Method and apparatus for power management for a radio frequency identification system

• US 20080231449A1
• Filed: 03/20/2007
• Published: 09/25/2008
• Est. Priority Date: 03/20/2007
• Status: Active Grant

• Current Assignee: Golba LLC
• Original Assignee: Radiofy, LLC
• Inventors: Moshfeghi, Mehran
• Granted Patent: US 8,305,190 B2
• Time in Patent Office: Days
• US Class Current: 340/572.1
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G06K 7/00 Methods or arrangements for sensing record carriers, e.g. for reading patterns methods or arrangements for marking the record carrier in digital fashion G06K1/00; pattern recognition G06F18/00; arrangements for image or video recognition or understanding G06V10/00; character recognition, recognising digital ink or document-oriented image-based pattern recognition G06V30/00
• CPC Class Codes: G06K 7/10207 parameter settings related to power consumption of the interrogator
• CPC Class Codes: G08C 17/02 using a radio link

Abstract

A method and device of power management for a networked radio frequency identification (“RFID”) system are disclosed. The described power management methods reduce the power consumption of battery-operated RFID readers and RFID tags. These power conservation methods increase the RFID system'"'"'s hours of operation and decrease the cost by allowing the RFID readers and tags to function for a longer period of time before requiring charging or replacement of their batteries.

Claims

1. A radio frequency identification (“

RFID”

) system comprising;

an RFID tag having a memory and an antenna;

an RFID reader logically coupled to said RFID tag and configured to communicate to said RFID tag, wherein said RFID reader includes;

a power management unit configured to provide energy conserving command for conserving power in response to ambient information from surrounding environment;

a digital processing controller coupled to said power management unit and configured to control communications between said RFID tag and said RFID reader; and

an interface unit coupled to said digital processing controller, wherein said interface unit is capable of entering a sleep state for conserving power in response to said energy conserving command.

2. The system of claim 1, further comprising:

a router logically coupled to said RFID reader and configured to route information for said RFID reader over a network; and

a server coupled to said router and configured to process said information.

3. The system of claim 2, wherein said RFID reader further includes:

a power switching unit coupled to said digital processing controller and configured to switch said interface unit from an active state to a sleep state in response to said energy conserving command;

a baseband circuitry coupled to said digital processing controller and configured to facilitate communication between said RFID tag and said RFID reader; and

a memory unit coupled to said digital processing controller and configured to store data for restoring said interface unit after said interface wakes up from said sleep state.

4. The system of claim 1, wherein said power management unit includes a global positioning system (“

GPS”

) to determine real-time physical location of said RFID reader.

5. The system of claim 4, wherein said power management unit is capable of identifying a power efficient location for transmission in response to GPS data received from said GPS.

6. The system of claim 5, wherein said power efficient location includes a location with less RF interference signals.

7. The system of claim 1, wherein said interface unit is a display.

8. The system of claim 7, wherein said power management unit includes a motion sensor to obtain said ambient information.

9. The system of claim 1, wherein said power management unit includes a power control tag, which is capable of waking up said RFID reader in response to a control tag signal received from an external device.

10. The system of claim 1, wherein said power management unit includes an activating circuitry for waking up said RFID reader.

11. The system of claim 1, wherein said power management unit is capable of adjusting transmitting frequency to conserve power consumption.

12. The system of claim 1, wherein said power management unit is capable of transmitting information via a power-aware wireless ad-hoc networking method to conserve power.

13. The system of claim 1, wherein said digital processing controller is capable of entering into a sleep state in response to said ambient information.

14. The system of claim 1, wherein said power management unit is capable of providing power management to RFID tags.

15. A method for transmitting information relating to radio frequency identification (“

RFID”

) in an RFID reader, comprising;

obtaining location information from a global positioning system (“

GPS”

);

calculating a current location of said RFID reader according to said location information;

retrieving a plurality of active RF reading zones relating to said current location of said RFID reader from a storage location of said RFID reader;

determining whether said current location of said RFID reader is within said at least one zone of said plurality of active RF reading zones; and

switching at least a portion of components of said RFID reader into a sleep state to conserve power if said current location of said RFID reader is outside of any of said plurality of active RF reading zones.

