RFID TAG POWER CONSERVATION SYSTEM AND METHOD

• US 20080218351A1
• Filed: 03/10/2008
• Published: 09/11/2008
• Est. Priority Date: 03/09/2007
• Status: Active Grant

• Current Assignee: Innovation Capital Law Group
• Original Assignee: Innovation Capital Law Group
• Inventors: Corrado, Anthony P., Logan, Rex T.
• Granted Patent: US 8,054,160 B2
• Time in Patent Office: Days
• US Class Current: 340/572.4
• CPC Class Codes: G06K 19/0705 the battery being connected to a power saving arrangement
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs

Abstract

Active multi-modal RFID tags, illuminator/tag/reader systems, circuit architecture and operational algorithms for battery power conservation that extends tag battery life from a typical 6 months to >5 years. The inventive system is particularly useful in asset and person tracking/inventory systems where power conservation is critical. The tag is configured with a micro-processor operational instruction set algorithm, modifiable on the fly via RF or IR, to synchronize a periodic tag awaken/sense envelope that overlaps the illuminator trigger pulse cycle and put the tag into deep, power conservation sleep for N periods of illuminator cycles. When the tag sees an illuminator signal with a different ID, or no illuminator signal at all, it transmits that anomaly via RF to a reader. This means the object or person with which the tag is associated has been moved out of the original illuminator field of view, permitting near real time investigation and tracking.

Claims

1. A method of conservation of battery power of an active, multi-modal RFID tag in a system having a device including illuminator and/or reader functionality, and where said device has only illuminator functionality, a second device having reader functionality, said tag being associated with an asset or person to be tracked and including a microprocessor, a memory device, a battery, an illuminator signal sensor receiver and a transmitter, said method comprising the steps of:

a) actuating said illuminator device to provide repeated cycles of output beacon trigger signal pulses of a first mode and of a selected duration within a field of view comprising a field of output coverage, said pulses having a fixed repeat period;

b) actuating said tag to wake up periodically to identify an illuminator trigger signal pulse of said first mode type;

c) determining the pulse cycle period of the identified illuminator trigger signal to create a periodic awaken/sense envelope for said tag comprising a tag awake period of sufficient duration to ensure it is awake to sense said identified illuminator trigger signal during at least a portion of said identified illuminator trigger signal pulse duration;

d) synchronizing said tag awaken/sense envelope to periodically overlap said identified illuminator trigger pulse cycle; and

e) actuating said tag to go into battery-conserving low power consumptive mode for N periods of said identified illuminator pulse cycles before re-awakening to sense and demodulate the entire IR signal to confirm identity of said illuminator trigger signal pulse whereby said battery life is extended from current life on the order of 6-months to on the order of several years.

2. A method of conservation of battery power as in claim 1 wherein said N periods have a time duration in the range of from about 5 to about 20 minutes.

3. A method of conservation of battery power as in claim 2 wherein said system is bi-modal, said modes being selected from RF, IR and Laser.

4. A method of conservation of battery power as in claim 3 wherein said modes are IR and RF, said illuminator trigger signal is IR, said tag sensor is an IR receiver, said tag includes an RF transmitter and said reader includes an RF receiver.

5. A method of conservation of battery power as in claim 1 wherein said illuminator trigger signal includes an illuminator ID by which said tag identifies said illuminator, and which includes the added steps of said tag saving in memory said ID as a first ID with which said tag is initially associated, said battery-conserving step e) is repeated if said tag, upon said re-awakening, senses and processes said trigger pulse to determine that said illuminator ID matches said first ID.

6. A method of conservation of battery power as in claim 5 wherein said tag communicates with said reader via said tag transmitter in a second mode of communication.

7. A method of conservation of battery power as in claim 5 which includes the added step of sending an anomaly signal to said reader when said tag determines that said illuminator ID does not match said first ID, or said tag does not sense an illuminator signal of said first mode type.

8. A method of conservation of battery power as in claim 7 which includes the step of awakening said tag periodically to provide just sufficient power for the tag receiver to sense the presence or not of a first mode signal from an illuminator without processing said illuminator trigger signal to determine the ID of the illuminator or the content of the signal, said sensing power awakening taking place during the N periods of deep sleep.

9. A method of conservation of battery power as in claim 8 which includes the step of continuing said periodic sensing-power-only awakening throughout said N periods cycle of deep sleep, and said tag awakens out of said deep sleep to sense and process said illuminator signal after said N periods cycle.

10. A method of conservation of battery power as in claim 9 which includes the alternative steps of:

where said illuminator signal processed after said N periods cycle matches said first ID said tag reverts to deep sleep; and

where said illuminator signal processed after said N periods cycle has a second ID that does not match said first ID and said anomaly signal is sent, said steps c), d) and e) are repeated for the illuminator having said second ID.

11. A method of conservation of battery power as in claim 5 wherein said no-signal detected anomaly signal is sent to said reader after said tag fails to sense a trigger signal after a preselected number of no-signal detection events during successive awakenings.

