Method of identifying a plurality of transponders, analysis apparatus and a transponder for implementing such a method

• US 6,483,426 B1
• Filed: 12/07/1998
• Issued: 11/19/2002
• Est. Priority Date: 12/10/1997
• Status: Expired due to Fees

• Current Assignee: Frédéric Pagnol, Saak Dertadian
• Original Assignee: Frédéric Pagnol, Saak Dertadian
• Inventors: Dertadian, Saak, Pagnol, Frédéric
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): Dalencourt, Yves
• Application Number:
  US09/207,317
• Time in Patent Office: 1,443 Days
• Field of Search: 340/10.1, 340/10.2, 340/10.31, 340/10.33, 340/10.42, 340/5.8, 340/572.1, 342/42, 342/44, 710/46
• 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
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence

Abstract

A method identifying a set of transponders situated in the interrogation field of analysis apparatus, with each transponder storing a different identity code. The analysis apparatus first transmits data, and each unidentified transponder compares this data with a portion of its own identity code, which portion is selected by the analysis apparatus, and then transmits in a time window, selected at least as a function of the result of the comparison. The analysis apparatus, then receives the data transmitted by the transponders, determines whether data enables any of the transponders identity codes. The analysis apparatus then emits modified data so that after a finite number of iterations the data causes each of the transponders to transmit data enabling the individual transponder'"'"'s identity code to be determined.

Claims

1. A method of identifying a set of transponders situated in the field of an analysis apparatus, each transponder having a different identity code in memory, the method comprising:

a) causing the analysis apparatus to transmit data for comparison with a portion of the identity code as selected by the analysis apparatus, said portion comprising a byte;

b) causing each as-yet unidentified transponder to compare the received data and the portion of its identity code as selected by the analysis apparatus;

c) causing each as-yet unidentified transponder to transmit in at least one time window selected from a set of time windows common to the set of transponders as a function of the result of said comparison; and

d) causing the analysis apparatus to analyze the data transmitted by the transponders in said set of time windows, and when the data transmitted by the transponders does not enable a transponder identity code to be determined, at least in part, causing the apparatus to start again with data that has been modified in such a manner that, within a finite number of iterations, the transponders are caused to transmit data enabling the identity code of at least one of the transponders to be determined, at least in part.

2. A method according to claim 1, wherein each transponder includes a comparison register in which the data for comparison is stored.

3. A method according to claim 2, wherein said comparison register is organized to store a plurality of binary words, wherein the identity code is constituted by binary words, wherein the analysis apparatus (3) modifies, one at a time, a binary word of given significance (n) in the comparison register, and wherein each as-yet unidentified transponder compares the most-recently modified binary word and the binary word of corresponding significance in the identity code of the transponder, the portion of the identity code on which comparison is to be performed being selected by selecting the significance of each new binary word that is to be stored in the comparison register.

4. A method according to claim 3, wherein each transponder transmits in a first set of time windows the result of comparing the most-recently modified binary word and the portion of the identity code of the transponder that has been selected by the analysis apparatus, providing the bytes of the identity code of the transponder already determined by the analysis apparatus are respectively equal to the corresponding bytes of the comparison register, and transmits in a second set of time windows the result of comparing the entire comparison register with the entire identity code.

5. A method according to claim 4, wherein said second set of time windows is reduced to a single time window in which each transponder transmits in the event of a match between the comparison register of the transponder and the identity code of the transponder.

6. A method according claim 1, further comprising:

causing the analysis apparatus, whenever the data previously received thereby makes this possible, to determine at least a portion of the identity code of one or more transponders, to send an order causing said transponder(s) to transmit its/their identity code(s); and

analyzing said identity code(s) as received to determine whether only one identity code was transmitted or whether there has been interference associated with a plurality of different codes being transmitted, and in the event of only one identity code being received, storing said code.

7. A method according to claim 6, wherein when a plurality of transponders transmit a plurality of different identity codes simultaneously and they interfere with one another, the method further includes the step consisting in sending new data to be compared with a new portion of the identity code in said transponders, other than the portion already determined by the analysis apparatus, optionally in modifying said new data until said new identity code portion has been determined, and thereafter in causing the transponder(s) for which the new identity code portion has been determined to transmit its/their identity code(s), and in the event of interference restarting the process for determining the identity code again by causing the comparison to be performed on an as-yet undetermined portion of the identity code, until only one identity code is received from the transponders.

