Data processing system and method for accessing a plurality of radio frequency identification tags

• US 5,822,714 A
• Filed: 03/05/1997
• Issued: 10/13/1998
• Est. Priority Date: 03/05/1997
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cato, Robert Thomas
• Primary Examiner(s): Barlow, Jr., John E.
• Assistant Examiner(s): Bui, Bryan
• Application Number:
  US08/812,565
• Time in Patent Office: 587 Days
• Field of Search: 364/551.01, 364/517, 340/825.39-825.54, 340/572, 340/517, 340/568, 340/825.34, 342/42, 342/44, 342/51, 702/108, 235/435, 235/487
• US Class Current: 702/108
• 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 7/10039 interrogator driven, i.e. synchronous

Abstract

A data processing system and method are implemented for determining when a portion of RFID tags in a read volume cannot be fully accessed by a RFID tag reader. In the data processing system, multiple known RFID tags are placed around a perimeter of a three-dimensional read volume. A RFID tag reader interrogates each of the RFID tags to determine whether all the perimeter RFID tags can be accessed before the reader attempts to access the contents of the read volume. If the reader is unable to interrogate all of the perimeter RFID tags, then it is likely that a blockage of radio frequency signals within the read volume exists. Therefore, an RFID tag within the read volume cannot be accessed because the RF signals are unable to reach the RFID tag due to blockage. In this situation, a system operator would be alerted that an RFID reader is unable to accurately access a number of RFID tags within the read volume. The system operator would also be alerted as to a location of the blockage within the read volume. The system operator may then take appropriate action to rectify the RF signal blockage.

Claims

1. A radio frequency identification tag system, comprising:

a stand comprising a plurality of radio frequency identification tags, said radio frequency identification tags configured around a perimeter of a read volume, the stand being capable of supporting a plurality of objects, wherein each of the plurality of objects comprises an object identification tag.

2. The radio frequency identification tag system of claim 1 wherein the object identification tag is a radio frequency identification tag.

3. The radio frequency identification tag system of claim 1, further comprising:

a base station for accessing each of the plurality of radio frequency identification tags when each of the plurality of radio frequency identification tags is within a maximum read zone.

4. The radio frequency identification tag system of claim 3 wherein the base station accesses a first plurality of identification numbers from each of the plurality of radio frequency identification tags during an initial read operation.

5. The radio frequency identification tag system of claim 4 wherein the base station, comprises:

a memory for storing the plurality of identification numbers.

6. The radio frequency identification tag system of claim 4 wherein the base station accesses a second plurality of identification numbers from each of the plurality of radio frequency identification tags and compares the second plurality of identification numbers with the first plurality of identification numbers.

7. The radio frequency identification tag system of claim 6 wherein the base station indicates that a blockage exists when the second plurality of identification numbers is different than the first plurality of identification numbers.

8. The radio frequency identification tag system of claim 6 wherein the base station accesses the second plurality of identification numbers when the plurality of objects are placed within a read volume of the stand.

9. The radio frequency identification tag system of claim 8, wherein the plurality of radio frequency identification tags are physically mounted in a plurality of locations on the stand, wherein the initial read operation is performed by the base station previous to the plurality of objects being placed within the read volume of the stand, wherein the second plurality of identification numbers are accessed by the base station after the plurality of objects have been placed within the read volume of the stand, wherein the base station indicates that a blockage exists when the second plurality of identification numbers is different than the first plurality of identification numbers.

10. A method for operating a radio frequency identification tag system, comprising the steps of:

accessing a first plurality of identification numbers using an interrogator, the first plurality of identification numbers corresponding to a plurality of perimeter radio frequency identification tags configured around a read volume;

accessing a second plurality of identification numbers using the interrogator, the second plurality of identification numbers corresponding to the plurality of perimeter radio frequency identification tags configured around the read volume; and

comparing the second plurality of identification numbers and the first plurality of identification numbers to identify a blockage which prevents the interrogator from accessing each of a plurality of objects stored in the read volume.

11. The method of claim 10, further comprising the step of:

affixing the plurality of perimeter radio frequency identification tags to a stand.

12. The method of claim 11, wherein the step of affixing the plurality of perimeter radio frequency identification tags to the stand is performed before the step of accessing the first plurality of identification numbers, wherein the method further comprises the steps of:

placing a plurality of objects in the read volume, wherein each of the plurality of objects comprises an object radio frequency identification tag, before executing the step of accessing the second plurality of identification numbers using the interrogator; and

providing an indicator to an external user that a blockage exists when the second plurality of identification numbers differs from the first plurality of identification numbers.

13. The method of claim 10, further comprising the step of:

placing a plurality of objects in the read volume, wherein each of the plurality of objects comprises an object radio frequency identification tag, before executing a step of accessing the second plurality of identification numbers using the interrogator.

14. The method of claim 13, further comprising the step of:

accessing a third plurality of identification numbers corresponding to the plurality of objects in the read volume when the second plurality of identification numbers corresponds to the first plurality of identification numbers.

15. The method of claim 13, further comprising the step of:

providing an indicator to an external user that a blockage exists when the second plurality of identification numbers differs from the first plurality of identification numbers.

16. The method of claim 13, further comprising the step of:

disabling each of the plurality of perimeter radio frequency identification tags when the second plurality of identification numbers corresponds to the first plurality of identification numbers.

17. The method of claim 16, further comprising the step of:

accessing a third plurality of identification numbers corresponding to the plurality of objects in the read volume.

18. The method of claim 13, further comprising the step of:

indicating a location of a blockage when the second plurality of identification numbers differs from the first plurality of identification numbers.

19. A radio frequency identification tag system, comprising:

a plurality of perimeter radio frequency identification tags configured around a read volume;

an interrogator for accessing a first plurality of identification numbers corresponding to the plurality of perimeter radio frequency identification tags and for accessing a second plurality of identification numbers corresponding to the plurality of perimeter radio frequency identification tags; and

a base station for comparing the second plurality of identification numbers and the first plurality of identification numbers to identify a blockage which prevents the interrogator from accessing each of a plurality of objects stored in the read volume.

20. The radio frequency identification tag system of claim 19, further comprising:

a stand, wherein each of the plurality of perimeter radio frequency identification tags is configured about a perimeter of the stand.

21. The radio frequency identification tag system of claim 20, wherein the interrogator accesses the second plurality of identification numbers after the plurality of objects are placed in the read volume, wherein the base station indicates to an external user that a blockage exists when the second plurality of identification numbers differs from the first plurality of identification numbers.

22. The radio frequency identification tag system of claim 19 wherein the base station accesses the first plurality of identification numbers from each of the plurality of radio frequency identification tags during an initialization operation.

23. The radio frequency identification tag system of claim 19 wherein the base station indicates that a blockage exists when the second plurality of identification numbers is different than the first plurality of identification numbers.

24. The radio frequency identification tag system of claim 19 wherein the base station indicates a location of blockage when the second plurality of identification numbers is different than the first plurality of identification numbers.

25. The radio frequency identification tag system of claim 19 wherein the base station disables each of the plurality of radio frequency identification tags when the second plurality of identification numbers corresponds to the first plurality of identification numbers.

26. The radio frequency identification tag system of claim 19 wherein a plurality of objects are stored within the read volume before the interrogator accesses the second plurality of identification numbers.