16. The method of claim 15, further comprising:

activating at least a portion of components of said RFID reader from said sleep state to an active state if said current location of said RFID reader is within said at least one of said plurality of active RF reading zones.

17. The method of claim 15, wherein said determining whether said current location of said RFID reader is within at least one zone of said plurality of active RF reading zones further includes:

identifying power efficient reading zones from said plurality of active RF reading zones according to said location information; and

comparing said current location of said RFID reader with at least one of said power efficient reading zones.

18. The method of claim 15, wherein said determining whether said current location of said RFID reader is within at least one active of said RF reading zone further includes identifying a reading zone with minimal interference in response to said location information.

19. A method for transmitting information relating to radio frequency identification (“

RFID”

) in an RFID system, comprising;

activating a motion sensor in an RFID reader for sensing movement of said RFID reader;

obtaining motion information from said motion sensor;

retrieving predetermined standard moving information from a memory unit of said RFID reader;

comparing said motion information with said predetermined standard moving information to identify whether said RFID reader is moving;

providing a still signal if result of comparison between said motion information and said predetermined standard moving information indicates that said RFID reader is still; and

switching at least a portion of said RFID reader to a sleep state for conserving power in response to said still signal.

20. The method of claim 19, further comprising:

providing a moving signal if said result of comparison between said motion information and said predetermined standard moving information indicates that said RFID reader is in motion; and

switching at least a portion of said RFID reader from said sleep state to an active state in response to said moving signal.

21. The method of claim 19, wherein said switching at least a portion of said RFID reader to said sleep state for conserving power further includes maintaining a wake-up circuitry active.

22. The method of claim 21, wherein said maintaining a wake-up circuit active further includes:

switching a digital processing controller of said RFID reader to said sleep state;

turning a display of said RFID reader to said sleep state;

switching an RF transmission unit of said RFID reader to said sleep state; and

reducing clock frequency for saving power.

23. A method for transmitting information relating to radio frequency identification (“

RFID”

) in an RFID system, comprising;

activating a battery power sensor to monitor battery level of an RFID reader;

acknowledging a low battery power signal from said battery power sensor when said battery level reaches a predefined level;

activating a power conserving procedure in response to said low battery power signal; and

filtering redundant tag reads and incomplete tag reads to conserve power before data transmission.

24. The method for claim 23, further comprising:

informing an access point regarding low battery situation with said RFID reader; and

the reader using Ad-hoc/mesh networking for conserving power.

25. The method for claim 23, further comprising:

informing an access point regarding low battery situation with said RFID reader; and

adjusting transmitting and receiving transmission frequency for conserving power.

26. The method for claim 23, further comprising:

informing an access point regarding low battery situation with said RFID reader; and

utilizing signal boosters to transmit and receive signals for increasing signal range, reducing cost, and conserving power.

27. The method for claim 23, further comprising:

grouping data transmissions from a plurality of tag data reads over a period of time into a group data transmission; and

transmitting said group data transmission to an access point.

28. A method for transmitting information relating to radio frequency identification (“

RFID”

) in an RFID system, comprising;

identifying a first tag to be read;

transmitting a first transmission power to read said first tag;

transmitting a second transmission power which is higher frequency than said first transmission power to read said first tag if said first transmission power fails to read said first tag; and

storing said second transmission power together with an identification of said first tag in a memory unit of an RFID reader for subsequent reads if said second transmission power reads said first tag correctly.

29. The method of claim 28, further comprising:

identifying a second tag to be read;

transmitting a third transmission power to read said second tag;

transmitting a fourth transmission power which is higher than said third transmission power to read said second tag if said third transmission power fails to read said second tag; and

storing said fourth transmission power together with an identification of said second tag of said memory unit in said RFID reader for subsequent reads if said fourth transmission power reads said second tag correctly.

