RFID READER DEVICE HAVING A READ-ONLY MODE, AND RELATED OPERATING METHODS

• US 20120119883A1
• Filed: 11/16/2010
• Published: 05/17/2012
• Est. Priority Date: 11/16/2010
• Status: Abandoned Application

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: BEKRITSKY, BENJAMIN J.
• Application Number:
  US12/947,408
• Publication Number:
  US 20120119883A1
• Time in Patent Office: Days
• US Class Current: 340/10.4
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• 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

Abstract

A method of operating a radio frequency identification (RFID) reader device is presented. The method begins by operating the RFID reader device in a read-only mode, during which the RFID reader device does not generate tag interrogation signals. The method continues by receiving a tag response signal generated from an RFID tag being interrogated by an interrogator device that is distinct and separate from the RFID reader device. The tag response signal is received by the RFID reader device while it is operating in the read-only mode. The method continues by determining a location of the RFID tag, wherein the location is determined based at least in part on information associated with the received tag response signal.

Claims

1. A method of operating a radio frequency identification (RFID) reader device, the method comprising:

operating the RFID reader device in a read-only mode;

receiving a tag response signal generated from an RFID tag being interrogated by an interrogator device that is distinct and separate from the RFID reader device, wherein receiving the tag response signal is performed by the RFID reader device while it is operating in the read-only mode; and

determining a location of the RFID tag, wherein the location is determined based at least in part on information associated with the received tag response signal.

2. The method of claim 1, further comprising correlating the received tag response signal with the interrogator device.

3. The method of claim 1, further comprising determining a distance between the RFID tag and the RFID reader device, wherein the distance is determined based at least in part on the information associated with the received tag response signal.

4. The method of claim 1, wherein the interrogator device interrogates the RFID tag with an interrogation signal;

and the location is determined based at least in part on a phase difference between the interrogation signal and the received tag response signal.

5. The method of claim 1, wherein the location is determined based at least in part on signal strength of the received tag response signal.

6. The method of claim 1, further comprising:

maintaining the RFID reader device in a low power sleep mode;

detecting, with the RFID reader device, an interrogation signal generated by the interrogator device; and

switching the RFID reader device from the low power sleep mode to the read-only mode in response to detecting the interrogation signal, wherein receiving the tag response signal is performed while the RFID reader device is in the read-only mode.

7. The method of claim 6, further comprising:

maintaining the RFID reader device in the read-only mode;

detecting, with the RFID reader device, loss of the interrogation signal; and

switching the RFID reader device from the read-only mode to the low power sleep mode in response to detecting loss of the interrogation signal.

8. The method of claim 6, wherein the interrogator device interrogates the RFID tag with the interrogation signal.

9. The method of claim 1, further comprising receiving the tag response signal at a second RFID reader device that is distinct and separate from both the interrogator device and the RFID reader device, wherein:

receiving the tag response signal at the second RFID reader device occurs concurrently with receiving the tag response signal at the RFID reader device; and

the location of the RFID tag is determined based at least in part on information associated with the tag response signal as received at the RFID reader device, and information associated with the tag response signal as received at the second RFID reader device.

10. The method of claim 9, further comprising receiving the tag response signal at the interrogator device, wherein:

receiving the tag response signal at the interrogator device occurs concurrently with receiving the tag response signal at the RFID reader device and concurrently with receiving the tag response signal at the second RFID reader device; and

the location of the RFID tag is determined based at least in part on information associated with the tag response signal as received at the RFID reader device, information associated with the tag response signal as received at the second RFID reader device, and information associated with the tag response signal as received at the interrogator device.

11. The method of claim 9, further comprising operating the second RFID reader device as a read-only RFID reader device, wherein receiving the tag response signal at the second RFID reader device occurs while operating the second RFID reader device as a read-only RFID reader device.

12. A radio frequency identification (RFID) reader device comprising:

an RFID radio module configured to support both an interrogate-and-read mode and a read-only mode; and

a processor operatively associated with the RFID radio module to control switching between the interrogate-and-read mode and the read-only mode,

wherein, while operating in the read-only mode, the RFID radio module receives a tag response signal generated by an RFID tag being interrogated by an interrogator device other than the RFID reader device.

13. The RFID reader device of claim 12, wherein the interrogator device is physically distinct, separate, and remote from the RFID reader device.

14. The RFID reader device of claim 12, wherein:

the processor maintains the RFID reader device in a low power sleep mode during periods of inactivity;

the RFID radio module detects an interrogation signal generated by the interrogator device; and

the processor switches the RFID reader device from the low power sleep mode to the read-only mode in response to detecting the interrogation signal.

15. The RFID reader device of claim 14, wherein:

during operation of the RFID reader device in the read-only mode, the RFID radio module detects loss of the interrogation signal; and

the processor switches the RFID reader device from the read-only mode to the low power sleep mode in response to detecting loss of the interrogation signal.

16. A method of operating a radio frequency identification (RFID) system having an interrogator device and a read-only RFID reader device, the method comprising:

transmitting an interrogation signal from the interrogator device; and

concurrently receiving, at both the interrogator device and the read-only RFID reader device, a tag response signal generated by an RFID tag in response to the interrogation signal.

17. The method of claim 16, further comprising:

analyzing the tag response signal as received at the interrogator device to determine a first distance between the RFID tag and the interrogator device;

analyzing the tag response signal as received at the read-only RFID reader device to determine a second distance between the RFID tag and the read-only RFID reader device; and

determining a location of the RFID tag based at least in part on the first distance and the second distance.

18. The method of claim 16, further comprising:

maintaining the read-only RFID reader device in a low power sleep mode;

detecting the interrogation signal with the read-only RFID reader device while the read-only RFID reader device is operating in the low power sleep mode; and

switching the read-only RFID reader device from the low power sleep mode to the read-only mode in response to detecting the interrogation signal, wherein receiving the tag response signal at the read-only RFID reader device is performed while the read-only RFID reader device is in the read-only mode.

19. The method of claim 18, further comprising:

during operation of the read-only RFID reader device in the read-only mode, detecting loss of the interrogation signal; and

switching the read-only RFID reader device from the read-only mode to the low power sleep mode in response to detecting loss of the interrogation signal.

20. The method of claim 16, wherein:

the RFID system includes a second read-only RFID reader device; and

the tag response signal is concurrently received at the interrogator device, the read-only RFID reader device, and the second read-only RFID reader device.

21. The method of claim 20, further comprising:

analyzing the tag response signal as received at the interrogator device to determine a first distance between the RFID tag and the interrogator device;

analyzing the tag response signal as received at the read-only RFID reader device to determine a second distance between the RFID tag and the read-only RFID reader device;

analyzing the tag response signal as received at the second read-only RFID reader device to determine a third distance between the RFID tag and the second read-only RFID reader device; and

determining a location of the RFID tag based at least in part on the first distance, the second distance, and the third distance.