US 11,714,154 B2
Using recursive phase vector subspace estimation to localize and track client devices
Zhigang Gao, Twinsburg, OH (US); Matthew A. Silverman, Shaker Heights, OH (US); Fred J. Anderson, Lakeville, OH (US); and Huaiyi Wang, North Royalton, OH (US)
Assigned to Cisco Technology, Inc., San Jose, CA (US)
Filed by Cisco Technology, Inc., San Jose, CA (US)
Filed on May 5, 2020, as Appl. No. 16/867,410.
Prior Publication US 2021/0349171 A1, Nov. 11, 2021
Int. Cl. G01S 3/14 (2006.01); G01S 3/74 (2006.01); G01S 5/02 (2010.01)
CPC G01S 3/143 (2013.01) [G01S 3/74 (2013.01); G01S 5/0284 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A computer-implemented method performed by an apparatus, the computer-implemented method comprising:
obtaining a plurality of phase vectors from a plurality of fixed access points (APs), each of the plurality of phase vectors comprising a plurality of entries for phase values measured from a signal received from a client device at the plurality of fixed APs;
identifying at least a first phase vector of the plurality of phase vectors that comprises at least one of: (i) one or more entries with missing phase values or (ii) one or more entries with erroneous phase values, based on performing a first recursive phase estimation using the plurality of phase vectors;
generating a first updated plurality of phase vectors based on removing, from the first phase vector, at least one of (i) the one or more entries with missing phase values or (ii) the one or more entries with erroneous phase values;
identifying at least a second phase vector of the plurality of phase vectors that comprises at least one of (i) one or more entries with missing phase values or (ii) one or more entries with erroneous phase values, based on performing a second recursive phase estimation using the first updated plurality of phase vectors;
generating a second updated plurality of phase vectors, based on the identified second phase vector; and
determining a location of the client device, based on the second updated plurality of phase vectors.