30. The method of claim 28, further comprising:

adjusting the electronic beam-offset and beam-width angles to focus the beam energy more directly on a targeted tag.

storing said beam-offset angle and beam-width angle together with an identification of said tag.

31. An apparatus for transmitting information relating to radio frequency identification (“

RFID”

) in an RFID reader, comprising;

means for obtaining location information from a global positioning system (“

GPS”

);

means for calculating a current location of said RFID reader according to said location information;

means for retrieving a plurality of active RF reading zones relating to said current location of said RFID reader from a storage location of said RFID reader;

means for determining whether said current location of said RFID reader is within said at least one zone of said plurality of active RF reading zones; and

means for switching at least a portion of components of said RFID reader into a sleep state to converse power if said current location of said RFID reader is outside of any of said plurality of active RF reading zones.

32. The apparatus of claim 31, further comprising:

means for activating at least a portion of components of said RFID reader from said sleep state to an active state if said current location of said RFID reader is within said at least one of said plurality of active RF reading zones.

33. The apparatus of claim 31, wherein said means for determining whether said current location of said RFID reader is within said at least one zone of said plurality of active RF reading zones further includes:

means for identifying power efficient reading zones from said plurality of active RF reading zones according to said location information; and

means for comparing said current location of said RFID reader with at least one of said power efficient reading zones.

34. The apparatus of claim 31, wherein said means for determining whether said current location of said RFID reader is within said at least one active RF reading zone further includes means for identifying a reading zone with minimal interference in response to said location information.

35. An apparatus for transmitting information relating to radio frequency identification (“

RFID”

) in an RFID system, comprising;

means for activating a motion sensor in an RFID reader for sensing movement of said RFID reader;

means for obtaining motion information from said motion sensor;

means for retrieving predetermined standard moving information from a memory unit of said RFID reader;

means for comparing said motion information with said predetermined standard moving information to identify whether said RFID reader is moving;

means for providing a still signal if result of comparison between said motion information and said predetermined standard moving information indicates that said RFID reader is still; and

means for switching at least a portion of said RFID reader to a sleep state for conserving power in response to said still signal.

36. The apparatus of claim 35, further comprising:

means for providing a moving signal if said result of comparison between said motion information and said predetermined standard moving information indicates that said RFID reader is in motion; and

means for switching at least a portion of said RFID reader from said sleep state to an active state in response to said moving signal.

37. The apparatus of claim 35, wherein said means for switching at least a portion of said RFID reader to said sleep state for conserving power further includes means for maintaining a wake-up circuitry active.

38. The apparatus of claim 37, wherein said means for maintaining a wake-up circuit active further includes:

means for switching a digital processing controller of said RFID reader to said sleep state;

means for turning a display of said RFID reader to said sleep state;

means for switching an RF transmission unit of said RFID reader to said sleep state; and

means for reducing clock frequency for saving power.

39. A radio frequency identification (“

RFID”

) system comprising;

an RFID reader having a memory and an antenna;

an RFID tag, logically coupled to said RFID reader, having a power management unit configured to provide an energy conserving command for conserving power in response to activity of said RFID tag.

40. The system of claim 39, further comprising:

a router logically coupled to said RFID tag and configured to route information from said RFID tag to a network; and

a server coupled to said router and configured to process said information.

41. The system of claim 39, further comprising:

signal boosters to transmit and receive signals for increasing signal range, reducing cost, and conserving power.

42. The system of claim 39, further comprising:

the RFID tag using Ad-hoc/mesh networking to conserve power.

43. The system of claim 40, wherein said power management unit is capable of adjusting transmitting frequency to conserve power consumption.

44. The system of claim 39, wherein said power management unit is capable of adjusting said RFID tag'"'"'s circuit clock frequency to conserve power when said activity of said RFID tag is low.

45. The system of claim 39, wherein said power management unit is capable of putting a portion of circuitry of said RFID tag into a sleep state when said activity of said RFID tag is low.

46. The system of claim 39, wherein said power management unit is capable of monitoring battery power of said RFID tag.