12. An improved microprocessor structure for a multi-modal RFID tag in a system having a device including illuminator and/or reader functionality, and where said device has only illuminator functionality, a second device having reader functionality, said tag being associated with an asset or person to be tracked and including a microprocessor, a memory device, a battery, an illuminator signal sensor receiver and a transmitter, said tag microprocessor having at least one operational instruction set comprising code structure:

a. to actuate said tag to wake up periodically to identify an illuminator trigger signal pulse of a first mode type;

b. to actuate said tag to determine the pulse cycle period of the identified illuminator trigger signal to create a periodic awaken/sense envelope for said tag comprising a tag awake period of sufficient duration to ensure it is awake to sense said identified illuminator trigger signal during at least a portion of said identified illuminator trigger signal pulse duration;

c. to actuate said tag to synchronize said tag awaken/sense envelope to periodically overlap said identified illuminator trigger pulse cycle; and

d. to actuate said tag to go into battery-conserving deep sleep for N periods of said identified illuminator pulse cycles before re-awakening to sense and confirm identity of said illuminator trigger signal pulse whereby said battery life is extended from current life on the order of 6-months to on the order of several years.

13. An improved microprocessor as in claim 12 wherein said code structure is configurable on the fly via a second communication mode between said tag and at least one of said reader and said illuminator.

14. An improved microprocessor as in claim 13 wherein said illuminator trigger signal includes an illuminator ID by which said tag identifies said illuminator, and said code structure actuates said tag to save said ID in said tag memory as a first ID with which said tag is initially associated, said code structure actuating said tag, upon said re-awakening, to sense and process said trigger pulse to determine that said illuminator ID matches said first ID and to re-enter said deep sleep mode when that condition is met.

15. An improved microprocessor as in claim 14 wherein said code structure actuates said tag to transmit via said transmitter in a second communication mode an anomaly signal to said reader when said tag determines that said illuminator ID does not match said first ID, or said tag does not sense an illuminator signal of said first mode type.

16. An improved microprocessor as in claim 15 wherein:

said code structure actuates said tag to awaken periodically to provide just sufficient power for the tag receiver to sense the presence or not of a first mode signal from an illuminator without processing said illuminator trigger signal to determine the ID of the illuminator or the content of the illuminator signal, said sensing power awakening taking place during the N periods of deep sleep;

said code structure actuates said tag to determine if the illuminator signal processed after said N periods cycle has a second ID that does not match said first ID, said anomaly signal is sent to said reader and said tag is actuated with respect to said second illuminator and its ID to determine that illuminator pulse cycle, to synchronize a tag sense/awaken envelope with respect thereto, and to enter a deep sleep with respect to N cycles of said second illuminator pulse cycles; and

said code structure actuates said tag to send a no-signal detected anomaly signal to said reader after said tag fails to sense a trigger signal after a preselected number of no-signal detection events during successive awakenings.

17. Active, battery powered multi-modal RFID tags for use in systems having a device including illuminator and/or reader functionality, and where said device has only illuminator functionality, a second device having reader functionality, said tag being associated with an asset or person to be tracked comprising in operative combination:

a) a circuit including elements of a receiver for receiving at least one signal from a device having illuminator functionality including a first mode signal transmitter selected from IR, RF, US and Laser communication signals, a microprocessor for processing said signals and having tag operational instruction set code, a receiver for receiving said first mode illuminator communication signals, a memory, a battery, and a transmitter for transmitting second mode communication signals selected from IR, RF, US and Laser to a device having reader functionality with a receiver capable of receiving said second mode communication signals from said tag; and

b) said microprocessor having at least one operational instruction set comprising code structure;

i) to actuate said tag to wake up periodically to identify an illuminator trigger signal pulse of said first mode type;

ii) to actuate said tag to determine the pulse cycle period of the identified illuminator trigger signal to create a periodic awaken/sense envelope for said tag comprising a tag awake period of sufficient duration to ensure it is awake to sense said identified illuminator trigger signal during at least a portion of said identified illuminator trigger signal pulse duration;

iii) to actuate said tag to synchronize said tag awaken/sense envelope to periodically overlap said identified illuminator trigger pulse cycle; and

iv) to actuate said tag to go into battery-conserving deep sleep for N periods of said identified illuminator pulse cycles before re-awakening to sense and confirm identity of said illuminator trigger signal pulse whereby said battery life is extended from current life on the order of 6-months to on the order of several years.

18. Active, battery powered multi-modal RFID tag as in claim 17 wherein said illuminator trigger signal includes an illuminator ID by which said tag identifies said illuminator, and said code structure actuates said tag to save said ID in said tag memory as a first ID with which said tag is initially associated, said code structure actuating said tag, upon said re-awakening, to sense and process said trigger pulse to determine that said illuminator ID matches said first ID and to re-enter said deep sleep mode when that condition is met.

19. Active, battery powered multi-modal RFID tag as in claim 18 wherein said code structure actuates said tag to transmit via said tag transmitter in a second communication mode an anomaly signal to said reader device when said tag determines that said illuminator ID does not match said first ID, or said tag does not sense an illuminator signal of said first mode type.

20. Active, battery powered multi-modal RFID tag as in claim 19 wherein said code structure actuates said tag to awaken periodically to provide just sufficient power for the tag receiver to sense the presence or not of a first mode signal from an illuminator without processing said illuminator trigger signal to determine the ID of the illuminator or the content of the illuminator signal, said sensing power awakening taking place during the N periods of deep sleep;

said code structure actuates said tag to determine if the illuminator signal processed after said N periods cycle has a second ID that does not match said first ID, said anomaly signal is sent to said reader and said tag is actuated with respect to said second illuminator and its ID to determine that illuminator pulse cycle, to synchronize a tag sense/awaken envelope with respect thereto, and to enter a deep sleep with respect to N cycles of said second illuminator pulse cycles; and

said code structure actuates said tag to send a no-signal detected anomaly signal to said reader after said tag fails to sense a trigger signal after a preselected number of no-signal detection events during successive awakenings.