Method for repeating interrogations until failing to receive unintelligible responses to identify plurality of transponders by an interrogator

• US 5,929,801 A
• Filed: 07/11/1997
• Issued: 07/27/1999
• Est. Priority Date: 07/11/1997
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Aslanidis, Konstantin O., Berthon, Alain
• Primary Examiner(s): Luu, Le Hien
• Application Number:
  US08/893,822
• Time in Patent Office: 746 Days
• Field of Search: 342/44, 342/51, 342/42, 342/50, 340/825.54
• US Class Current: 342/44
• CPC Class Codes: G06K 7/10029 the collision being resolved in the time domain, e.g. using binary tree search or RFID responses allocated to a random time slot
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming

Abstract

A novel addressing scheme for an RF-ID system or LAN network is presented in which an interrogator(reader) addresses a set of transponders, each transponder in this set having a common addressing scheme, and the addressed transponders respond only upon the matching of their own address with the received addressing scheme. The addressing scheme comprises a fixed size sub-address and a variable size mask. For example, assuming that the transponder address is 32 bits, the implementation of the addressing scheme can choose 4 bits for the size of the sub-address and 0, 4, 8, 12, 16, 20, 24, 28 bits for the size of the mask. By varying the addressing scheme according to the algorithm in FIG. 4, the reader will in time interrogate all the transponders individually, thus receiving their unique address and achieving the requested exhaustive inventory.

Claims

1. A method of identifying a multitude of transponders within a given interrogation field of an RF-ID system comprising the steps of:

transmitting a first series of powering interrogation pulses comprised of addresses for enabling the transponders, wherein said transponders have unique identification codes and have an address assimilated from at least one bit of said identification code and respond if said address matches said address transmitted from an interrogator;

listening for responses from said transponders and upon receipt of unintelligible responses at some addresses, then storing said addresses in said memory;

transmitting a second series of powering interrogation pulses comprised of addresses wherein said addresses comprise a concatenation of a mask and a sub-address, and said mask comprises one of said stored addresses and said sub-address comprises a successive series of addresses;

listening for responses from said transponders and upon receipt of unintelligible responses at some addresses comprised of said concatenation of said mask and sub-address, then storing said addresses comprised of a concatenation of said mask and sub-addresses in said memory; and

wherein said steps of listening for responses and receipt of unintelligible responses at some address and storing said concatenation of said mask and sub-address which comprise said address and said step of transmission of a series of interrogation pulses comprised of addresses wherein said addresses comprises a concatenation of said mask and sub-address wherein said mask comprises one of said stored addresses and said sub-address comprises a successive series of addresses repeats until the interrogator fails to receive an unintelligible response.

2. The method of claim 1, wherein said successive series of addresses comprises the addresses from 0 to 2^{sub-address-size} -1.

3. The method of claim 1, wherein the interrogator transmits a fixed size sub-address and a variable size mask.

4. The method of claim 3, wherein with each transmission of said interrogation pulses, said mask size increases.

5. The method of claim 1, further comprising step of determining an amount of time it takes to identify T transponders is 0.4*T*Selective_-- Poll_-- Command_-- time+T* transponder_-- response_-- time, wherein transponder_-- response_-- time is the amount of time it takes for a transponder to respond and Selective Poll Command time is the duration of the interrogation powering pulse.

6. The method of claim 1, wherein said first series of interrogation pulses, mask size is null.

7. The method of claim 4, wherein said mask size increases as a result of collisions resulting at some collision addresses wherein said collision addresses are comprised of a concatenation of said mask and sub-address, and said concatenation of mask and sub-address becomes the mask for the next series of interrogation pulses.

8. The method of claim 1, wherein said sub-addresses are also assimilated from at least one bit of said transponder identification code.

9. The method of claim 1, wherein upon being identified, said transponder receives a quiet command along with it'"'"'s address for disabling said transponder until further notice.

10. A method of identifying a multitude of transponders within a given interrogation field of an RF-ID system comprising the steps of:

transmitting a powering interrogation pulse and addresses within an interrogation field to transponders within said field for enabling the transponders, wherein said transponders have unique identification codes and have an address assimilated from at least one bit of said identification code and respond if said address matches said address transmitted from an interrogator;

listening for responses from said transponders and upon receipt of an unintelligible response, transmitting a command instructing said transponders in said field as yet unidentified to use as a sub-address a different set of bits within said identification code;

transmitting a powering interrogation pulse and a successive series of addresses within an interrogation field to transponders within said field for enabling the transponders;

listening for responses from said transponders wherein said transponders respond upon receipt of said address from said interrogator which matches said transponder'"'"'s sub-address, and;

wherein said listening for responses and receipt of unintelligible responses and transmission of said command instructing said transponders in said field as yet unidentified to use as a sub-address a different set of bits within said identification code than previously used and transmission of a successive series of addresses repeats until the interrogator fails to receive an unintelligible response.

