公开(公告)号：US20210351879A1

公开(公告)日：2021-11-11

申请号：US16869311

申请日：2020-05-07

Applicant: Cisco Technology, Inc.

Inventor： Huaiyi WANG ,  Brian D. HART ,  Matthew A. SILVERMAN ,  Zhigang GAO

IPC: H04L1/20 ,  H04L1/00

Abstract: 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.

公开(公告)号：US20210349171A1

公开(公告)日：2021-11-11

申请号：US16867410

申请日：2020-05-05

Applicant: Cisco Technology, Inc.

Inventor： Zhigang GAO ,  Matthew A. SILVERMAN ,  Fred J. ANDERSON ,  Huaiyi WANG

IPC: G01S3/14 ,  G01S5/02 ,  G01S3/74

Abstract: 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.

公开(公告)号：US20210392497A1

公开(公告)日：2021-12-16

申请号：US16902071

申请日：2020-06-15

Applicant: Cisco Technology, Inc.

Inventor： Zhigang GAO ,  Huaiyi WANG

IPC: H04W12/10 ,  H04W12/00 ,  H04L1/00 ,  H04W12/12

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：US20210223352A1

公开(公告)日：2021-07-22

申请号：US16748704

申请日：2020-01-21

Applicant: Cisco Technology, Inc.

Inventor： Zhigang GAO ,  Matthew A. SILVERMAN ,  Paul J. STAGER ,  Huaiyi WANG

IPC: G01S5/02 ,  G01S5/04

Abstract: 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.