Apparatus for recognizing radio frequency identification (RFID) and method thereof, and data processing method of RFID

• US 8,395,481 B2
• Filed: 06/30/2006
• Issued: 03/12/2013
• Est. Priority Date: 03/23/2006
• Status: Active Grant

• Current Assignee: KT Corporation
• Original Assignee: KT Corporation
• Inventors: Kim, Yeon-Soo
• Primary Examiner(s): Mehmood, Jennifer
• Assistant Examiner(s): Mahase, Pameshanand
• Application Number:
  US12/294,041
• Publication Number:
  US 20090115582A1
• Time in Patent Office: 2,447 Days
• Field of Search: 340/3.41
• 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

Abstract

The present invention relates to an RFID reader and a method thereof, and an RFID data processing method. The RFID reader generates a specific query message to a plurality of RFIDs, receives a first response message corresponding to the query message from at least one RFID among the RFIDs, and sequentially identifies a tag ID of a collided RFID by using a collision solving message when a collision occurs according to the result of receiving a first response message. The RFID reader can quickly and accurately identify a plurality of RFIDs since it can eliminate an unnecessary time such as excessive no response slot generation or repeated rounds through a sequential identification process for the collided RFIDs.

Claims

1. A method for reading a radio frequency identification (RFID) by an RFID reader reading a plurality of RFIDs, the method comprising:

a) generating a specific query message to the RFIDs;

b) receiving a first response message corresponding to the query message from at least one RFID among the RFIDs, wherein the RFIDs receive the specific query message including round size information from the RFID reader and randomly select a slot number based on the round size information of the specific query message; and

c) sequentially identifying a tag ID of the collided RFID by using a collision solving message when collision is generated according to the result of receiving the first response.

2. The method of claim 1, wherein c) comprises:

c-1) generating a first collision solving message including a preset discrimination code to the RFIDs;

c-2) receiving a second response message corresponding to the first collision solving message from at least at least one RFID among the RFIDs; and

c-3) identifying a tag ID based on the second response message when no collision is generated according to the result of receiving the second response message.

3. The method of claim 2, wherein when a collision is generated according to the result of receiving the second response message in c-3), the method comprises:

i) changing the first discrimination code;

ii) generating a second collision solving message including the changed first discrimination code to the RFIDs;

iii) receiving a third response message corresponding to the second collision solving message from at least one RFID among the RFIDs;

iv) receiving a fourth response message that is not collided from an RFID among the RFIDs by repeating iv) to the vi) when a collision is generated according to the result of receiving the third response message; and

v) identifying the tag ID based on the fourth response message.

4. The method of claim 3, wherein i) comprises:

storing the first discrimination code as a first test code; and

adding a specific bit to the most significant bit (MSB) among the bits of the first discrimination code to change the first discrimination code.

5. The method of claim 4, wherein iv) comprises:

when no collision is generated according to the result of receiving the third response message,

generating a second discrimination code based on the first test code;

generating a third collision solving message to the RFIDs based on the second discrimination code;

receiving a fifth response message based on the third collision solving message from at least one RFID among the RFIDs; and

identifying a tag ID based on the fifth response message when no collision is generated according to the result of receiving the fifth response message.

6. The method of claim 5, comprising:

when a collision is generated according to the result of receiving the fifth response message,

1) changing the second discrimination code;

2) generating a fourth collision solving message including the changed second discrimination code to the RFIDs;

3) receiving a sixth response message corresponding to the fourth collision solving message from at least one RFID among the RFIDs;

4) receiving a seventh response message that is not collided from at least one RFID among the RFIDs by repeating

     1) to

     3) when a collision is generated according to the result of receiving the sixth response message; and

5) identifying the tag ID based on the seventh response message.

7. The method of claim 6, wherein the step of changing the second discrimination code comprises adding a specific bit to the MSB of the bits of the second discrimination code and changing the second discrimination code.

8. The method of claim 6, wherein when no collision is generated according to the result of receiving the sixth response message, the method comprises identifying a tag ID based on the sixth response message.

9. The method of claim 1, wherein when no collision is generated according to the result of receiving the response message in c), the method comprises:

i) identifying a tag ID based on the first response message;

ii) generating a temporary identifier based on the identified tag ID;

iii) generating a re-query message including the temporary identifier to the RFID;

iv) receiving a second response message based on the re-query message from the RFID;

v) determining a collision state of the received the second response message; and

vi) sequentially detecting a tag ID of the collided RFID when a collision is generated according to the collision state determination.

10. The method of claim 9, wherein the temporary identifier includes at least 16 bits among the bits of the identified tag ID.

11. A method for processing data by a radio frequency identification (RFID) transmitting/receiving data with an RFID reader reading a tag ID, the method comprising:

a) receiving a query message including round size information from the RFID reader;

b) randomly selecting a slot number based on the round size information of the query message;

c) generating a first response message including a stored tag ID when the slot number satisfies a specific value; and

d) transmitting the first response message to the RFID reader.

12. The method of claim 11, wherein c) comprises storing the slot number and standing by when the slot number does not satisfy the specific value.

