Systems and methods to determine motion parameters using RFID tags

Patent metadata

Field	Value
Publication number	US-10650200-B2
Application number	US-201916405946-A
Country	US
Kind code	B2
Filing date	May 7, 2019
Priority date	Jun 5, 2008
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

Systems and methods to determine motion parameters of physical objects using radio frequency identification (RFID) tags attached to the objects. In one embodiment, a method implemented in a radio frequency identification (RFID) system includes determining a motion parameter of the RFID tag based on detecting a Doppler frequency shift in a radio frequency signal received from the RFID tag.

First claim

What is claimed is:

1. A reader, comprising:
a transceiver coupled with an antenna;
an oscillator to generate a signal;
a modulator coupled between the oscillator and the transceiver to modulate the signal transmitted via the antenna;
a modulation remover coupled with the transceiver to remove modulations from a reflected version of the signal received in the transceiver and generate a modulation-free version of the signal received in the transceiver;
a frequency detector coupled with the modulation remover to determine a Doppler frequency shift between the signal generated by the oscillator and the modulation-free version of the signal received in the transceiver; and
wherein the reader determines an identity of a device reflecting the signal transmitted via the antenna and a position of the device based on the Doppler frequency shift.

2. A method implemented in a reader, the method comprising:
generating, by an oscillator of the reader, a signal;
modulating, by a modulator coupled between the oscillator and a transceiver of the reader, the signal transmitted via an antenna coupled with the transceiver;
removing, by a modulation remover coupled with the transceiver, modulations from a reflected version of the signal received in the transceiver to generate a modulation-free version of the signal received in the transceiver;
determining, by a frequency detector coupled with the modulation remover, a Doppler frequency shift between the signal generated by the oscillator and the modulation-free version of the signal received in the transceiver; and
determining, by the reader, an identity of a device reflecting the signal transmitted via the antenna and a position of the device based on the Doppler frequency shift.

3. A system, comprising:
a plurality of devices in a field, each of the devices having a unique identification among the plurality of devices; and
a reader, including:
a transceiver coupled with an antenna;
an oscillator to generate a signal;
a modulator coupled between the oscillator and the transceiver to modulate the signal transmitted via the antenna;
a modulation remover coupled with the transceiver to remove modulations from a reflected version of the signal received in the transceiver and generate a modulation-free version of the signal received in the transceiver;
a frequency detector coupled with the modulation remover to determine a Doppler frequency shift between the signal generated by the oscillator and modulation-free version of the signal received in the transceiver; and
wherein the reader determines an identity of a device, among the plurality of devices, reflecting the signal transmitted via the antenna and a position of the device based on the Doppler frequency shift.

4. The system of claim 3 , wherein the identity of the device is determined based at least in part on the modulations in the reflected version of the signal received in the transceiver.

5. The system of claim 4 , wherein the modulations produced by the modulator on the signal transmitted via the antenna represent a command to request the device having the identity to reflect the signal.

6. The system of claim 4 , wherein the modulations are provided by the device in response to a communication from the reader.

7. The system of claim 6 , wherein the communication is made via the signal modulated by the modulator and transmitted by the transceiver via the antenna; and the modulations provided by the device encode identification data stored in the device.

Assignees

• Micron Technology Inc

Inventors

• Tuttle John R

Classifications

• G06K7/10019

  resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. (collision between the communication channels used by wireless communication devices, where the solution is not particularly adapted for RFIDs or the like, H04W74/08) · CPC title

• H04Q2213/13095

  PIN / Access code, authentication · CPC title

• G06K7/10316 Primary

  using at least one antenna particularly designed for interrogating the wireless record carriers (antennas in general H01Q1/22) · CPC title

• G06K7/0008

  General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer · CPC title

• G01S13/756

  using a signal generator for modifying the reflectivity of the reflector (G01S13/758 takes precedence) · CPC title