RFID COMMUNICATION SYSTEMS AND METHODS, AND RFID READERS AND SYSTEMS

• US 20110193685A1
• Filed: 04/11/2011
• Published: 08/11/2011
• Est. Priority Date: 12/01/2006
• Status: Abandoned Application

• Current Assignee: Round Rock Research LLC
• Original Assignee: Round Rock Research LLC
• Inventors: Tuttle, John R.
• Application Number:
  US13/083,872
• Publication Number:
  US 20110193685A1
• Time in Patent Office: Days
• US Class Current: 340/10.2
• 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 of coordinating a plurality of radio frequency identification device (RFID) readers, the method comprising:

controlling the RFID readers such that only one of the RFID readers performs an inventory of RFID tags, in communications range, at a time.

2. A method in accordance with claim 1 wherein controlling the RFID readers includes controlling handheld RFID readers.

3. A method in accordance with claim 1 wherein the controlling comprises selecting RFID readers, and wherein, if a selected RFID reader is deselected, another RFID reader is selected only if there is no reader energy above a predetermined threshold, detected at the second RFID reader.

4. A method of coordinating a plurality of RFID readers capable of using different sessions, the RFID readers being configured to be used with RFID tags that maintain flags for respective sessions that indicate whether or not the tag has been inventoried for a session, the method comprising:

controlling the RFID readers such that only one of the RFID readers performs an inventory of RFID tags at a time.

5. A method in accordance with claim 4 wherein at least some of the RFID readers include wireless networking hardware and wherein the controlling comprises controlling using the wireless networking hardware.

6. A method in accordance with claim 4 wherein at least some of the RFID readers have Wi-Fi communications capability, and wherein the controlling comprises controlling using the Wi-Fi communications capability.

7. A method in accordance with claim 4 wherein at least some of the RFID readers have Wi-Fi communications capability, and communicate with the tags other than using Wi-Fi communications, and wherein the controlling comprises controlling using the Wi-Fi communications capability.

8. A method in accordance with claim 4 wherein the controlling comprises selecting RFID readers, and wherein, if a selected RFID reader is deselected by the controller, another RFID reader is selected by the controller such that there is no RFID reader energy above a predetermined threshold, at the new selected RFID reader.

9. A method comprising:

determining if multiple RFID readers have inventoried a common RFID tag and, if so, for those RFID readers, inventorying tags one RFID reader at a time.

10. A method in accordance with claim 9 wherein the inventorying tags one RFID reader at a time comprises restarting inventorying that may have already taken place.

11. A method in accordance with claim 9 wherein the inventorying one RFID reader at a time comprises selecting RFID readers using a controller, and wherein, if a selected RFID reader is deselected by the controller, another RFID reader is selected by the controller such that there is no RFID reader energy above a predetermined threshold, at the new selected RFID reader.

12. A method of coordinating a plurality of RFID readers capable of using different sessions, the RFID readers being configured to be used with RFID tags that maintain flags for respective sessions that indicate whether or not the tag has been inventoried for a session, the method comprising:

controlling the RFID readers such that only one of the RFID readers performs an inventory of RFID tags at a time, wherein the inventorying tags one RFID reader at a time comprises restarting inventorying that may have already taken place.

13. A method in accordance with claim 12 wherein at least some of the RFID readers include wireless networking hardware and wherein the controlling comprises controlling using the wireless networking hardware.

14. A method in accordance with claim 13 wherein at least some of the RFID readers have Wi-Fi communications capability, and wherein the controlling comprises controlling using the Wi-Fi communications capability.

15. A method in accordance with claim 12 wherein at least some of the RFID readers have Wi-Fi communications capability, and communicate with the tags other than using Wi-Fi communications, and wherein the controlling comprises controlling using the Wi-Fi communications capability.

16. A method in accordance with claim 12 wherein the controlling comprises selecting from the RFID readers, and wherein, if a selected RFID reader is deselected by the controller for any reason, another RFID reader is selected by the controller such that there is no RFID reader energy above a predetermined threshold, at the new selected RFID reader.

17. A method of observing changes in RFID tag populations, the method comprising:

controlling multiple RFID readers so that only one of the RFID readers conducts an inventory of RFID tags in communications range;

storing a first list of tags inventoried by the RFID reader;

repeating the inventory;

storing a second list of tags inventoried in the repetition of the inventory; and

comparing the first list to the second list to determine if tags are entering or leaving communications range of at least one of the RFID readers.

18. A method in accordance with claim 17 wherein additional of the multiple RFID readers also conduct an inventory of the RFID tags, but only one of the RFID readers conducts an inventory at a time.

19. A method in accordance with claim 17 wherein repeating the inventory comprises using the one RFID reader that conducted the first mentioned conducting of an inventory.

