公开(公告)号：US12149938B2

公开(公告)日：2024-11-19

申请号：US16902071

申请日：2020-06-15

Applicant: Cisco Technology, Inc.

Inventor： Zhigang Gao ,  Huaiyi Wang

IPC: H04W12/106 ,  H04L1/00 ,  H04W12/122 ,  H04W12/79

Abstract: 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.

公开(公告)号：US20210075523A1

公开(公告)日：2021-03-11

申请号：US16564984

申请日：2019-09-09

Applicant: Cisco Technology, Inc.

Inventor： Huaiyi Wang ,  Zhigang Gao

IPC: H04B17/12 ,  H04L5/00 ,  H04W64/00

Abstract: 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.

公开(公告)号：US20150131593A1

公开(公告)日：2015-05-14

申请号：US14600300

申请日：2015-01-20

Applicant: Cisco Technology, Inc

Inventor： Paul J. Stager ,  Matthew A. Silverman ,  Zhigang Gao ,  John Blosco ,  Raghuram Rangarajan

IPC: H04W72/08 ,  H04L5/00 ,  H04W72/04

CPC classification number: H04W72/082 ,  H04L5/0073 ,  H04W24/02 ,  H04W72/0426 ,  H04W72/046 ,  H04W84/12 ,  H04W88/08

Abstract: In a wireless local area network, each of multiple access points, in a high density deployment, are configured to suppress co-channel interference. A first access point having a plurality of antennas beamforms a transmission to a wireless client device within a null-space or with the weakest singular eigenmodes of a wireless channel between the first access point and at least one co-channel second access point. Techniques are presented herein for situations in which any given access point has two or more co-channel access points. In addition, an access point may perform receive side suppression with respect to a transmission (made by a co-channel access point to one of its associated wireless client devices) that is received from that co-channel access point.

Abstract translation: 在无线局域网中，高密度部署中的多个接入点中的每一个被配置为抑制同信道干扰。 具有多个天线的第一接入点波束在零空间内或在第一接入点与至少一个同频道第二接入点之间的无线信道的最弱奇异本征模式中形成向无线客户端设备的传输。 本文给出了任何给定接入点具有两个或更多个同频道接入点的情况的技术。 此外，接入点可以针对从该同频道接入点接收到的传输（由与其相关联的无线客户端设备之一的同频道接入点进行的）进行接收侧抑制。

公开(公告)号：US20230198669A1

公开(公告)日：2023-06-22

申请号：US18171760

申请日：2023-02-21

Applicant: Cisco Technology, Inc.

Inventor： Brian Hart ,  Zhigang Gao

IPC: H04L1/00

CPC classification number: H04L1/0068

Abstract: 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.

公开(公告)号：US11368236B2

公开(公告)日：2022-06-21

申请号：US16562598

申请日：2019-09-06

Applicant: Cisco Technology Inc.

Inventor： Huaiyi Wang ,  Matthew Aaron Silverman ,  Zhigang Gao ,  Evgeny Yankevich

IPC: H04W48/16 ,  H04J11/00 ,  H04L5/00 ,  H04L25/03 ,  H04W56/00

Abstract: 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.

公开(公告)号：US10794983B1

公开(公告)日：2020-10-06

申请号：US16521860

申请日：2019-07-25

Applicant: Cisco Technology, Inc.

Inventor： Mukul Chandail ,  Khashayar Mirfakhraei ,  Matthew Aaron Silverman ,  Xu Zhang ,  Zhigang Gao ,  Paul Jeffrey Stager

IPC: H04W24/02 ,  G01S3/32 ,  G01S11/04 ,  G01S11/06 ,  H04W4/029 ,  H04W64/00 ,  G06N20/00 ,  G01S5/02

Abstract: 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.

公开(公告)号：US11057121B2

公开(公告)日：2021-07-06

申请号：US16564984

申请日：2019-09-09

Applicant: Cisco Technology, Inc.