13. The method of claim 12, further comprising, after d):

receiving a re-query message including a first temporary identifier from the RFID reader;

comparing the first temporary identifier and the stored tag ID and determining a matched state;

reducing the slot number by a predetermined number when they are not matched according to the result of determining the matching state; and

generating a second response message including the tag ID when the reduced slot number satisfies a specific value.

14. The method of claim 12, wherein iv) comprises storing the reduced slot number and standing by when the reduced slot number does not satisfy a specific value.

15. The method of claim 12, further comprising, after iv):

receiving a collision solving message including a discrimination code from the RFID reader;

determining whether the discrimination code corresponds to a second temporary identifier generated based on the tag ID; and

generating a third response message including the tag ID to the RFID reader when they correspond to each other.

16. The method of claim 12, further comprising standing by for receiving of data when the discrimination code does not correspond to the second temporary identifier.

17. The method of claim 13, wherein the second temporary identifier includes at least 16 bits among the bits of the tag ID.

18. A radio frequency identification (RFID) reader for reading a plurality of RFIDs, comprising:

a communicator for transmitting/receiving data to/from the RFID through RF signals;

a storage unit for storing predetermined round size information, and storing tag IDs included by the RFIDs and product information matched with the tag IDs; and

a controller for controlling the communicator and the storage unit, providing the round size information to the RFIDs, and sequentially identifying the tag IDs of the RFIDs by using a collision solving message when a collision is generated for a specific message received from the RFIDs, wherein the RFIDs randomly select a slot number based on the round size information.

19. The RFID reader of claim 18, wherein the controller comprises:

a collision state determining module for determining a collision state for the specific message received from the RFIDs;

a code managing module including a first storing module for storing a discrimination code and a second storing module for storing a test code, and changing the discrimination code and the test code stored in the first storing module and the second storing module according to a specific control;

a tag identifying module for detecting the tag ID based on the specific message received from the RFIDs, and generating a temporary identifier based on the detected tag ID; and

a control module for controlling the collision state determining module, the code managing module, and the tag identifying module, generating a collision solving message including the discrimination code based on the collision state of the collision state determining module, and transmitting the collision solving message to the RFIDs through the communicator.

20. The RFID reader of claim 19, wherein the control module generates a specific message including the temporary identifier or the round size information to the RFIDs so as to detect the tag ID of the RFIDs.

21. The RFID reader of claim 19, wherein the discrimination code includes at least one bit, a specific bit value is added to the discrimination code based on the MSB among the bit according to a control by the control module, or the discrimination code is updated based on the test code.

22. The RFID reader of claim 21, wherein the test code is generated based on the MSB among the bit included by the discrimination code according to a control by the control module.

23. The RFID reader of claim 19, wherein the temporary identifier includes 16 bits among the bits of the detected tag ID.

24. The RFID reader of claim 19, wherein the second storing module has a first input last output (FILO) structure.

25. A method for reading a radio frequency identification (RFID) by an RFID reader reading a plurality of RFIDs, the method comprising:

a) requesting a tag ID from the RFID;

b) receiving a first response message from the RFID, wherein the RFID receive a specific query message including round size information from the RFID reader and randomly select a slot number based on the round size information of the specific query message;

c) generating a collision solving message including the stored discrimination code of 0 to the RFID when a collision is generated according to the received result;

d) receiving a second response message corresponding to the collision solving message from the RFID;

e) checking whether the MSB of the discrimination code is 1 when a collision is generated according to the result of receiving the second response message;

f) adding a bit of 0 to the MSB of the discrimination code and changing it into a first discrimination code when the MSB is not 1 according to the result of checking the MSB; and

g) generating a collision solving message including the first discrimination code to the RFID and repeating the steps after d).

26. The method of claim 25, wherein f) comprises:

adding a bit of 1 to the MSB of the discrimination code to generate a first test code when the MSB is checked to be 1 according to the result of checking the MSB;

storing the generated first test code;

adding a bit of 0 to the MSB of the discrimination code to change it into a second discrimination code; and

generating a collision solving message including the second discrimination code to the RFID, and performing the steps after d).

27. The method of claim 25, wherein e) comprises:

e-1) checking whether the MSB of the stored discrimination code is 1 when no collision is generated at the received second response message;

e-2) checking whether there is a stored test code when the MSB is 1 according to the result of checking the MSB;

e-3) generating a third discrimination code based on the stored test code when the stored test code is found according to the result of checking the test code; and

e-4) generating a collision solving message including the third discrimination code to the RFIDs, and performing the steps after d).

28. The method of claim 27, wherein e-2) comprises:

when the MSB is not 1 according to the result of checking the MSB,

generating a fourth discrimination code by changing the MSB of the discrimination code into the binary number of 1; and

generating a collision solving message including the fourth discrimination code to the RFIDs, and performing the steps after d).

29. The method of claim 27, further comprising terminating the steps when the test code is not stored according to the result of checking the test code.

30. The method of claim 25, further comprising:

before a), resetting the discrimination code and the test code; and

setting the discrimination code to be 0.