Resistive and capacitive modulation in an electromagnetic transponder

• US 8,754,753 B2
• Filed: 11/03/2010
• Issued: 06/17/2014
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: Stmicroelectronics France (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Enguent, Jean-Pierre
• Primary Examiner(s): Nguyen, Nam V
• Application Number:
  US12/938,403
• Publication Number:
  US 20110063087A1
• Time in Patent Office: 1,322 Days
• Field of Search: 340/10.3, 340/10.1, 340/10.4, 340/572.1, 340/572.4, 235/451, 235/492, 235/384, 375/258, 375/261, 455/67.4, 455/63
• US Class Current: 340/10.3
• 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

Abstract

The selection of at least one back-modulation element of an electromagnetic transponder from among a plurality of resistive and/or capacitive modulation elements of the load of an oscillating circuit of the transponder, including selecting the modulation element(s) according to a binary message received from a read/write terminal.

Claims

1. A method of communicating with a transponder proximate to a terminal, the method comprising:

A) at a start of a communication session with the transponder, determining a communication configuration for the terminal, the communication configuration comprising particular modulation scheme to be used by the terminal for communicating with the transponder;

B) determining an indicator for the communication configuration, the indicator identifying a particular arrangement of circuit elements of the transponder to produce the particular modulation scheme for signals transmitted from the transponder; and

C) transmitting to the transponder the indicator for the communication configuration.

2. The method of claim 1, wherein the indicator is a portion of a frame transmitted by the terminal to the transponder.

3. The method of claim 2, wherein the frame is a frame according to ISO standard 14443.

4. The method of claim 3, wherein the frame is a REQB frame.

5. The method of claim 1, further comprising:

repeating the acts of determining the communication configuration, determining the indicator, and transmitting over a plurality of iterations to determine a first communication configuration to be used for a subsequent communication between the terminal and the transponder.

6. A method comprising:

receiving, at a terminal, a first communication from a transponder;

determining, based at least in part on an evaluation of the first communication, a communication configuration for the transponder;

transmitting to the transponder an identifier for the communication configuration; and

receiving from the transponder a second communication communicated according to the communication configuration.

7. The method of claim 6, wherein:

determining the communication configuration comprises determining a modulation scheme; and

receiving the second communication comprises receiving a communication communicated according to the modulation scheme.

8. The method of claim 7, wherein:

determining the communication configuration further comprises determining an arrangement of circuit elements of the transponder that would cause the transponder to communicate according to the modulation scheme; and

transmitting the identifier comprises transmitting an identifier for the arrangement.

9. The method of claim 8, wherein transmitting the identifier for the arrangement comprises transmitting one or more bits, wherein each bit of the one or more bits corresponds to a switch of the transponder and indicates a state of the corresponding switch.

10. The method of claim 6, wherein:

determining the communication configuration further comprises determining an arrangement of circuit elements of the transponder that would cause the transponder to communicate according to the communicate configuration; and

transmitting the identifier comprises transmitting an identifier for the arrangement.

11. The method of claim 10, wherein transmitting the identifier for the arrangement comprises transmitting one or more bits, wherein each bit of the one or more bits corresponds to a switch of the transponder and indicates a state of the corresponding switch.

12. The method of claim 6, further comprising:

determining, based at least in part on an evaluation of the second communication, a second communication configuration for the transponder;

transmitting to the transponder a second identifier for the second communication configuration; and

receiving from the transponder a third communication communicated according to the second communication configuration.

13. The method of claim 6, further comprising:

determining a quality of the second communication communicated according to the communication configuration;

testing at least one second communication configuration, wherein the evaluating comprises, for each second communication configuration of the at least one second communication configuration;

transmitting to the transponder an identifier for the second communication configuration;

receiving, at the terminal, a corresponding communication communicated according to the second communication configuration; and

determining a quality of the corresponding communication;

evaluating the quality of the second communication and the quality of each of the corresponding communications corresponding to the at least one second communication configuration;

selecting, from among the communication configuration and the at least one second communication configuration and based at least in part on a result of the evaluating, a selected communication configuration;

transmitting to the transponder an identifier for the selected communication configuration; and

communicating, between the terminal and the transponder, one or more communications according to the selected communication configuration.

14. At least one storage having encoded thereon executable instructions that, when executed by at least one processor, cause the at least one processor to carry out a method comprising:

receiving, at a terminal, a first communication from a transponder;

determining, based at least in part on an evaluation of the first communication, a communication configuration for the transponder;

transmitting to the transponder an identifier for the communication configuration; and

receiving from the transponder a second communication communicated according to the communication configuration.

15. The at least one storage of claim 14, wherein:

determining the communication configuration comprises determining a modulation scheme; and

receiving the second communication comprises receiving a communication communicated according to the modulation scheme.

16. The at least one storage of claim 15, wherein:

determining the communication configuration further comprises determining an arrangement of circuit elements of the transponder that would cause the transponder to communicate according to the modulation scheme; and

transmitting the identifier comprises transmitting an identifier for the arrangement.

17. The at least one storage of claim 16, wherein transmitting the identifier for the arrangement comprises transmitting one or more bits, wherein each bit of the one or more bits corresponds to a switch of the transponder and indicates a state of the corresponding switch.

18. The at least one storage of claim 14, wherein the method further comprises:

determining, based at least in part on an evaluation of the second communication, a second communication configuration for the transponder;

transmitting to the transponder a second identifier for the second communication configuration; and

receiving from the transponder a third communication communicated according to the second communication configuration.

19. The at least one storage of claim 14, wherein the method further comprises:

determining a quality of the second communication communicated according to the communication configuration;

testing at least one second communication configuration, wherein the evaluating comprises, for each second communication configuration of the at least one second communication configuration;

transmitting to the transponder an identifier for the second communication configuration;

receiving, at the terminal, a corresponding communication communicated according to the second communication configuration; and

determining a quality of the corresponding communication;

evaluating the quality of the second communication and the quality of each of the corresponding communications corresponding to the at least one second communication configuration;

selecting, from among the communication configuration and the at least one second communication configuration and based at least in part on a result of the evaluating, a selected communication configuration;

transmitting to the transponder an identifier for the selected communication configuration; and

communicating, between the terminal and the transponder, one or more communications according to the selected communication configuration.

20. An apparatus comprising:

at least one wireless communication circuit; and

a control circuit adapted to;

receive, via the at least one wireless communication circuit, a first communication from a transponder;

determine, based at least in part on an evaluation of the first communication, a communication configuration for the transponder;

transmit to the transponder, via the at least one wireless communication circuit, an identifier for the communication configuration; and

receive from the transponder, via the at least one wireless communication circuit, a second communication communicated according to the communication configuration.

21. The apparatus of claim 20, wherein the at least one wireless communication circuit comprises at least one antenna.

22. The apparatus of claim 20, wherein the control circuit is adapted to communicate via the at least one wireless communication circuit according to a near-field communication protocol.

23. The apparatus of claim 22, wherein the control circuit is adapted to communicate via the at least one wireless communication circuit according to ISO 14443.