ALEXANDRIA, Va., Oct. 21 -- United States Patent no. 12,444,841, issued on Oct. 14, was assigned to NXP B.V. (Eindhoven, Netherlands).
"NFC-based distance determination" was invented by Pouyan Ebrahimbabaie Varnosfaderani (Graz, Austria), Johannes Stahl (Graz, Austria) and Ulrich Andreas Muehlmann (Graz, Austria).
According to the abstract* released by the U.S. Patent & Trademark Office: "A device may include a data storage device storing a first look-up table that contains a plurality of distance mappings that each associate a value of a first signal feature with a distance value. An NFC reader is configured to communicate with an NFC tag includes: an antenna, a transmitter that is configured to use the antenna to transmit a radio freque...