RFID communication systems and methods, and RFID readers and systems

• US 7,924,141 B2
• Filed: 12/01/2006
• Issued: 04/12/2011
• Est. Priority Date: 12/01/2006
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Round Rock Research LLC
• Inventors: Tuttle, John R.
• Primary Examiner(s): Brown; Vernal U
• Application Number:
  US11/607,263
• Publication Number:
  US 20080129485A1
• Time in Patent Office: 1,593 Days
• Field of Search: 340/10.1, 340/568.1, 340/572.4, 340/825.72, 235/385
• 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 7/10029 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: G06K 7/10128 the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

A method of coordinating a plurality of RFID readers includes controlling the RFID readers such that only one of the readers performs an inventory of RFID tags at a time. A system for coordinating a plurality of RFID readers is also provided.

Claims

1. A method comprising:

a first RFID reader beginning an inventory session, the RFID reader setting a flag on respective RFID tags that have been inventoried by the first RFID reader;

storing information representing the tags that have been inventoried by the first RFID reader;

interrupting the first RFID reader'"'"'s inventory session;

resetting the flags on the tags that have been inventoried;

a second RFID reader beginning an inventory session, the second RFID reader setting a flag on respective RFID tags that have been inventoried;

storing information representing the tags that have been inventoried;

resetting the flags set by the second RFID reader; and

resuming the inventory session of the first RFID reader, the resuming including reflagging the tags for which information was stored representing the tags that were inventoried by the first RFID reader.

2. A method in accordance with claim 1 wherein the storing of information representing the tags that have been inventoried by the first RFID reader comprises storing the information representing the tags that have been inventoried by the first RFID reader in the first RFID reader.

3. A method in accordance with claim 1 wherein setting a flag on respective RFID tags that have been inventoried by the first RFID reader comprises setting a bit on respective RFID tags.

4. A method in accordance with claim 1 wherein setting a flag on respective RFID tags that have been inventoried by the first RFID reader comprises setting a lockout bit on respective RFID tags.

5. A method in accordance with claim 1 wherein setting a flag on respective RFID tags that have been inventoried by the first RFID reader comprises setting a sessions bit on respective RFID tags.

6. A method in accordance with claim 1 wherein storing information representing the tags that have been inventoried by the first RFID reader comprises storing information in a database.

7. A method in accordance with claim 6 wherein storing information representing the tags that have been inventoried by the second RFID reader comprises storing information in a second database.

8. A method in accordance with claim 1 and further comprising interrupting the inventory session of the second RFID reader prior to resetting the flags set by the second RFID reader.

9. A method in accordance with claim 1 and further comprising completing the inventory session of the second RFID reader prior to resetting the flags set by the second RFID reader.

10. A system comprising:

a first RFID reader configured to conduct an inventory session, the first RFID reader being configured to set a flag on respective RFID tags that have been inventoried by the first RFID reader and to store information representing the tags that have been inventoried by the first RFID reader as they are being inventoried, the first RFID reader being capable of being selectively interrupted in its inventory session, the first RFID reader being configured to reset the flags on the tags that have been inventoried in response to being interrupted; and

a second RFID reader configured to conduct an inventory session, the first RFID reader being configured to set a flag on respective RFID tags that have been inventoried by the second RFID reader and to store information representing the tags that have been inventoried by the second RFID reader as they are being inventoried, and being configured to reset the flags set by the second RFID reader when it is time for the first RFID reader to resume its inventory session, wherein the first RFID reader is further configured to reflag the tags for which information was stored representing the tags that were inventoried by the first RFID reader prior to resuming its interrupted inventory session.

11. A system in accordance with claim 10 and further comprising an RFID tag having a bit representing the flag that is used to indicate whether the tag has been inventoried.

12. A system in accordance with claim 10 wherein the information representing the tags that have been inventoried comprises a tag ID number.

13. A system in accordance with claim 10 and further comprising an RFID tag having a lockout bit representing the flag that is used to indicate whether the tag has been inventoried.

14. A system in accordance with claim 10 and further comprising an RFID tag having a sessions bit representing the flag that is used to indicate whether the tag has been inventoried.

15. A system in accordance with claim 10 wherein the first RFID reader comprises a database to store information representing the tags that have been inventoried by the first RFID reader.

16. A system in accordance with claim 15 wherein the second RFID reader comprises a database to store information representing the tags that have been inventoried by the second RFID reader.

17. A system in accordance with claim 10 wherein the second RFID reader is configured to reset the flags set by the second RFID reader in response to the second RFID reader'"'"'s inventory session being interrupted.

18. A system in accordance with claim 10 wherein the second RFID reader is configured to reset the flags set by the second RFID reader in response to the second RFID reader'"'"'s inventory session being completed.