Verification of singulated RFID tags by RFID readers

• US 20070257776A1
• Filed: 04/28/2006
• Published: 11/08/2007
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Arnold, Jens, Soleimani, Mohammad, Molina, Victor, Kim, Seok
• Granted Patent: US 7,479,874 B2
• 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 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Methods, systems, and apparatuses for verifying singulated tags are described. A radio frequency (RF) signal is transmitted to provide power to at least one tag. A powered tag is singulated. A delay time period is waited. A read verify command is transmitted to the singulated tag. A response is received to the read verify command. The response to the read verify command is verified to determine whether it was received from the singulated tag.

Claims

1. A method for reading a tag, comprising:

(a) transmitting a radio frequency (RF) signal to provide power to at least one tag;

(b) singulating a powered tag;

(c) waiting a delay time period;

(d) transmitting a read verify command to the singulated tag;

(e) receiving a response to the read verify command; and

(f) verifying that the response to the read verify command was received from the singulated tag.

2. The method of claim 1, wherein step (b) comprises:

transmitting at least one singulate command; and

receiving an identification number from the powered tag.

3. The method of claim 2, wherein step (f) comprises:

determining whether the identification number received from the singulated tag in step (b) matches an identification number received in step (e).

4. The method of claim 3, further comprising:

(g) disregarding the singulated tag if the identification number received from the singulated tag in step (b) does not match the identification number received in step (e).

5. The method of claim 3, further comprising:

(g) accepting the singulated tag if the identification number received from the singluated tag in step (b) matches the identification number received in step (e).

6. The method of claim 1, wherein step (a) comprises:

transmitting an optional wake up command to the at least one tag.

7. The method of claim 2, wherein step (b) comprises:

formatting the singulate command according to an EPC Gen 2 communications protocol.

8. The method of claim 2, wherein step (b) comprises:

formatting the singulate command according to a binary traversal RFID communications protocol.

9. The method of claim 2, wherein step (b) comprises:

formatting the singulate command according to a slotted Aloha RFID communications protocol.

10. A system for reading a tag, comprising:

means for transmitting a radio frequency (RF) signal to provide power to at least one tag;

means for singulating a powered tag;

means for waiting a delay time period;

means for transmitting a read verify command to the singulated tag;

means for receiving a response to the read verify command; and

means for verifying that the response to the read verify command was received from the singulated tag.

11. A radio frequency identification (RFID) reader, comprising:

an antenna; and

logic that includes a tag power module, a tag singulate module, and a read verify module;

wherein the tag power module is configured to transmit a radio frequency (RF) signal from the antenna to provide power to at least one tag;

wherein the tag singulate module is configured to transmit a singulate command from the antenna to singulate a powered tag;

wherein the read verify module is configured to transmit a read verify command to the singulated tag after a delay time period; and

wherein the read verify module is further configured to verify that a response received to the read verify command was received from the singulated tag.

12. The reader of claim 11, wherein the tag singulate module is configured to receive an identification number from the powered tag in response to the singulate command.

13. The reader of claim 12, wherein the read verify module is configured to determine whether the identification number received from the singulated tag in step (b) matches an identification number received in step (e) to verify that the response was received from the singulated tag.

14. The reader of claim 13, wherein the singulated tag is disregarded by the reader if the identification number received from the singulated tag in step (b) does not match the identification number received in step (e).

15. The reader of claim 13, wherein the singulated tag is accepted by the reader if the identification number received from the singulated tag in step (b) matches the identification number received in step (e).

16. The reader of claim 11, wherein the tag power module is further configured to transmit a wake up command to the at least one tag.

17. The reader of claim 11, wherein the tag singulate module is singulate tags according to an EPC Gen 2 communications protocol.

18. The reader of claim 11, wherein the tag singulate module is configured singulate tags according to a binary traversal RFID communications protocol.

19. The reader of claim 11, wherein the tag singulate module is configured to singulate tags according to a slotted Aloha RFID communications protocol.

20. A method for a radio frequency identification (RFID) reader system, comprising:

(a) transmitting a radio frequency (RF) signal from a first reader to provide power to at least one tag;

(b) transmitting a first singulation command from the first reader;

(c) transmitting a second singulation command from a second reader;

(d) receiving an identification number from a tag powered by the RF signal at the first reader and the second reader in response to the first singulation command;

(e) transmitting a read verify command to the tag from the first reader after a delay time period;

(f) transmitting a read verify command to the tag from the second reader;

(g) receiving a response to the read verify command at the first reader; and

(h) verifying at the first reader that the response to the read verify command was received from the tag powered by the RF signal.

21. The method of claim 20, wherein step (h) comprises:

determining whether the identification number received from the tag in step (d) matches an identification number received in step (g).

22. The method of claim 21, further comprising:

(i) disregarding the tag if the identification number received from the tag in step (d) does not match the identification number received in step (g).

23. The method of claim 21, further comprising:

(i) accepting the tag if the identification number received from the tag in step (d) matches the identification number received in step (g).