Arrangement for and method of optimally adjusting the scan rate of scan beams generated bya radio frequency identification (RFID) tag reader having an array of antennas

• US 9,465,963 B2
• Filed: 10/11/2013
• Issued: 10/11/2016
• Est. Priority Date: 10/11/2013
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Inventors: Griesmann, Daniel S, Ekl, Randy L, Jain, Binit
• Primary Examiner(s): Bugg, George
• Assistant Examiner(s): Akhter, Sharmin
• Application Number:
  US14/051,979
• Publication Number:
  US 20150102908A1
• Time in Patent Office: 1,096 Days
• Field of Search: 340 101- 106
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10198 setting parameters for the interrogator, e.g. programming parameters and operating modes
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22

Abstract

Retail items movable from an inventory location at a retail venue through a portal to a retail exit are automatically tracked. The items are individually associated with radio frequency identification (RFID) tags. An RFID tag reader has an array of antennas for generating a multitude of scan beams at an adjustable scan rate. A first set of the beams covers the inventory location, and a second set of the beams covers the portal to determine an exit characteristic of the items that have exited the retail venue. A point-of-sale workstation at the retail venue is operative, independently of the tag reader, for determining a sold characteristic of the items that have been sold. A controller dynamically adjusts the scan rate of the first and second sets of scan beams to an optimal scan rate as a function of the determined exit and sold characteristics.

Claims

1. An arrangement for automatically tracking items movable through a portal, the items being located at an inventory location and being individually associated with radio frequency identification (RFID) tags, the arrangement comprising:

an RFID tag reader having an array of antennas for generating a multitude of scan beams at an adjustable scan rate, a first set of the beams covering the inventory location to scan and interrogate the tags of items located in the inventory location, and a second set of the beams covering the portal to scan and interrogate the tags of items passing through the portal to determine an exit characteristic of the items that have passed through the portal;

a workstation operative, independently of the RFID tag reader, for determining a moved characteristic of the items that have been moved; and

a controller operatively connected to the RFID tag reader and the workstation, for optimally dynamically adjusting the scan rate of the first and second sets of scan beams that are scanning the inventory location and the portal to an optimal scan rate as a function of the determined exit characteristic and the determined moved characteristic.

2. The arrangement of claim 1, wherein the exit and moved characteristics are respectively descriptive of exit and moved quantities;

wherein the controller is operative for increasing the scan rate of the second set of the beams, and for concomitantly decreasing the scan rate of the first set of the beams, when the exit quantity is less than the moved quantity by a predetermined proportion.

3. The arrangement of claim 2, wherein the controller is operative for decreasing the scan rate of the second set of the beams, and for concomitantly increasing the scan rate of the first set of the beams, when the exit quantity is not less than the moved quantity by the predetermined proportion.

4. The arrangement of claim 1, wherein the controller is operative for periodically and incrementally adjusting the scan rate by predetermined amounts until the optimal scan rate has been reached.

5. The arrangement of claim 1, wherein the controller is operative for adjusting the scan rate by varying the number of the scan beams until the optimal scan rate has been reached.

6. The arrangement of claim 1, wherein the RFID tag reader has a minimum scan rate limit and a maximum scan rate limit, and wherein the controller is operative for adjusting the scan rate to not exceed the scan rate limits.

7. The arrangement of claim 1, wherein the workstation is a point-of-sale station having a reader for counting how many of the items that have been moved have been sold.

8. The arrangement of claim 1, wherein the RFID tag reader is mounted at an overhead location at a retail venue having an exit that serves as the portal.

9. The arrangement of claim 1, wherein the RFID tag reader is mounted at a location at a venue having a passage that serves as the portal and through which the items are moved to another inventory location.

10. The arrangement of claim 1, wherein the first and the second sets of beams have at least one beam in common.

11. A method of automatically tracking items movable through a portal, the items being located at an inventory location and being individually associated with radio frequency identification (RFID) tags, the method comprising:

generating a multitude of scan beams at an adjustable scan rate with an array of antennas of an RFID tag reader;

scanning and interrogating the tags of items located in the inventory location with a first set of the beams covering the inventory location;

scanning and interrogating the tags of items passing through the portal with a second set of the beams covering the portal to determine an exit characteristic of the items that have passed through the portal;

determining, independently of operation of the RFID tag reader, a moved characteristic of the items that have been moved; and

optimally dynamically adjusting the scan rate of the first and second sets of scan beams that are scanning the inventory location and the portal to an optimal scan rate as a function of the determined exit characteristic and the determined moved characteristic.

12. The method of claim 11, wherein the exit and moved characteristics are respectively descriptive of exit and moved quantities;

wherein the adjusting is performed by increasing the scan rate of the second set of the beams, and by concomitantly decreasing the scan rate of the first set of the beams, when the exit quantity is less than the moved quantity by a predetermined proportion.

13. The method of claim 12, wherein the adjusting is performed by decreasing the scan rate of the second set of the beams, and by concomitantly increasing the scan rate of the first set of the beams, when the exit quantity is not less than the moved quantity by the predetermined proportion.

14. The method of claim 11, wherein the adjusting is performed by periodically and incrementally adjusting the scan rate by predetermined amounts until the optimal scan rate has been reached.

15. The method of claim 11, wherein the adjusting is performed by varying the number of the scan beams until the optimal scan rate has been reached.

16. The method of claim 11, wherein the RFID tag reader has a minimum scan rate limit and a maximum scan rate limit, and wherein the adjusting is performed by adjusting the scan rate to not exceed the scan rate limits.

17. The method of claim 11, and counting how many of the items that have been moved have been sold.

18. The method of claim 11, and mounting the RFID tag reader at an overhead location at a retail venue having an exit that serves as the portal.

19. The method of claim 11, and mounting the RFID tag reader at a location at a venue having a passage that serves as the portal and through which the items are moved to another inventory location.