RFID ANTENNA SELECTION SYSTEM AND METHOD

• US 20090102610A1
• Filed: 10/06/2008
• Published: 04/23/2009
• Est. Priority Date: 10/22/2007
• Status: Abandoned Application

• Current Assignee: Stanley Works Limited (Stanley Black & Decker, Inc.)
• Original Assignee: Stanley Works Limited (Stanley Black & Decker, Inc.)
• Inventors: LANCE, Carl
• Application Number:
  US12/245,954
• Publication Number:
  US 20090102610A1
• Time in Patent Office: Days
• US Class Current: 340/10.200
• 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 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles

Abstract

A method and apparatus for reading a plurality of RFID tags using a plurality of antennas includes ranking a plurality of antennas based on RFID tags readable, wherein the antenna that can read most RFID tags receives a highest ranking, and the antenna that can read the most RFID tags that were not read by another, higher ranked antenna receives the next highest ranking, progressively until each of the antennas are ranked. During a read operation, the antennas are used in series to read the RFID tags, commencing with using the highest ranking antenna and subsequently using the antennas with progressively lower ranking to read the RFID tags.

Claims

1. A method of reading a plurality of RFID tags using a plurality of antennas, the method comprising:

ranking a plurality of antennas based on RFID tags readable thereby, wherein the antenna that can read the most RFID tags will receive a highest ranking, and the antenna that can read the most RFID tags that were not read by another, higher ranked antenna will receive the next highest ranking, progressively until each of the antennas are ranked; and

executing a read operation wherein at least two of the antennas are used in series to read the RFID tags, commencing with using the highest ranking antenna and subsequently using the antennas with progressively lower rankings to read the RFID tags.

2. A method as in claim 1, where ranking a plurality of antennas comprises:

determining, for each of the antennas in the plurality of antennas, which RFID tags are readable;

storing, for each of the antennas, data indicating which RFID tags are readable thereby;

selecting one of the antennas from the plurality of antennas having the largest number of RFID tags readable and ranking it by the highest ranking;

subsequently determining, for each of the antennas other than the previously ranked antennas, which of the antennas can read a largest number of RFID tags, excluding the RFID tags readable by the previously ranked antennas, and ranking that antenna with the subsequent highest ranking in descending order;

progressively repeating the ranking step until all of the plurality of antennas are ranked by the descending order of rank.

3. A method as in claim 1, further comprising:

interrupting the read operation prior to completing the read operation for all of the plurality of antennas; and

determining a likelihood that the read operation has read all of the plurality of RFID tags.

4. A method as in claim 3, wherein the likelihood is determined based on the stored data.

5. A method as in claim 1, wherein when the read operation is not interrupted prior to completing the read operation for all of the plurality of antennas, the method further comprising:

re-ranking the plurality of antennas based on RFID tags readable thereby, wherein the antenna that can read the most RFID tags receives a highest ranking, and the antenna that can read the most RFID tags that were not read by another, higher ranked antenna will receive the next highest ranking, progressively until each of the antennas are ranked.

6. A method as in claim 1, wherein a single reader is used for the determining which tags are readable and for the read operation.

7. A method as in claim 1, further comprising, making available for use information indicative of items tagged with the read RFID tags.

8. A method as in claim 7, wherein the information is human readable information.

9. A method as in claim 7, wherein the information is machine-readable information.

10. A storage structure comprising:

a storage compartment having space to store a plurality of items;

a plurality of antennas, configured to transmit electromagnetic energy to interrogate a plurality of RFID tags, disposed on at least some items stored in the storage compartment;

at least one RFID reader, operatively connected to the plurality of antennas, and configured to independently control a read operation of each antenna of the plurality of antennas;

a memory, configured to receive and store information output by the RFID reader, the information being sufficient to identify, for each antenna, a number of readable RFID tags and an identity of each of the readable RFID tags; and

a processor, configured to access the memory and to rank the antennas, in accordance with the stored information, wherein the antenna that can read the most RFID tags that were not read by another, higher ranked antenna receives the next highest ranking, progressively until each of the antennas are ranked.

11. A storage structure of claim 10, where the storage compartment is arranged to support the at least one plurality of antennas arranged to transmit electromagnetic energy into the interior of the storage compartment and receive electromagnetic signals from the interior of the storage compartment.

12. A storage structure of claim 10, where the storage compartment comprises at least one shelf arranged to support at least one of the plurality of items.

13. A storage structure of claim 12, where each shelf incorporates one plurality of antennas.

14. A storage structure of claim 13, where the plurality of antennas incorporated in each shelf is arranged to receive only electromagnetic signals carrying information that distinguish the RFID tags stored on particular shelf that incorporates said plurality of antennas.

15. A storage structure of claim 10, where the RFID reader, the memory, and the processor are integrated in a control unit arranged to control at least one plurality of the antennas.

16. A control unit of claim 15, where the control unit comprises a multiplexer circuit that uses a dedicated reader to control read operations from each plurality of the antennas.

17. A control unit of claim 15 where the control unit comprises a multiplexer circuit that uses a single reader to control read operations from all antennas.

18. A storage structure of claim 12 where the shelves, the RFID reader, the memory, and the processor are integrated in a cart unit capable to be placed and operate separately and independently from any other storage structure.

19. A method of reading a plurality of RFID tags using a plurality of antennas, the method comprising:

assigning a level to each antenna based on RFID tags readable thereby, wherein the antennas that are necessary to achieve a particular read redundancy level for the tags will be assigned to that level;

setting a desired read redundancy level; and

executing a read operation wherein at least those antennas assigned to a level less than the set level are used in series to read the RFID tags, commencing with using the lowest level antennas and subsequently using the antennas with progressively higher levels to read the RFID tags.