Method and apparatus to configure an RFID system to be adaptable to a plurality of environmental conditions

• US 7,026,935 B2
• Filed: 04/13/2004
• Issued: 04/11/2006
• Est. Priority Date: 11/10/2003
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Diorio, Christopher J., Sundstrom, Kurt E.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US10/824,049
• Publication Number:
  US 20050099269A1
• Time in Patent Office: 728 Days
• Field of Search: 340/568.1, 340/572.1, 340/572.2, 340/572.4, 340/539.11, 340/539.13, 340/539.21, 340/10.1, 340/10.3, 340/10.6, 340/825.49, 235/375, 235/384, 235/435
• US Class Current: 340/572.2
• 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

Abstract

An RFID integrated circuit includes a demodulator to receive a first signal, the first signal having been generated by an RFID reader responsive to detection of a first environmental condition. The RFID integrated circuit further includes a controller to set, based on the first signal, a modulation format for the RFID integrated circuit and to configure the RFID integrated circuit to modulate a backscatter signal according to the modulation format.

Claims

1. An RFID reader adapted to communicate with RFID tags, comprising:

an interface to receive an input at the RFID reader indicating at least one of a plurality of conditions pertaining to an environment of the reader, the conditions being one of a number of RFID tags in the environment, a number of other readers operating in the environment, and whether another reader operates at a frequency in a similar channel as the reader;

a controller to select one of a plurality of modulation formats based on the input; and

an antenna for communicating with the tags according to the selected format.

2. The RFID reader of claim 1, in which

a different one of the modulation formats is selected depending on whether or not the number of tags in the environment exceeds a threshold.

3. The RFID reader of claim 1, in which

a different one of the modulation formats is selected depending on whether or not the number of readers in the environment exceeds a threshold.

4. The RFID reader of claim 1, in which

a different one of the modulation formats is selected depending on whether or not another reader has a frequency in a similar channel as the reader.

5. The RFID reader of claim 1, in which

the selected modulation format corresponds to selecting at least one of a group of configuration parameters for the reader including a bit rate, cycles per symbol, subcarrier frequency, symbol assignment, and backscatter duration.

6. The RFID reader of claim 1, further comprising:

a demodulator, and

wherein the controller is adapted to configure the demodulator to demodulate a signal that is backscattered from at least one of the tags according to the selected format.

7. The RFID reader of claim 1, in which

the antenna is adapted to transmit to the tags a signal for configuring the tags to backscatter by modulating according to the selected format.

8. The RFID reader of claim 1, in which

configuring the tags includes causing the tags to select at least one of a group of configuration parameters including a bit rate, cycles per symbol, subcarrier frequency, symbol assignment, and backscatter duration.

9. The RFID reader of claim 1, in which

the plurality of modulation formats includes at least one of a FMØ

, a Manchester, a pulse width modulation (PWM), a frequency shift key (FSK), an amplitude shift key (ASK), and a phase shift key (PSK) modulation format.

10. The RFID reader of claim 1, in which

the interface is a user interface, and

the input is manually provided to the RFID reader by a user.

11. The RFID reader of claim 1, in which

the interface is a network interface to a further computer system, and

the input is received via a network from the further computer system.

12. A method for an RFID reader to communicate with a plurality of RFID tags comprising:

receiving an input indicating at least one of a plurality of conditions pertaining to an environment of the reader, the conditions being one of a number of the RFID tags in the environment, a number of other readers operating in the environment, and whether another reader operates at a frequency in a similar channel as the reader;

selecting one of a plurality of modulation formats responsive to the input; and

communicating with the tags using the selected modulation format.

13. The method of claim 12, in which

a different one of the modulation formats is selected depending on whether or not the number of tags in the environment exceeds a threshold.

14. The method of claim 12, in which

a different one of the modulation formats is selected depending on whether or not the number of readers in the environment exceeds a threshold.

15. The method of claim 12, in which

a different one of the modulation formats is selected depending on whether or not another reader has a frequency in a similar channel as the reader.

16. The method of claim 12, in which

the selected modulation format corresponds to selecting at least one of a group of configuration parameters for the reader including a bit rate, cycles per symbol, subcarrier frequency, symbol assignment, and backscatter duration.

17. The method of claim 12, further comprising:

configuring a demodulator of the reader to demodulate a signal that is backscattered from at least one of the tags according to the selected format.

18. The method of claim 12, further comprising:

configuring the tags to backscatter using the selected modulation format.

19. The method of claim 18, in which

configuring the tags includes causing the tags to select at least one of a group of configuration parameters including a bit rate, cycles per symbol, subcarrier frequency, symbol assignment, and backscatter duration.

20. The method of claim 12, in which

the plurality of modulation formats includes at least one of a FMØ

, a Manchester, a pulse width modulation (PWM), a frequency shift key (FSK), an amplitude shift key (ASK), and a phase shift key (PSK) modulation format.

21. The method of claim 12, in which

the input is manually inputted by a user in a user interface, and received via the interface.

22. The method of claim 12, in which

the input is inputted by a computer system in a network interface, and received via the interface.