Method and system of information exchange between an interrogator device and transponder devices that takes into account the level of ambient noise

• US 7,369,036 B1
• Filed: 11/07/2000
• Issued: 05/06/2008
• Est. Priority Date: 11/08/1999
• Status: Expired due to Fees

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Vacherand, Francois, Crochon, Elisabeth
• Primary Examiner(s): Zimmerman; Brian
• Assistant Examiner(s): NGUYEN, NAM V
• Application Number:
  US10/129,832
• Time in Patent Office: 2,737 Days
• Field of Search: 340/10.1, 340/10.2, 340/10.33, 340/3.51, 340/572.1, 340/825.08, 340/825.34, 340/825.49, 340/573.1, 340/573.4, 340 561- 563, 701/300, 342/42, 370/346, 395/750, 455/135
• US Class Current: 340/10.1
• 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: G06K 7/10039 interrogator driven, i.e. synchronous

Abstract

A method and apparatus of information exchange between an interrogator device and a plurality of transponder devices are disclosed. Each of the transponder devices is equipped with a different binary identification code and is located in the magnetic field of the interrogator device, consisting in modifying the duration of the signals and/or the waveform of the signals transmitted by each transponder device according to the ratio between the signal transmitted by the transponder device and the ambient electromagnetic noise.

Claims

1. A method comprising information exchange between an interrogator device (DI) and a plurality of transponder devices (E₁, E₂), each of which is equipped with a different binary identification code and is located in the magnetic field of the interrogator device, whereby the interrogator device transmits RF signals intended to interrogate the transponder devices on the presence of a bit or of a group of bits in their identification code and in which the transponder devices transmit a response signal indicating whether or not this bit or group of bits is present, characterized in that it consists, at the beginning of the interrogation sequence, of modifying the duration of the response signals and/or the form of the response signals (S_r) transmitted by each transponder device according to the ratio between the signal transmitted by the transponder device and the ambient electromagnetic noise, said method comprising:

a) determining the signal-to-noise ratio between the signal transmitted by the transponder device and the ambient noise;

b) determining, from this signal-to-noise ratio, a parameter relating to the duration of the response signal from the transponder device or a parameter relating to the waveform of the response signal from the transponder device;

c) integrating this/these parameter(s) in the interrogation signal transmitted by the interrogator device;

d) receiving the interrogation signal by the transponder device and recording this/these duration and/or form parameter(s); and

e) transmitting a response signal by the transponder device during the duration recorded in d) and/or according to the form recorded in d).

2. A method according to claim 1, which includes in determining the duration parameter and/or the waveform parameter at the beginning of the first transponder devices interrogation sequence.

3. A method according to claim 1, which includes in determining the duration parameter and/or the waveform parameter at the beginning of each transponder devices interrogation sequence.

4. A method according to claim 3, wherein each transponder device is capable of transmitting two different signals, whereby each of these signals has a different waveform.

5. A method according to claim 4, wherein the two response signals are transmitted over two different time slots.

6. A method according to claim 4, wherein the two response signals are transmitted during the same time slot.

7. A method according to claim 3, wherein the two response signals are transmitted during the same time slot.

8. A system comprising information exchange between an interrogator device (DI) and multiple transponder devices (E₁, E₂) located in the electromagnetic field of the interrogator device, whereby each of these interrogator and transponder device comprises means of transmitting/receiving signals (1-4, 6, 11-13) together with electronic means of sequencing (5, 14) and means of recording (10, 15), characterized in that each transponder device contains a timer (8) for recording a duration determined according to the ratio between the signal transmitted by the transponder device and the ambient electromagnetic noise, and for counting a transmission time during this duration, and/or at least one shift register (7) for recording a waveform determined according to the ratio between the transmitted signal and the ambient electromagnetic noise and reproducing this waveform each time a signal is transmitted, said system configured to:

a) determine the signal-to-noise ratio between the signal transmitted by the transponder device and the ambient noise;

b) determine, from this signal-to-noise ratio, a parameter relating to the duration of the response signal from the transponder device or a parameter relating to the waveform of the response signal from the transponder device;

c) integrate this/these parameter(s) in the interrogation signal transmitted by the interrogator device;

d) receive the interrogation signal by the transponder device and recording this/these duration and/or form parameter(s);

e) transmit a response signal by the transponder device during the duration recorded in d) and/or according to the form recorded in d).

9. A method of information exchange between an interrogator device (DI) and at least one transponder device (E₁, E₂) located in the magnetic field of the interrogator device, each transponder device is equipped with a different binary identification code, whereby the interrogator device transmits RF signals intended to interrogate each transponder device on the presence of a bit or of a group of bits in their identification code and in which the transponder devices transmit a response signal indicating whether or not this bit or group of bits is present, characterized in that it consists, at the beginning of the interrogation sequence, of modifying a duration of the response signals and/or a waveform of the response signals (S_r) transmitted by each transponder device according to the ratio between the signal transmitted by the transponder device and the ambient electromagnetic noise, said method comprising the following steps:

a) the interrogator device defines a parameter relative to the duration and/or the waveform of the response signals (S_r) of each transponder device from the analysis of the signal-to-noise ratio between the signal transmitted by the transponder device and the ambient noise;

b) the interrogator device transmits to each transponder device a control signal to start the identification sequence, said control signal including the parameter defined in step a);

c) on reception of said control signal, each transponder;

interprets said control signal, identifies said parameter, and stores said parameter; and

d) at least one transponder device sends a response signal the waveform and/or the duration of which is/are adjusted according to said stored parameter.

10. A method according to claim 9, further comprising determining the duration parameter and/or the waveform parameter at the beginning of the first transponder devices interrogation sequence.

11. A method according to claim 9, further comprising determining the duration parameter and/or the waveform parameter at the beginning of each transponder devices interrogation sequence.

12. A method according to claim 11, wherein each transponder device is capable of transmitting two different signals, whereby each of these signals has a different waveform.

13. A method according to claim 12, wherein the two response signals are transmitted over two different time slots.

14. A method according to claim 12, wherein the two response signals are transmitted during the same time slot.

15. A system of information exchange between an interrogator device (DI) and at least one transponder devices (E₁, E₂) located in the electromagnetic field of the interrogator device, each of these interrogator and transponder devices comprises means of transmitting/receiving signals (1-4, 6, 11-13) together with electronic means of sequencing (5, 14) and means of recording (10, 15), characterized in that:

said interrogator device (DI) further comprises means for defining a parameter relative to a desired duration and/or waveform of the response signals (S_r) of each transponder device from the analysis of the signal-to-noise ratio between the signal transmitted by the transponder device and the ambient noise, said parameter being then transmitted to each transponder device within the identification sequence start control signal;

each transponder device comprising means for interpreting said control signal, and identifying said parameter so as to transmit a response signal the waveform and/or the duration of which is/are adjusted according to said parameter.

16. A system according to claim 15, wherein each transponder device contains a timer (8) for recording a duration determined according to the ratio between the signal transmitted by the transponder device and the ambient electromagnetic noise, and for counting a transmission time during this duration, and/or at least one shift register (7) for recording a waveform determined according to the ratio between the transmitted signal and the ambient electromagnetic noise and reproducing this waveform each time a signal is transmitted.