Method and system for correctly identifying specific RFID tags

• US 9,449,205 B2
• Filed: 12/19/2014
• Issued: 09/20/2016
• Est. Priority Date: 07/22/2010
• Status: Active Grant

• Current Assignee: Vocollect, Inc. (Honeywell International Inc.)
• Original Assignee: Vocollect, Inc. (Honeywell International Inc.)
• Inventors: Vargo, Rob, Zoschg, Ryan, Borgoyn, Edward Charles, Naughton, Mike
• Primary Examiner(s): BEE, ANDREW W.
• Application Number:
  US14/577,037
• Publication Number:
  US 20150102913A1
• Time in Patent Office: 641 Days
• US Class Current: 1/1
• 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
• 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 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G06K 7/10128 the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device
• 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: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders

Abstract

A system and method for identifying a specific RFID tag includes RFID reader circuitry, such as within an RFID reader, configured for sending and receiving RF signals to detect RFID tags and for obtaining signal parameter information associated with the RFID tags. Processing circuitry is configured for using the signal parameter information for one or more tags of the RFID tags and calculating a tag score for the one or more RFID tags. The processing circuitry is further configured for determining a specific RFID tag using the tag scores for the one or more RFID tags.

Claims

1. A method for identifying a specific RFID tag, the method comprising:

sending and receiving RF signals, using an RFID reader, to detect RFID tags and obtain signal parameter information associated with the RFID tags;

determining a received signal strength indication (RSSI) value for each of the RFID tags;

determining an occurrence frequency value for each of the RFID tags;

calculating a tag score for each of the RFID tags using both the RSSI value and occurrence frequency value for the respective RFID tags;

determining a difference between a highest tag score of the calculated tag scores for the RFID tags and a next highest tag score of the calculated tag scores for the RFID tags; and

comparing the difference with a first threshold value; and

identifying the RFID tag having the highest tag score as the specific RFID tag in response to the difference being greater than the first threshold value.

2. The method of claim 1 further comprising selecting the RFID tag associated with the highest tag score as the specific RFID tag.

3. The method of claim 1 further comprising normalizing the RSSI value and occurrence frequency value by dividing the RSSI value by the maximum detected RSSI value, and by dividing the occurrence frequency value by the maximum detected occurrence frequency value.

4. The method of claim 1 further comprising assigning a different weight to at least one signal parameter value of the signal parameter information over another signal parameter value in the calculation of the tag scores by multiplying the at least one signal parameter value by a respective multiplier.

5. A system for identifying a specific RFID tag, the system comprising:

RFID reader circuitry that sends and receives RF signals to detect RFID tags and that obtains signal parameter information associated with the RFID tags;

wherein the signal parameter information includes a received signal strength indication (RSSI) value and an occurrence frequency value for one or more of the RFID tags;

processing circuitry that uses the RSSI values and occurrence frequency values for the one or more RFID tags and weights at least one signal parameter value of the signal parameter information for the one or more tags of the RFID tags to calculate tag scores for the one or more of the RFID tags.

6. The system of claim 5 further comprising an RFID reader containing the RFID reader circuitry and a computer device containing the processing circuitry.

7. The system of claim 5 wherein the processing circuitry averages the RSSI and occurrence frequency values for each of the one or more RFID tags to calculate a tag score for each of the one or more RFID tags.

8. The system of claim 5 wherein the processing circuitry determines a difference between a highest tag score and a next highest tag score for the one or more RFID tags and compares the difference to a first threshold value to identify the specific RFID tag using the tag scores.

9. The system of claim 8 wherein the RFID reader circuitry and the processing circuitry are contained in a single device.

10. The system of claim 8 wherein when the difference does not exceed the first threshold value, to again obtain signal parameter information associated with the RFID tags and to calculate another tag score for the one or more of the RFID tags and to determine a difference between a highest another tag score and a next highest another tag score and to compare the difference between the highest another tag score and the next highest another tag score to the first threshold value to identify the specific RFID tag using the another tag scores.

11. The system of claim 10, wherein when the difference between the another tag scores again does not exceed the first threshold value, the processing circuitry:

averages the tag score and the another tag score for each of the one or more RFID tags to determine an average score for each of the one or more RFID tags;

determines a difference between the highest average score and the second highest average score;

compares the difference between the highest average score and the second highest average score to a second threshold value; and

selects the RFID tag associated with the highest average score as the specific RFID tag based upon if the difference between the highest average score and the second highest average score exceeds the second threshold value.

12. The system of claim 11 wherein the processing circuitry is further operable, if the difference between the highest average score and the second highest average score exceeds the second threshold value, to determine if the highest average score is greater than a minimum average score threshold.

13. The system of claim 5 wherein the processing circuitry normalizes the RSSI values and occurrence frequency values by dividing each RSSI value by a maximum detected RSSI value, and normalizing the occurrence frequency values by dividing each occurrence frequency value by the maximum detected occurrence frequency value.

14. The system of claim 5 wherein the at least one RSSI value and occurrence frequency value is normalized before emphasizing the value with a respective multiplier value.

15. A system for identifying a specific RFID tag, the system comprising:

RFID reader circuitry that sends and receives RF signals to detect RFID tags and that obtains signal parameter information associated with the RFID tags;

processing circuitry that uses the signal parameter information for one or more tags of the RFID tags and weights at least one signal parameter value of the signal parameter information for the one or more tags of the RFID tags to calculate tag scores for the one or more RFID tags, wherein the tag scores are used to identify the specific RFID tag.

16. The system of claim 15 wherein the RFID reader circuitry and the processing circuitry are contained in separate devices.

17. The system of claim 15, wherein the RFID reader circuitry obtains signal parameter values including a received signal strength indication (RSSI) value and an occurrence frequency value for the one or more RFID tags and the processor circuitry is operable for using RSSI values and occurrence frequency values to calculate tag scores for the one or more tags of the RFID tags.

18. The system of claim 17 wherein the processing circuitry averages the RSSI and occurrence frequency values for each of the one or more RFID tags to calculate a tag score for each of the one or more RFID tags.

19. The system of claim 17 wherein the processing circuitry normalizes the RSSI values and occurrence frequency values by dividing the RSSI value by a maximum detected RSSI value, and normalizing the occurrence frequency value by dividing the occurrence frequency value by the maximum detected occurrence frequency value.

20. The system of claim 15 wherein the processing circuitry determines a difference between a highest tag score and a next highest tag score for the one or more RFID tags and compares the difference to a first threshold value to identify the specific RFID tag using the tag scores.