US 12,294,966 B2
Methods, apparatus and device-readable mediums for detecting changes in distance between wireless devices
Dennis Sundman, Sollentuna (SE); Satyam Dwivedi, Solna (SE); and Miguel Lopez, Solna (SE)
Assigned to Telefonaktiebolaget LM Ericsson (Publ), Stockholm (SE)
Appl. No. 17/430,806
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
PCT Filed Feb. 21, 2019, PCT No. PCT/EP2019/054386
§ 371(c)(1), (2) Date Aug. 13, 2021,
PCT Pub. No. WO2020/169202, PCT Pub. Date Aug. 27, 2020.
Prior Publication US 2022/0167293 A1, May 26, 2022
Int. Cl. H04W 4/02 (2018.01); G01S 13/76 (2006.01); G01S 19/51 (2010.01); H04W 56/00 (2009.01)
CPC H04W 56/005 (2013.01) [G01S 13/765 (2013.01); G01S 19/51 (2013.01); H04W 4/023 (2013.01); H04W 56/006 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method of detecting changes in a distance between a first wireless device and a second wireless device, the method comprising:
determining a variation of a parameter over time, based on measurements of first timing signals transmitted between the first wireless device and the second wireless device, the variation of the parameter depending on the distance between the first wireless device and the second wireless device, and the variation of the parameter including periodic step transitions that are a result of relative clock drift between the first wireless device and the second wireless device;
based on the variation of the parameter, predicting a time at which one of the periodic step transitions is expected to occur;
determining a value of the parameter based on measurements of second timing signals transmitted between the first wireless device and the second wireless device, the second timing signals being transmitted subsequent to the first timing signals and close to the predicted time; and
responsive to determining that the determined value of the parameter differs from an expected value of the parameter, determining that the distance between the first wireless device and the second wireless device has changed.