Systems and Methods for Q Value Determination

• US 20080111664A1
• Filed: 11/13/2006
• Published: 05/15/2008
• Est. Priority Date: 11/13/2006
• Status: Active Grant

• Current Assignee: Novanta Corporation (Novanta Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Maguire, Yael
• Granted Patent: US 8,081,063 B2
• Time in Patent Office: Days
• US Class Current: 340/10.4
• 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

Abstract

Systems and methods for determining a Q value are shown and described. The method can include determining at least one of: a number of empty slots, a number of collided slots, and a number of singly occupied slots, in response to the completion of an inventory round and applying a function to at least one of: the number of empty slots, the number collided slots, and the number of singly occupied slots, to determine a Q value for another inventory round.

Claims

1. A method of determining a Q value for use by a radio frequency identification (RFID) tag reader in an inventory round, the inventory round classifying each slot of the inventory round as either an empty slot, a collided slot, or singly occupied slot, the method comprising:

(a) determining at least one of;

a number of empty slots, a number of collided slots, and a number of singly occupied slots, in response to the completion of an inventory round; and

(b) applying a function to at least one of;

the number of empty slots, the number collided slots, and the number of singly occupied slots, to determine a Q value for another inventory round.

2. The method of claim 1 wherein applying a function comprises applying a logarithm function to at least one of:

the number of empty slots, the number of collided slots, and the number of singly occupied slots.

3. The method of claim 2 wherein the logarithm function comprises a base 2 logarithm function.

4. The method of claim 1 wherein applying a function comprises applying a base 2 logarithm function to the sum of the number of a multiple of singly occupied slots and a multiple of the number of collided slots.

5. The method of claim 4 wherein the multiple of the number of collided slots is two.

6. The method of claim 4 wherein the multiple of the number of singly occupied slots is one.

7. The method of claim 1 wherein applying a function comprises using a series to estimate a logarithm of at least one of:

the number of empty slots, the number collided slots, and the number of singly occupied slots.

8. A system for determining a Q value for use by a radio frequency identification (RFID) tag reader in an inventory round, the inventory round classifying each slot of the inventory round as either an empty slot, a collided slot, or singly occupied slot, the system comprising:

a transmitter that transmits, to zero or more RFID tags, a message during a slot of an inventory round;

a receiver that receives a response from at least one of the zero or more RFID tags; and

a processing unit that determines at least one of;

a number of empty slots, a number of collided slots, and a number of singly occupied slots, in response to the completion of an inventory round and applies a function to at least one of;

the number of empty slots, the number collided slots, and the number of singly occupied slots, to determine a Q value for another inventory round.

9. The system of claim 8 wherein the processing unit comprises a digital signal processor.

10. The system of claim 8 wherein the processing unit comprises a field programmable gate array.

11. The system of claim 8 wherein the processing unit comprises an application specific integrated circuit.

12. The system of claim 8 wherein the processing unit comprises a microprocessor.

13. The system of claim 8 wherein the processing unit applies a logarithm function to at least one of:

the number of empty slots, the number of collided slots, and the number of singly occupied slots.

14. The system of claim 13 wherein the logarithm function comprises a base-2 logarithm function.

15. The system of claim 8 wherein the processing unit applies a base-2 logarithm function to the sum of the number of a multiple of singly occupied slots and a multiple of the number of collided slots.

16. The system of claim 15 wherein the multiple of the number of collided slots is two.

17. The system of claim 15 wherein the multiple of the number of singly occupied slots is one.

18. The method of claim 8 wherein the processing unit uses a series to estimate a logarithm of at least one of:

the number of empty slots, the number collided slots, and the number of singly occupied slots.

19. A system for determining a Q value for use by a radio frequency identification (RFID) tag reader in an inventory round, the inventory round classifying each slot of the inventory round as either an empty slot, a collided slot, or singly occupied slot, the system comprising:

means for determining at least one of;

a number of empty slots, a number of collided slots, and a number of singly occupied slots, in response to the completion of an inventory round; and

means for applying a function to at least one of;

the number of empty slots, the number collided slots, and the number of singly occupied slots, to determine a Q value for another inventory round.

20. The system of claim 19 wherein the means for applying a function comprises means for applying a logarithm function to at least one of:

the number of empty slots, the number of collided slots, and the number of singly occupied slots.

21. The system of claim 20 wherein the logarithm function comprises a base 2 logarithm function.

22. The system of claim 19 wherein the means for applying a function comprises means for applying a base 2 logarithm function to the sum of the number of a multiple of singly occupied slots and a multiple of the number of collided slots.

23. The system of claim 22 wherein the multiple of the number of collided slots is two.

24. The system of claim 22 wherein the multiple of the number of singly occupied slots is one.

25. The system of claim 19 wherein the means applying a function comprises means for using a series to estimate a logarithm of at least one of:

the number of empty slots, the number collided slots, and the number of singly occupied slots.