8. A method according to claim 1, wherein each identified transponder is put into a standby mode in which the transponder ceases to transmit the result of comparing the identity code of the transponder with the data transmitted by the analysis apparatus.

9. A method according to claim 8, wherein each transponder that has been identified is put into said standby mode by using the analysis apparatus to transmit the identity code of the transponder.

10. A method according to claim 2, wherein each transponder whose comparison register is equal to the identity code of the transponder puts the transponder into a standby mode.

11. A method of identifying the serial number of all the transponders in a plurality of transponders located simultaneously in the field of an analysis apparatus, each transponder having a comparison register capable of storing a plurality of bytes, in which method;

a) a byte of given significance of the comparison register in all of the unidentified transponders is loaded with a value by causing the analysis apparatus to send an order to write said value in said byte;

b) within each transponder said byte of given significance is compared with the byte of corresponding significance in the serial number of the transponder;

c) for this byte of given significance of the comparison register, and depending on the result of the comparison, greater than, or equal to, or less than, every as-yet unidentified transponder transmits a response respectively in a first, a second, or a third time window of a group of three time windows associated with the significance of the byte on which the comparison has been performed, said group being selected from a plurality of time window groups respectively associated with bytes of different significance of the comparison register, each as-yet unidentified transponder transmitting the result of comparing the byte of given significance most recently loaded into the comparison register with the corresponding byte of the serial number of the transponder, with the proviso, when the byte of given significance on which comparison is being performed is not the least significant byte, respectively the most significant, that there is a match between the less significant bytes, respectively the more significant, of the comparison register and the corresponding bytes of the serial number;

d) the analysis apparatus is caused to analyze the responses, and;

when none of the responses corresponds to a match between the byte of given significance most recently loaded into the comparison register and the byte of corresponding significance in the serial number, the method begins again at above step a) by modifying the value previously loaded into the comparison register at the same address by a range-halving technique so as to reach a situation in which the analysis apparatus detects a response corresponding to the fact that the value of the byte of given significance in the comparison register matches the byte of corresponding significance in the serial number;

if one of the responses corresponds to the fact that there is a match between the byte of given significance in the comparison register and the byte of corresponding significance in the serial number, the analysis apparatus is caused to send a read order causing every transponder for which a match has occurred to send its serial number;

if the serial numbers transmitted by the transponders are unable to be read because of mutual interference, a given value is loaded into the next most, respectively least, significant byte of the comparison register, and said value is modified by a range-halving technique until analysis of the responses from the transponders indicates a match with the corresponding byte of the serial number; and

when a serial number can be read because only one transponder is responding, said serial number is stored.

12. A method of identifying the serial number of each transponder in a plurality of transponders placed simultaneously in the field of an analysis apparatus, each transponder having a comparison register capable of storing a plurality of bytes, in which method:

a) a byte of given significance of the comparison register of every unidentified transponder is loaded with a value by the analysis apparatus transmitting an order to write said value in said byte;

b) said byte of given significance is compared within each transponder with the byte of corresponding significance in the serial number of the transponder;

c) depending on the result of the comparison, greater than, equal to, or less than, each unidentified transponder transmits a response respectively in a first, a second, or a third time window, providing the serial number bytes of significance smaller, respectively higher, than the byte on which a comparison is actually being performed are all equal to the corresponding bytes of the comparison register;

d) within each unidentified transponder, the comparison register is compared with the serial number and if they match, the transponder transmits in a fourth time window and then after transmitting in said fourth time window, the transponder is put into a standby mode;

e) the analysis apparatus analyzes the responses; and

f) in the event of a transmitter transmitting in said fourth time window, its serial number is determined as a function of the data that has been stored in the comparison register of that transponder;

g) in the event of none of the responses corresponding to a match between the byte of the most-recently given significance loaded into the comparison register and the byte of corresponding significance of the serial number, the method starts again at above step a) after modifying the value previously loaded into the comparison register at the same address so as to reach, by a range-halving technique, the situation in which the analysis apparatus detects a response corresponding to the fact that the value of the byte of given weight in the comparison register matches the byte of corresponding weight in the serial number of at least one transponder;

h) if there is a response corresponding to the fact that there is a match between the byte of given weight in the comparison register and the byte of corresponding weight of the serial number, the analysis apparatus sends a read order causing every transponder in which said match has occurred to transmit the serial number of the transponder;

