhigang GAO
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Publication number: 20210223352Abstract: Embodiments herein describe performing AoA resolving to identify a plurality of AoAs corresponding to a multipath signal and then using AP voting to identify a location of the client device. AoA resolving enables an AP to identify the different angles at which a multipath signal reaches the AP. That is, due to reflections, a wireless signal transmitted by a single client device may reach the AP using multiple paths that each has their own AoA. The AP can perform AoA resolving to identify the AoAs for the different paths in a multipath signal. In one embodiment, the AoAs for two APs (or a subset of the APs) can be used to identify cross points or intersection points that represent candidate locations of the client device. A voting module can determine whether those cross points corresponds to AoAs identified by the remaining APs.Type: ApplicationFiled: January 21, 2020Publication date: July 22, 2021Inventors: Zhigang GAO, Matthew A. SILVERMAN, Paul J. STAGER, Huaiyi WANG
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Patent number: 11057121Abstract: In some embodiments, a method obtains raw data from one or more packets received over a wireless channel via an antenna. The raw data comprises raw amplitude values and raw phase values. Each raw amplitude value and raw phase value corresponds to a respective OFDM symbol and subcarrier of a respective packet. The method further comprises processing the raw data according to an interference mitigation process and using the resulting calibrated amplitude values and calibrated phase values to determine weighted phase values. Each weighted phase value corresponds to a respective subcarrier. The method determines a phase variance for the antenna based on comparing the plurality of weighted phase values across the plurality of subcarriers. The method determines whether the wireless channel experiences line-of-sight propagation or non-line-of-sight propagation based at least in part on the phase variance.Type: GrantFiled: September 9, 2019Date of Patent: July 6, 2021Assignee: CISCO TECHNOLOGY, INC.Inventors: Huaiyi Wang, Zhigang Gao
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Publication number: 20210075534Abstract: A wireless node in a wireless communication network. The wireless node includes one or more interfaces configured to receive wireless transmissions, a memory comprising instructions, and a hardware processor. The wireless node samples a received wireless transmission into a plurality of time-based subdivisions. for each subdivision of the wireless transmission the wireless node determines a cross-correlation between the subdivision and a local syncword. The local syncword is constructed to correlate to any primary synchronization signal, PSS, of a plurality of PSSs defined for synchronization in the wireless network. The wireless node, based on the cross-correlation, determines whether one PSS of the plurality of PSSs is present in the subdivision of the wireless transmission.Type: ApplicationFiled: September 6, 2019Publication date: March 11, 2021Inventors: Huaiyi Wang, Matthew Aaron Silverman, Zhigang Gao, Evgeny Yankevich
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Publication number: 20210075523Abstract: In some embodiments, a method obtains raw data from one or more packets received over a wireless channel via an antenna. The raw data comprises raw amplitude values and raw phase values. Each raw amplitude value and raw phase value corresponds to a respective OFDM symbol and subcarrier of a respective packet. The method further comprises processing the raw data according to an interference mitigation process and using the resulting calibrated amplitude values and calibrated phase values to determine weighted phase values. Each weighted phase value corresponds to a respective subcarrier. The method determines a phase variance for the antenna based on comparing the plurality of weighted phase values across the plurality of subcarriers. The method determines whether the wireless channel experiences line-of-sight propagation or non-line-of-sight propagation based at least in part on the phase variance.Type: ApplicationFiled: September 9, 2019Publication date: March 11, 2021Inventors: Huaiyi Wang, Zhigang Gao
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Patent number: 10794983Abstract: In one embodiment, a device obtains a machine learning model indicative of how to focus on particular location information from a plurality of radio frequency (RF) elements to provide an accurate location estimate of a wireless client based at least in part on angle-of-arrival information of the wireless client. When the device then obtains location information regarding the wireless client from the plurality of RF elements, it may apply the machine learning model to the location information regarding the wireless client to focus on particular location information of the location information from the plurality of RF elements. The device may then estimate a physical location of the wireless client based on focusing on the particular location information during a locationing computation.Type: GrantFiled: July 25, 2019Date of Patent: October 6, 2020Assignee: Cisco Technology, Inc.Inventors: Mukul Chandail, Khashayar Mirfakhraei, Matthew Aaron Silverman, Xu Zhang, Zhigang Gao, Paul Jeffrey Stager
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Patent number: 10524272Abstract: In one embodiment, a control device associated with a wireless network of a given location determines a reference quality of location readings between access points and client devices based on using substantially all of an available wireless communication bandwidth. The control device may then determine channel state information (CSI) between the client devices and access points for each orthogonal frequency-division multiple access (OFDMA) resource unit (RU), and selects a subset of RUs for allocation to each respective client device, based on the subset of RUs allocated to each respective client device i) surpassing a determined threshold of certain parameters of the CSI, while also ii) providing a minimum quality of a location reading based on using only the subset of RUs as compared to the reference quality of location readings. The control device may then allocate the selected subset of RUs to each respective client device for location-preserving OFDMA-signaling-based communication.Type: GrantFiled: January 9, 2018Date of Patent: December 31, 2019Assignee: Cisco Technology, Inc.Inventors: Matt Silverman, Zhigang Gao, Oscar Bejarano Chavez, John Matthew Swartz, Santosh Ghanshyam Pandey
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Patent number: 10362538Abstract: Techniques are disclosed for generating 802.11 packets that simulate an 802.11ba Wake-Up Radio (WUR) packet by wireless access points (APs) that implement pre-802.11ba standards. According to one embodiment disclosed herein, a predefined bit stream including a plurality of data bits is evaluated. A data bit of the plurality is mapped to one of a plurality of subcarriers. A symbol is encoded in a data payload of a network packet based on the mapping of the data bit to the subcarrier. The symbol simulates an on-off key (OOK)-modulated symbol in a WUR sequence. The network packet is transmitted to a client device.Type: GrantFiled: July 28, 2017Date of Patent: July 23, 2019Assignee: Cisco Technology, Inc.Inventors: Zhigang Gao, Paul J. Stager, Fred J. Anderson
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Publication number: 20190215842Abstract: In one embodiment, a control device associated with a wireless network of a given location determines a reference quality of location readings between access points and client devices based on using substantially all of an available wireless communication bandwidth. The control device may then determine channel state information (CSI) between the client devices and access points for each orthogonal frequency-division multiple access (OFDMA) resource unit (RU), and selects a subset of RUs for allocation to each respective client device, based on the subset of RUs allocated to each respective client device i) surpassing a determined threshold of certain parameters of the CSI, while also ii) providing a minimum quality of a location reading based on using only the subset of RUs as compared to the reference quality of location readings. The control device may then allocate the selected subset of RUs to each respective client device for location-preserving OFDMA-signaling-based communication.Type: ApplicationFiled: January 9, 2018Publication date: July 11, 2019Inventors: Matt Silverman, Zhigang Gao, Oscar Bejarano Chavez, John Matthew Swartz, Santosh Ghanshyam Pandey