Inventor： Huaiyi Wang ,  Zhigang Gao

IPC: H04B17/12 ,  H04W64/00 ,  H04L5/00 ,  H04W24/02 ,  H04B17/391

Abstract: 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.

公开(公告)号：US10362538B2

公开(公告)日：2019-07-23

申请号：US15663467

申请日：2017-07-28

Applicant: Cisco Technology, Inc.

Inventor： Zhigang Gao ,  Paul J. Stager ,  Fred J. Anderson

IPC: H04W52/02 ,  H04L27/26 ,  H04W72/04 ,  H04W16/14 ,  H04L5/00 ,  H04W76/28

Abstract: 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.

公开(公告)号：US09332557B2

公开(公告)日：2016-05-03

申请号：US14600300

申请日：2015-01-20

Applicant: Cisco Technology, Inc.

Inventor： Paul J. Stager ,  Matthew A. Silverman ,  Zhigang Gao ,  John Blosco ,  Raghuram Rangarajan

IPC: H04W4/00 ,  H04W72/08 ,  H04W24/02 ,  H04L5/00 ,  H04W72/04 ,  H04W84/12 ,  H04W88/08

CPC classification number: H04W72/082 ,  H04L5/0073 ,  H04W24/02 ,  H04W72/0426 ,  H04W72/046 ,  H04W84/12 ,  H04W88/08

Abstract: In a wireless local area network, each of multiple access points, in a high density deployment, are configured to suppress co-channel interference. A first access point having a plurality of antennas beamforms a transmission to a wireless client device within a null-space or with the weakest singular eigenmodes of a wireless channel between the first access point and at least one co-channel second access point. Techniques are presented herein for situations in which any given access point has two or more co-channel access points. In addition, an access point may perform receive side suppression with respect to a transmission (made by a co-channel access point to one of its associated wireless client devices) that is received from that co-channel access point.

Abstract translation: 在无线局域网中，高密度部署中的多个接入点中的每一个被配置为抑制同信道干扰。 具有多个天线的第一接入点波束在零空间内或在第一接入点与至少一个同频道第二接入点之间的无线信道的最弱奇异本征模式中形成向无线客户端设备的传输。 本文给出了任何给定接入点具有两个或更多个同频道接入点的情况的技术。 此外，接入点可以对从该同频道接入点接收到的传输（由与其相关联的无线客户端设备之一的同频道接入点进行的）进行接收侧抑制。

公开(公告)号：US20150085958A1

公开(公告)日：2015-03-26

申请号：US14037807

申请日：2013-09-26

Applicant: Cisco Technology, Inc.

Inventor： Zhigang Gao ,  Raghuram Rangarajan ,  David Kloper

IPC: H04L25/06

CPC classification number: H04L25/063

Abstract: Techniques are presented herein for distinguishing between the DC component of a real signal and DC energy of a received signal due to the radio receiver circuitry. Samples are obtained of a received signal derived from output of a receiver of a communication device. A mean of the samples is computed over a sample window comprising a predetermined number of samples. First and second thresholds are provided, the first threshold being greater than the second threshold. An absolute value of the mean is compared with respect to the first threshold and the second threshold as samples are obtained in the sample window. A selection is made between the first threshold and the second threshold for purposes of comparison with the absolute value of the mean to determine whether energy at DC is a true/real DC component of the received signal or is due to circuitry of the receiver.

Abstract translation: 这里给出了用于区分由无线电接收器电路引起的实际信号的DC分量和接收信号的DC能量之间的技术。 获得从通信设备的接收机的输出得到的接收信号的样本。 在包含预定数量的样本的样本窗口上计算样本的平均值。 提供第一和第二阈值，第一阈值大于第二阈值。 将平均值的绝对值相对于第一阈值和第二阈值进行比较，因为样本窗口中获取样本。 在第一阈值和第二阈值之间进行选择，以便与平均值的绝对值进行比较，以确定DC处的能量是否是接收信号的真实/真实DC分量，或者是由于接收机的电路。