RFID repeater for range extension in modulated backscatter systems

• US 8,988,197 B2
• Filed: 08/27/2009
• Issued: 03/24/2015
• Est. Priority Date: 09/03/2008
• Status: Expired due to Fees

• Current Assignee: CHECKPOINT SYSTEMS, INC. (CCL Industries Incorporated)
• Original Assignee: CHECKPOINT SYSTEMS, INC. (CCL Industries Incorporated)
• Inventors: Wild, Ben J., Madhow, Upamanyu, Ramchandran, Kannan
• Primary Examiner(s): Nguyen, Nam V
• Application Number:
  US12/548,993
• Publication Number:
  US 20100156610A1
• Time in Patent Office: 2,035 Days
• Field of Search: 340/10.34, 340 101- 105, 340/572.1, 340/572.4, 340/5.92, 340/573.3, 235/383, 235/385, 235/492, 342/42, 455/7, 455/41.2
• US Class Current: 340/10.4
• 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

Abstract

A backscatter tag system including a tag having tag circuitry and a reader for transmitting a command signal to the tag includes an energizer node for transmitting an energy signal to the tag to energize the tag and provide energy for operating the tag circuitry and for emitting a backscatter signal by the tag. The energizer node includes an energizer receiver for receiving the command signal from the reader to provide a received command signal and an energizer transmitter for transmitting the received command signal from the reader to the tag. The energizer node transmits both the energy signal and the received command signal to the tag. The energizer transmitter can transmit a sinusoidal signal, a frequency hopping signal, a spread spectrum signal, or a frequency shifted signal to the tag. The backscatter tag circuitry can include a processor.

Claims

1. A backscatter tag system, comprising:

a reader for transmitting signals, wherein the transmitted signals include a command signal and an energy signal;

at least one tag having a tag circuitry, wherein the at least one tag is a multimode tag configured to operate (1) in a closed loop mode when the at least one tag detects and demodulates the transmitted signals, or (2) in an open loop mode when the at least one tag fails to detect the transmitted signals within a predefined time period; and

an energizer node;

receiving the energy signal from the reader and transmitting the energy signal to the at least one tag; and

receiving the command signal from the reader, wherein the energizer node performs a predefined function based on content of the received command signal.

2. The backscatter tag system of claim 1, wherein the energizer node transmits a sinusoidal signal to the at least one tag.

3. The backscatter tag system of claim 1, wherein the energizer node transmits a frequency hopping signal to the at least one tag.

4. The backscatter tag system of claim 1, wherein the energizer node transmits a spread spectrum signal to the at least one tag.

5. The backscatter tag system of claim 1, wherein the energizer node transmits a frequency shifted signal to the at least one tag.

6. The backscatter tag system of claim 1, wherein the at least one tag operates in an open loop mode emitting a backscatter signal independently of the command signal from the reader.

7. The backscatter tag system of claim 1, wherein the at least one tag operates in a closed loop mode emitting a backscatter signal in accordance with the command signal from the reader.

8. The backscatter tag system of claim 7, wherein the at least one tag responds to the reader in accordance with a predetermined reader protocol.

9. The backscatter tag system of claim 1, wherein the energizer node comprises a battery.

10. The backscatter tag system of claim 1, including a plurality of backscatter signals further comprising deterministic intervals between the backscatter signals of the plurality of backscatter signals.

11. The backscatter tag system of claim 1, including a plurality of backscatter signals further comprising random intervals between the backscatter signals of the plurality of backscatter signals.

12. The backscatter tag system of claim 1, wherein the command signal from the reader is transmitted from the reader to a multimode tag by way of the energizer node.

13. The backscatter tag system of claim 12, wherein the command signal from the reader comprises a command for the multimode tag to change its frequency of operation.

14. The backscatter tag system of claim 1, further comprising a plurality of tags and a plurality of energizer nodes having respective energizer node timing wherein the reader synchronizes the timing of the energizer nodes of the plurality of energizer nodes in order to control interference of tags of the plurality of tags.

15. The backscatter tag system of claim 1, wherein the energizer node further comprises:

a processor for providing a retransmission of the received command signal at a different frequency band; and

an amplifier, coupled to said processor, for amplifying the retransmission of the command signal.

16. The backscatter tag system of claim 1, wherein the energizer node is configured to receive the command signal in a first frequency band and retransmit the received command signal in a second frequency band, the first frequency band and the second frequency band being different frequency bands.

17. The backscatter tag system of claim 1, wherein:

the at least one tag receives the transmitted signals in accordance with a predefined protocol when the at least one tag operates in the closed loop mode, and

the at least one tag receives the transmitted signals independent of a predefined protocol when the at least one tag operates in the open loop mode.

18. A method, comprising:

transmitting signals, from a reader, wherein the transmitted signals include a command signal and an energy signal;

providing an RFID tag, wherein the RFID tag is a multimode tag configured to operate (1) in a closed loop mode when the RFID tag detects and demodulates the transmitted signals, or (2) in an open loop mode when the RFID tag fails to detect the transmitted signals from the reader within a predefined time period;

receiving, at an energizer node, the energy signal, and transmitting the received energizer signal from the energizer node to the RFID tag to energize the RFID tag; and

receiving the command signal at the energizer node, wherein the energizer node performs a predefined function based on content of the received command signal.

19. The method of claim 18, wherein the energizer node transmits a sinusoidal signal to the RFID tag.

20. A backscatter tag system, comprising:

a reader for transmitting signals, wherein the transmitted signals include a command signal and an energy signal;

at least one tag having a tag circuitry, wherein the at least one tag is a multimode tag configured to operate in an open loop mode when the at least one tag detects the transmitted signals and determines that the transmitted signals do not exceed a predefined threshold for decoding the command signal; and

an energizer node;

receiving the energy signal from the reader and transmitting the energy signal to the at least one tag; and

receiving the command signal from the reader, wherein the energizer node performs a predefined function based on content of the received command signal.

21. The backscatter tag system of claim 20, wherein the energizer node transmits a sinusoidal signal to the at least one tag.

22. A method, comprising:

transmitting signals, from a reader, wherein the transmitted signals include a command signal and an energy signal;

providing an RFID tag, wherein the RFID tag is a multimode tag configured to operate in an open loop mode when the RFID tag detects the transmitted signals and determines that the transmitted signals do not exceed a predefined threshold for decoding the command signal;

receiving, at an energizer node, the energy signal, and transmitting the received energizer signal from the energizer node to the RFID tag to energize the RFID tag; and

receiving the command signal at the energizer node, wherein the energizer node performs a predefined function based on content of the received command signal.

23. The method of claim 22, wherein the energizer node transmits a sinusoidal signal to the RFID tag.