11. The method according to claim 10, wherein said successive series of addresses comprise the addresses from 0 to 2^{sub-address-size} -1.

12. The method according to claim 10, wherein the interrogator transmits a fixed size address and a variable position mask.

13. The method according to claim 12, wherein with each transmission of said interrogation pulses, said mask position changes.

14. The method according to claim 10, wherein said sub-addresses are also assimilated from at least one bit of said transponder identification code.

15. The method according to claim 10, wherein upon being identified, said transponder receives a quiet command along with it'"'"'s address for disabling said transponder until further notice.

16. A method of identifying a multitude of remote units within a given network in a data information transfer system comprising the steps of:

polling said network comprised of a command center and remote stations with a particular address of at least one station, wherein said stations have unique identification codes and have an address assimilated from at least one bit of said identification code and respond if said address matches said address transmitted from said command center;

receiving an unintelligible response indicative of more than one station having said particular address;

transmitting a command instructing said stations on said network as yet unidentified to use as a sub-address a different set of bits within said identification code;

transmitting a successive series of addresses;

polling for responses from said stations wherein said stations respond upon receipt of said address from said command center which matches said station'"'"'s sub-address;

wherein said polling for responses and receipt of unintelligible responses and transmission of said command instructing said stations in said field as yet unidentified to use as a sub-address a different set of bits within said identification code than previously used and transmission of a successive series of addresses repeats until the command center fails to receive an unintelligible response.

17. The method according to claim 16, wherein said successive series of addresses comprise the addresses from 0 to 2^{sub-address-size} -1.

18. The method according to claim 16, wherein the command center transmits a fixed size address and a variable position mask.

19. The method according to claim 18, wherein with each transmission of said command, said mask position changes.

20. The method according to claim 16, wherein said successive series of addresses are also assimilated from at least one bit of said station identification code.

21. The method according to claim 16, wherein upon being identified, said station receives a quiet command along with it'"'"'s address for disabling said station until further notice.

22. A method of identifying a multitude of remote units within a given network in a data information transfer system comprising the steps of:

polling said network comprised of a command center and remote stations with a particular address of at least one station, wherein said stations have unique identification codes and have an address assimilated from at least one bit of said identification code and respond if said address matches said address transmitted from said command center;

listening for responses from said stations and upon receipt of unintelligible responses at some addresses, then storing said addresses in said memory;

transmitting a second series of polls pulses comprised of addresses wherein said addresses comprise a concatenation of a mask and a sub-address, and said mask comprises one of said stored addresses and said sub-address comprises a successive series of addresses;

listening for responses from said stations and upon receipt of unintelligible responses at some addresses comprised of said concatenation of said mask and sub-address, then storing said addresses comprised of a concatenation of said mask and sub-addresses in said memory; and

wherein said steps of listening for responses and receipt of unintelligible responses at some address and storing said concatenation of said mask and sub-address which comprise said address and said step of transmission of a series of interrogation pulses comprised of addresses wherein said addresses comprises a concatenation of said mask and sub-address wherein said mask comprises one of said stored addresses and said sub-address comprises a successive series of addresses repeats until the command center fails to receive an unintelligible response.

23. The method of claim 22, wherein said successive series of addresses comprises the addresses from 0 to 2^{sub-address-size} -1.

24. The method of claim 22, wherein the command center transmits a fixed size sub-address and a variable size mask.

25. The method of claim 24, wherein with each transmission of said polls, said mask size increases.

26. The method of claim 22, further comprising step of determining an amount of time it takes to identify T stations is 0.4*T*Selective_-- Poll_-- Command_-- time+T*station_-- response_-- time, wherein station_-- response_-- time is the amount of time it takes for a station to respond and Selective Poll Command time is the duration of the poll.

27. The method of claim 24, wherein said first series of polls, mask size is null.

28. The method of claim 25, wherein said mask size increases as a result of collisions resulting at some collision addresses wherein said collision addresses are comprised of a concatenation of said mask and sub-address, and said concatenation of mask and sub-address becomes the mask for the next series of polls.

29. The method of claim 22, wherein said sub-addresses are also assimilated from at least one bit of said station identification code.

30. The method of claim 22, wherein upon being identified, said station receives a quiet command along with it'"'"'s address for disabling said station until further notice.