i) if the serial numbers transmitted by the transponders are unable to be read in step h) because of interference, the byte of the comparison register having the next greater, respectively smaller, significance is loaded with a given value, and said value is modified, where necessary, by a range-halving technique so as to obtain, on analyzing the responses delivered by the transponders, a response corresponding to the fact that there is a match between the value of the byte of given significance most recently loaded into the comparison register and the corresponding portion of the serial number in at least one transponder, in which case a read order is transmitted causing every transponder for which there is a match to transmit the serial number of the transponder;

j) when a serial number is read because only one transponder is responding, said serial number is stored and then the comparison registers of all the transponders are loaded with this serial number so as to put the transponder which responded in standby mode; and

k) if the serial numbers transmitted by the transponders are unable to be read because of interference, the method starts again at step i).

13. A transponder comprising an identification code including a serial number stored in a memory and means for remote communication with an analysis apparatus the transponder comprising a comparison register in which data from the analysis apparatus can be stored, calculation means for comparing at least a portion of the identity code, said portion comprising a byte, with at least a portion of the comparison register, and means for transmitting the result of the comparison in at least one time window selected from a set of time windows, said at least one time window depending on the result of the comparison.

14. A transponder according to claim 13, wherein the comparison register (H) is constituted by a plurality of binary words (H₃, H₂, H₁, H₀) of different significance, and by the fact that said calculation means (10) are organized to compare the binary word (H_n, m) most recently stored in the register with a binary word of corresponding significance (S_n) of the identity code.

15. A transponder according to claim 14, wherein the transponder is organized to transmit the result of the comparison between the binary word most recently stored in the register and the binary word of corresponding significance of the serial number, except in the event of the comparison being performed on a word other than the least, respectively most, significant binary word and there is no match between the binary word(s) of significance less, respectively higher, than that of the word most recently stored in the register and the corresponding binary word(s) of the identity code.

16. A transponder according to claim 13, wherein the comparison register has four bytes.

17. A transponder according to claim 13, wherein the transponder is organized to transmit the result of the comparison only once when the contents of the comparison register matches the identity code.

18. A transponder according to claim 14, wherein the transponder is organized to transmit the result of comparing the binary word most recently stored in the comparison register of the transponder and the word of corresponding significance of the serial number of the transponder in one of three time windows corresponding respectively to the case where the result of the comparison is less than, equal to, and greater than.

19. A transponder according to claim 18, wherein the transponder is organized also to transmit in a fourth time window when the serial number of the transponder matches the comparison register.

20. Analysis apparatus for a plurality of transponders having different identity codes, comprising processor means organized to determine the identity codes of a plurality of transponders placed in the field of the analysis apparatus, said analysis apparatus being suitable for;

transmitting a write order associated with identity data, said order causing said identity data to be stored in the transponders at a particular address selected by the analysis apparatus;

analyzing the response from as-yet unidentified transponders in a set of time windows after said identity data has been transmitted;

transmitting a read order to cause the transponders whose identity codes have been determined in part to send their identity codes in full;

transmitting a new write order associated with new identity data in the event of interference between the data transmitted by the transponders, so as to end up by causing only one transponder at a time to send its identity code, and storing said code; and

repeating the above steps so as to identify all of the transponders in turn, wherein the analysis apparatus is suitable for;

analyzing the responses of as-yet unidentified transponders in four time windows, three of the time windows corresponding to the results of comparisons performed by the as-yet unidentified transponders between the identity data most recently stored in the transponders and a portion of their respective identity codes as determined by the address selected by the analysis apparatus, transmission by a transponder in the fourth time window corresponding to the fact that the identity code of the transponder matches the entire identity data stored by said transponder in the various selected addresses.

21. Apparatus according to claim 20, wherein the analysis apparatus is suitable for:

analyzing the responses of as-yet unidentified transponders in four time windows, three of the time windows corresponding to the results of comparisons performed by the as-yet unidentified transponders between the identity data most recently stored in the transponders and a portion of their respective identity codes as determined by the address selected by the analysis apparatus, transmission by a transponder in the fourth time window corresponding to the fact that the identity code of the transponder matches the entire identity data stored by said transponder in the various selected addresses.

