MULTI-PROTOCOL RFID SYSTEM USING BIT-LOCK OR STEP-LOCK SYNCHRONIZATION

• US 20110279239A1
• Filed: 05/13/2011
• Published: 11/17/2011
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: Amtech Systems LLC (Roper Technologies, Inc.)
• Original Assignee: TC License Limited
• Inventors: Melville, Michael, Tiernay, Robert W., Catanach, Steven J., Gravelle, Kelly, Kao, Joseph H.
• Granted Patent: US 8,427,279 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 7/016 Synchronisation of sensing process
• CPC Class Codes: G06K 7/10039 interrogator driven, i.e. synchronous
• CPC Class Codes: G06K 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• CPC Class Codes: G06K 7/10297 arrangements for handling protocols designed for non-contact record carriers such as RFIDs NFCs, e.g. ISO/IEC 14443 and 18092 cryptographic protocols H04L9/00; network security protocols H04L63/00; real-time communication protocols in data switching networks H04L65/00; network protocols for data switching network services H04L67/00
• 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: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G
• CPC Class Codes: G08B 13/14 by lifting or attempted removal of hand-portable articles

Abstract

A multi-protocol RFID interrogating system employs a synchronization technique (step-lock) for a backscatter RFID system that allows simultaneous operation of closely spaced interrogators. The multi-protocol RFID interrogating system can communicate with backscatter transponders having different output protocols and with active transponders including: Title 21 compliant RFID backscatter transponders; IT2000 RFID backscatter transponders that provide an extended mode capability beyond Title 21; EGO™ RFID backscatter transponders, SEGO™ RFID backscatter transponders; ATA, ISO, ANSI AAR compliant RFID backscatter transponders; and IAG compliant active technology transponders. The system implements a step-lock operation, whereby adjacent interrogators are synchronized to ensure that all downlinks operate within the same time frame and all uplinks operate within the same time frame, to eliminate downlink on uplink interference.

Claims

1. ) An interrogator system to read active RFID transponders and to read backscatter RFID transponders comprising at least two transceivers, each transceiver covering a respective capture zone, the two capture zones being in proximity to each other, wherein said transceivers are adapted to use time division multiplexing to read the active RFID transponders in a first capture zone during a first time period, to then read the active RFID transponders in a second capture zone during a second time period and to simultaneously read the backscatter RFID transponders in both capture zones during a third time period.

2. ) The system of claim 1 wherein a synchronization signal is shared between said transceivers.

3. ) The system of claim 2 wherein the read of the backscatter RFID transponders in the third time period by each transceiver comprises a downlink transmission, the downlink transmission comprising plural bits, and wherein each bit of the backscatter downlink transmission of each transceiver occurs at substantially the same time.

4. ) The system of claim 1 wherein the active RFID transponders and the backscatter RFID transponders are read at different frequencies.

5. ) The system of claim 1 wherein the active RFID transponders that are read during the second time period use a different communications protocol from the active RFID transponders that are read during the first time period.

6. ) The system of claim 2 wherein during a fourth time period each transceiver transmits a downlink transmission to the active RFID transponders in its respective capture zone and wherein each bit of the active RFID transponder downlink transmission of each transceiver occurs at substantially the same time.

7. ) The system of claim 1 wherein the capture zones overlap.

8. ) The system of claim 1 wherein two or more active RFID transponders are read in turn during the first time period.

9. ) The system of claim 8 wherein the two or more active RFID transponders read in turn during the first time period are read using different communications protocols.

10. ) An interrogator system using at least a first and second protocol to read RFID transponders comprising:

at least two transceivers, each transceiver covering a respective capture zone, the respective capture zones being in proximity to each other; and

a synchronization circuit adapted to synchronize the two transceivers such that said at least two transceivers operate the first protocol simultaneously with each other during a first time period and operate the second protocol simultaneously with each other during a second and subsequent time period.

11. ) The system of claim 10 wherein each of said at least two transceivers transmits a respective downlink transmission as part of the first protocol, each downlink transmission comprising plural bits, with the first bit of each downlink transmission of each transceiver occurring at substantially the same time.

12. ) The system of claim 11 wherein the two protocols operate at different frequencies.

13. ) The system of claim 11 wherein a synchronization signal is shared between the transceivers.

14. ) The system of claim 13 wherein a first transceiver generates the synchronization signal and a second transceiver receives the synchronization signal.

15. ) The systems of claim 13 wherein one or more active RFID transponders are read during the first time period.

16. ) The system of claim 15 wherein two or more active RFID transponders are read in turn during the first time period.

17. ) The system of claim 16 wherein the two or more active RFID transponders read in turn during the first time period are read using different communications protocols.

18. ) The system of claim 15 wherein two or more active RFID transponders are read simultaneously.

19. ) The system of claim 15 wherein one or more backscatter RFID transponders are read in turn during the second time period.

20. ) The system of claim 19 wherein the two protocols operate at different frequencies.

21. ) An interrogator system for reading RFID transponders comprising:

at least two transceivers and a synchronization circuit, each of the at least two transceivers covering a respective capture zone and being arranged for transmitting a downlink signal in its respective capture zone, and each of the downlink signals comprising plural bits, wherein the respective capture zones overlap at least partially, creating an overlap capture zone in which an RFID transponder may be located, and wherein the synchronization circuit synchronizes the downlink signals from each of the two transceivers such that each bit in the downlink signals starts at substantially the same time.

22. ) The system of claim 21 wherein a synchronization signal is shared between the transceivers.

23. ) The system of claim 22 wherein a first transceiver generates the synchronization signal and a second transceiver receives the synchronization signal.

24. ) The systems of claim 21 wherein the RFID transponders are active RFID transponders.

25. ) The systems of claim 21 wherein the RFID transponders are backscatter RFID transponders.