US 12,444,841 B2
NFC-based distance determination
Pouyan Ebrahimbabaie Varnosfaderani, Graz (AT); Johannes Stahl, Graz (AT); and Ulrich Andreas Muehlmann, Graz (AT)
Assigned to NXP B.V., Eindhoven (NL)
Filed by NXP B.V., Eindhoven (NL)
Filed on May 6, 2023, as Appl. No. 18/144,188.
Prior Publication US 2024/0372258 A1, Nov. 7, 2024
Int. Cl. H01Q 7/00 (2006.01); H01Q 1/22 (2006.01)
CPC H01Q 7/00 (2013.01) [H01Q 1/2208 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A system, comprising:
a data storage device configured to store a first look-up table that contains a plurality of distance mappings, where each distance mapping associates a value of a first signal feature with a distance value, wherein the first signal feature includes at least one of a phase-mean-phase (PMP) of the one or more response signals and a phase-circular-variance (PCV) of the one or more response signals; and
a near-field communications (NFC) reader configured to communicate with an NFC tag, the NFC reader including:
an antenna,
a transmitter electrically connected to the antenna, the transmitter being configured to use the antenna to transmit a radio frequency transmitted field,
a receiver electrically connected to the antenna, the receiver being configured to receive from the antenna one or more response signals in response to the radio frequency transmitted field transmitted by the transmitter, and
a signal processor configured to:
process the one or more response signals to determine a first value of the first signal feature of the one or more response signals,
access the first look-up table to determine a first distance mapping that associates the value of the first signal feature with a first distance, and
generate an output signal based upon the first distance.