22. Apparatus according to claim 20, wherein the apparatus includes an antenna constituted by a solenoid in which the transponders are placed.

23. A method of enabling transponders situated in the field of an analysis apparatus to be identified, each transponder having a different identity code, the method comprising:

a) using the analysis apparatus to transmit data to be compared with a portion of the identity code selected by the analysis apparatus, said portion comprising a byte;

b) within each unidentified transponder, comparing the received data and a corresponding portion of the transponder'"'"'s identity code;

c) causing each unidentified transponder to transmit in at least one time window selected from a set of time windows common to the set of transponders;

d) using the analysis apparatus to analyze the data transmitted by the transponders in said set of time windows, and when the data transmitted by the transponders does not enable at least part of the identity code of at least one of the transponders to be identified, beginning again with data modified in such a manner that, after a finite number of iterations, the transponders transmit data to determine at least a part of the identity code of at least one of the transponders;

e) causing the analysis apparatus, when the data previously received thereby to determine at least a portion of the identity code of one or more transponders, to transmit an order causing every such transponder to transmit its own identity code; and

f) analyzing reception of the identity code to determine whether a single identity code has been transmitted or whether interference has occurred associated with simultaneous transmission of a plurality of different codes, and when only one identity code is received, storing said code.

24. Analysis apparatus and a set of transponders for implementing the method defined in claim 23.

25. A method of identifying a set of transponders situated in the field of an analysis apparatus, each transponder having a different identity code, the method comprising:

a) causing the analysis apparatus to transmit data comprising more than one bit,

b) causing unidentified transponders to compare said data and a portion of their identity code comprising more than one bit to determine whether said data are inferior, superior or equal to said portion of their identity code,

c) causing said unidentified transponders to transmit the result of said comparison, and

d) causing the analysis apparatus to analyze the data transmitted by the transponders, and when the data transmitted by the transponders does not enable a transponder identity code to be determined at least in part, causing the apparatus to start again with data that has been modified.

26. A transponder comprising:

an identity code,

a receiver being configured for remote communication with an analysis apparatus, and

a comparison register in which data transmitted by the analysis apparatus can be stored,

said transponder being configured to determine whether said data stored in the comparison register are inferior, superior or equal to at least a portion of the identity code, comprising more than one bit.

27. An analysis apparatus for a plurality of transponders having different identity codes, comprising processor means organized to determine the identity codes of a plurality of transponders, said analysis apparatus being suitable for:

transmitting a write order associated with identity data to be stored in the transponders,

analyzing the response from the transponders in a set of time windows corresponding to the results of comparisons performed by the transponders between the identity data most recently stored in the transponders and a portion of their identity code as selected by the analysis apparatus,

transmitting a new write order associated with new identity data,

repeating the above steps so as to identify all of the transponders in turn.

28. A transponder comprising an identification code and an emitter and receiver for remote communication with an analysis apparatus, the transponder comprising a comparison register in which data transmitted by the analysis apparatus and to be compared to at least a portion of the identity code can be stored, said portion comprising more than one bit, wherein the receiver is arranged for transmitting the result of the comparison in at least one time window selected from a set of time windows, depending on the result of the comparison.

29. A transponder comprising:

an identity code;

a comparison register in which data from an analysis apparatus can be stored;

a calculator for comparing at least a portion of the identity code with at least a portion of the comparison register; and

an emitter for transmitting the result of the comparison in at least one time window selected from a set of time windows, the at least one selected time window depending on the result of the comparison, said result being one of superior, inferior or equal.

30. A transponder comprising:

an identity code;

a receiver for remote communication with an analysis apparatus; and

a calculator for comparing at least one portion of the identity code with data received from the analysis apparatus, to determine whether said data is inferior, superior or equal to said at least one portion of the identity code.

31. A transponder comprising:

a serial number;

a comparison register in which data from an analysis apparatus can be stored;

a calculator for comparing at least a portion of the serial number with at least a portion of the comparison register; and

an emitter for transmitting the result of the comparison in at least one time window selected from a set of time windows, the at least one selected time window depending on the result of the comparison, said result being one of superior, inferior equal.

32. A transponder comprising:

an identity code;

a comparison register in which data from an analysis apparatus can be stored;

an emitter; and

a calculator being configured to supply said emitter with information representative of the result of a comparison between at least a part of said identity code and data stored in the comparison register, said result being one of superior, inferior or equal.