Radio Frequency Identification Reader and Method of Operating the Same

• US 20080129461A1
• Filed: 12/03/2007
• Published: 06/05/2008
• Est. Priority Date: 12/01/2006
• Status: Abandoned Application

• Current Assignee: Xterprise Incorporated (SML Group Corp.)
• Original Assignee: Xterprise Incorporated (SML Group Corp.)
• Inventors: Abraham, Thomas C.
• Application Number:
  US11/949,653
• Publication Number:
  US 20080129461A1
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals

Abstract

A radio frequency identification (RFID) reader, system and method of operating the same. In one embodiment, the RFID reader includes a transmitter/receiver configured to detect a signal representing an RFID tag and a processor configured to compare a delta index from the signal to a threshold to determine when the RFID tag is moving. In another aspect, the present invention provides a method of operating an RFID tag including detecting a signal representing an RFID tag and comparing a delta index from the signal to a threshold to determine when the RFID tag is moving.

Claims

1. A radio frequency identification (RFID) reader, comprising:

a transmitter/receiver configured to detect a signal representing an RFID tag; and

a processor configured to compare a delta index from said signal to a threshold to determine when said RFID tag is moving.

2. The RFID reader as recited in claim 1 wherein said transmitter/receiver is configured to transmit a carrier signal and said signal represents a returned, modulated carrier signal from said RFID tag.

3. The RFID reader as recited in claim 1 wherein said RFID reader comprises an antenna, coupled to said transmitter/receiver, configured to receive said signal.

4. The RFID reader as recited in claim 1 wherein said signal is within a lobe of said RFID reader.

5. The RFID reader as recited in claim 1 wherein said signal is within a lobe of said RFID reader depending on a frequency and power levels employed by said RFID reader.

6. The RFID reader as recited in claim 1 wherein said processor is configured to compare a derivative of said delta index from said signal to said threshold to determine when said RFID tag is moving.

7. The RFID reader as recited in claim 1 wherein said delta index is selected from the group consisting of:

a received signal strength indication,

reads per second, and

time differential of arrival.

8. The RFID reader as recited in claim 1 wherein said delta index provides a low-high-low response or a high-low-high response.

9. The RFID reader as recited in claim 1 wherein said threshold is a pre-selected fixed threshold.

10. The RFID reader as recited in claim 1 wherein said threshold is dynamically selected in real time.

11. A method of operating a radio frequency identification (RFID) reader, comprising:

detecting a signal representing an RFID tag; and

comparing a delta index from said signal to a threshold to determine when said RFID tag is moving.

12. The method as recited in claim 11 further comprising transmitting a carrier signal and said signal represents a returned, modulated carrier signal from said RFID tag.

13. The method as recited in claim 11 wherein said signal is within a lobe of said RFID reader depending on a frequency and power levels employed by said RFID reader.

14. The method as recited in claim 11 wherein said comparing includes comparing a derivative of said delta index from said signal to said threshold to determine when said RFID tag is moving.

15. The method as recited in claim 11 wherein said delta index is selected from the group consisting of:

a received signal strength indication,

reads per second, and

time differential of arrival.

16. A radio frequency identification (RFID) system, comprising:

an RFID tag; and

an RFID reader, including;

an antenna,

a transmitter/receiver, coupled to said antenna, configured to transmit a carrier signal and detect a signal representing a returned, modulated carrier signal from said RFID tag, and

a processor configured to compare a delta index from said signal to a threshold to determine when said RFID tag is moving.

17. The RFID system as recited in claim 16 wherein said signal is within a lobe of said RFID reader depending on a frequency and power levels employed by said RFID reader.

18. The RFID system as recited in claim 16 wherein said processor is configured to compare a derivative of said delta index from said signal to said threshold to determine when said RFID tag is moving.

19. The RFID system as recited in claim 16 wherein said delta index is selected from the group consisting of:

a received signal strength indication,

reads per second, and

time differential of arrival.

20. The RFID system as recited in claim 16 wherein said delta index provides a low-high-low response or a high-low-high response.