20. A system for coordinating a plurality of RFID readers, the system comprising:

a reader controller configured to control the RFID readers such that only one of the RFID readers performs an inventory of RFID tags, in communications range, at a time.

21. A system in accordance with claim 20 and further comprising a plurality of RFID readers coupled to the reader controller, wherein the RFID readers include handheld RFID readers.

22. A system in accordance with claim 20 wherein the controller is configured to selecting from the RFID readers, and wherein, if a selected RFID reader is deselected by the controller, another RFID reader is selected by the controller where RFID reader energy above a predetermined threshold is not detected at the new selected RFID reader.

23. An RFID communications system, comprising:

a plurality of RFID readers capable of using different sessions, the RFID readers being configured to be used with RFID tags that maintain flags for respective sessions that indicate whether or not the tag has been inventoried for a session; and

a controller configured to control the RFID readers such that only one of the RFID readers performs an inventory of RFID tags at a time.

24. A system in accordance with claim 23 wherein at least some of the RFID readers include wireless networking hardware and wherein the RFID controller is configured to control the RFID readers using the wireless networking hardware.

25. A system in accordance with claim 23 wherein at least some of the RFID readers include Wi-Fi hardware, and wherein the RFID controller is configured to control the RFID readers using the Wi-Fi hardware.

26. A system in accordance with claim 25 wherein at least some of the RFID readers have Wi-Fi communications hardware, and are configured to communicate with the tags other than using Wi-Fi communications, and wherein the RFID controller is configured to control the RFID readers using the Wi-Fi hardware.

27. A system in accordance with claim 25 wherein one of the RFID readers comprises the RFID controller.

28. A system in accordance with claim 23 wherein the controller is configured to selecting from the RFID readers, and wherein, if a selected RFID reader is deselected by the controller, another RFID reader is selected by the controller where RFID reader energy above a predetermined threshold is not read at the new selected RFID reader

29. A system comprising:

an RFID controller configured to determine if multiple RFID readers have inventoried a common RFID tag, by communicating with the multiple RFID readers and comparing lists of RFID tags inventories by RFID readers, and, if so, for those RFID readers, causing the RFID readers to inventory tags one RFID reader at a time.

30. A system in accordance with claim 29 wherein the controller is configured to cause a RFID reader that has inventoried the same RFID tag as another RFID reader to restart inventorying.

31. A system in accordance with claim 29 wherein the controller is configured to select from the RFID readers, and wherein, if a selected RFID reader is deselected by the controller, another RFID reader is selected by the controller which does not read RFID reader energy above a predetermined threshold, which RFID reader energy indicates that another reader is nearby and active.

32. An RFID communications system, comprising:

a plurality of RFID readers capable of using different sessions, the RFID readers being configured to be used with RFID tags that maintain flags for respective sessions that indicate whether or not the tag has been inventoried for a session; and

a controller coupled to the RFID readers and configured to control the RFID readers such that only one of the RFID readers performs an inventory of RFID tags at a time, even though the RFID readers are capable of using different sessions, wherein the controller is configured to selectively cause a RFID reader to restart its inventory.

33. A system in accordance with claim 32 wherein at least some of the RFID readers include wireless networking hardware and wherein the controller is configured to communicate with those RFID readers using the wireless networking hardware.

34. A system in accordance with claim 32 wherein at least some of the RFID readers have Wi-Fi communications hardware and wherein the controller is configured to communicate with those RFID readers using the Wi-Fi communications hardware.

35. A system in accordance with claim 32 wherein at least some of the RFID readers have Wi-Fi communications hardware, and are configured to communicate with RFID tags other than using Wi-Fi communications, and wherein the controller is configured to communicate with those RFID readers using the Wi-Fi communications hardware.

36. A system in accordance with claim 32 wherein the controller is configured to select from the RFID readers, and wherein, if a selected RFID reader is deselected by the controller, another RFID reader is selected by the controller which does not read RFID reader energy above a predetermined threshold, which RFID reader energy indicates that another reader is nearby and active.

37. A system for observing changes in RFID tag populations, the system comprising:

a first RFID reader;

a reader controller configured to control multiple RFID readers so that only the first RFID reader conducts an inventory of RFID tags in communications range at a time, the reader controller causing the first RFID reader to conduct a first inventory session and the reader controller causing the first RFID reader to conduct a second inventory session after the first inventory session;

a database for storing a first list of tags inventoried by the RFID reader in the first inventory session; and

a second database for storing a second list of tags inventoried by the first RFID reader in the second inventory session, the reader controller being configured to compare the first list to the second list to determine if tags are entering or leaving communications range of the RFID reader.

38. A system in accordance with claim 37 and further comprising a second RFID reader controlled by the reader controller.