RFID INTERROGATOR RETRANSMITTING COMMAND DEPENDING ON COLLISION SITUATION AND CONTROL METHOD THEREOF

• US 20110006885A1
• Filed: 03/12/2009
• Published: 01/13/2011
• Est. Priority Date: 03/12/2008
• Status: Active Grant

• Current Assignee: CISC Semiconductor Design+Consulting GmbH, Electronics and Telecommunications Research Institute
• Original Assignee: CISC Semiconductor Design+Consulting GmbH, Electronics and Telecommunications Research Institute
• Inventors: Choi, Gilyoung, Tschische, David, Chae, Jongsuk, Oh, Sewon, Preishuber-Pfluegl, Josef, Park, Chanwon, Pyo, Cheolsig
• Granted Patent: US 8,779,899 B2
• Time in Patent Office: Days
• US Class Current: 340/10.3
• 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 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

As an RFID interrogator transmitting a command depending on a collision situation and a control method thereof, the RFID interrogator includes a collision diagnosis unit that analyzes data of a received signal received during a receive time in correspondence with a transmitted signal from an RF communication unit that can transmit and receive signal to and from one or more tag, verifies whether or not a collision occurs in the received signal, and diagnoses a collision type depending on an analysis result of the data of the received signal; and a collision resolution unit that can retransmit a command to the tag through the RF communication unit depending on the collision situation on the basis of whether or not occurrence of the collision or not and the collision type that are received from the collision diagnosis unit.

Claims

1. An RFID interrogator retransmitting command depending on a collision situation, comprising:

a collision diagnosis unit that analyzes data of a received signal received during a receive time in correspondence with a transmitted signal from an RF communication unit that can transmit and receive signal to and from one or more tag, verifies whether or not a collision occurs in the received signal, and diagnoses a collision type depending on an analysis result of the data of the received signal; and

a collision resolution unit that can retransmit a command depending on the collision situation to the tag through the RF communication unit on the basis of the occurrence of the collision and the collision type that are received from the collision diagnosis unit,

wherein the collision resolution unit includes a situational command retransmission portion that determines whether or not the command is retransmitted on the basis of the occurrence of the collision and the collision type and a random wait time calculation portion that calculates a random wait time for retransmitting the command.

2. The RFID interrogator according to claim 1, wherein the collision type diagnosed by the collision diagnosis unit includes a tag on tag collision, a multiple interrogators to interrogator collision, and an interrogator to interrogator collision.

3. The RFID interrogator according to claim 1, wherein the collision resolution unit retransmits the command in the case in which the received collision type is the multiple interrogators to tag collision or the interrogator to interrogator collision.

4. The RFID interrogator according to claim 3, wherein the collision resolution unit retransmits the command after suspension as long as the random wait time calculated by the random wait time calculation portion when determining that the tag is not separated.

5. The RFID interrogator according to claim 3, wherein the collision resolution unit retransmits the command without suspension as long as the random wait time when determining that the tag is separated into a current response slot.

6. The RFID interrogator according to claim 3, wherein the collision resolution unit performs an anti-collision without retransmitting the command when determining that the maximum number of transmission times is reached.

7. The RFID interrogator according to claim 1, wherein the collision resolution unit retransmits the command in the case in which a receiver timeout occurs.

8. The RFID interrogator according to claim 7, wherein the collision resolution unit retransmits the command when the receiver timeout occurs and it is determined that the tag is separated into the current response slot.

9. The RFID interrogator according to claim 7, wherein the collision resolution unit retransmits the command only once when the receiver timeout occurs.

10. The RFID interrogator according to claim 7, wherein it is determined that the receiver timeout occurs in the case in which a tag response is not received within a predetermined time after transmitting the command.

11. A control method of an RFID interrogator including a collision diagnosis unit and a collision resolution unit, which retransmits a command depending on a collision situation, comprising:

a collision diagnosis step of allowing the collision diagnosis unit to analyze data of a received signal received during a receive time in correspondence with a transmitted signal from an RF communication unit, verify whether or not a collision occurs in the received signal, and diagnose a collision type depending on an analysis result of the data of the received signal; and

a collision resolution step of allowing the collision resolution unit to retransmit a command depending on the collision situation to a tag through an RF communication unit on the basis of the occurrence of the collision or not and the collision type,

wherein the collision resolution step includes a situational command retransmission step of determining whether or not the command is retransmitted on the basis of the occurrence of the collision and the collision type and a random wait time calculation step of calculating a random wait time for retransmitting the command.

12. The control method of an RFID interrogator according to claim 11, wherein the collision type diagnosed at the collision diagnosis step includes a tag on tag collision, a multiple interrogators to tag collision, and an interrogator to interrogator collision.

13. The control method of an RFID interrogator according to claim 11, wherein at the collision resolution step, the command is retransmitted in the case in which the collision type is the multiple interrogators to tag collision or the interrogator to interrogator collision.

14. The control method of an RFID interrogator according to claim 13, wherein at the collision resolution step, the command is retransmitted after suspension as long as the random wait time calculated at the random wait time calculation step when it is determined that the tag is not separated.

15. The control method of an RFID interrogator according to claim 13, wherein at the collision resolution step, the command is retransmitted without suspension as long as the random wait time when it is determined that the tag is separated into a current response slot.

16. The control method of an RFID interrogator according to claim 13, wherein at the collision resolution step, an anti-collision step is performed without retransmitting the command when it is determined that the maximum number of retransmission times is reached.

17. The control method of an RFID interrogator according to claim 11, wherein at the collision resolution step, the command is retransmitted in the case in which a receiver timeout occurs.

18. The control method of an RFID interrogator according to claim 17, wherein at the collision resolution step, the command is retransmitted when the receiver timeout occurs and it is determined that the tag is separated into the current response slot.

19. The control method of an RFID interrogator according to claim 17, wherein at the collision resolution step, the command is retransmitted only once when the receiver timeout occurs.

20. The control method of an RFID interrogator according to claim 17, wherein it is determined that the receiver timeout occurs when a tag response is not received within a predetermined time after the command is transmitted.