Selective RF device activation

• US 20070018794A1
• Filed: 07/20/2005
• Published: 01/25/2007
• Est. Priority Date: 07/20/2005
• Status: Active Grant

• Current Assignee: Zest Labs, Inc.
• Original Assignee: Intelleflex Corporation
• Inventors: Paley, Daniel, Schlicht, Lauren, Bares, William
• Granted Patent: US 8,248,211 B2
• Time in Patent Office: Days
• US Class Current: 340/10.300
• CPC Class Codes: G06F 1/12 Synchronisation of different clock signals provided by a plurality of clock generators
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: G06K 19/0705 the battery being connected to a power saving arrangement
• CPC Class Codes: G06K 19/0707 the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation G06K19/0702 takes precedence
• CPC Class Codes: G06K 19/0712 the arrangement being capable of triggering distinct operating modes or functions dependent on the strength of an energy or interrogation field in the proximity of the record carrier active means for hindering electromagnetic reading or writing G06K19/07336
• 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
• 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: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: H04W 52/0238 where the received signal is an unwanted signal, e.g. interference or idle signal
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Systems and methods for activating one or more devices are disclosed. According to one embodiment, the device listens for an activate code, the activate code having a length field and a mask field, the mask field including a mask value, the length field specifying a length of the mask field to a final bit of the mask value. Upon receiving the activate code, the length field is compared to a stored length value for determining whether the length field meets a predefined criterion. If the length field meets the predefined criterion, an address of the activate value is loaded (if an address field is present) and the appropriate bits (mask value) of the mask field are compared to a stored activate value. An activate signal is generated if the mask value matches the stored activate value. The activate signal can be used to activate additional circuitry including the entire device.

Claims

1. A method for activating a device, comprising:

listening for an activate code;

receiving the activate code, the activate code having a length field and a mask field, the mask field including a mask value, the length field specifying a length of the mask field to a final bit of the mask value;

comparing the length field to a stored length value for determining whether the length field meets a predefined criterion;

comparing the mask value in the mask field to a stored activate value if the length field meets the predefined criterion; and

activating additional circuitry if the mask value matches the stored activate value.

2. A method as recited in claim 1, wherein the predefined criterion is that a value of the length field is greater than the stored length value.

3. A method as recited in claim 1, wherein the predefined criterion is that the length field matches the stored length value.

4. A method as recited in claim 1, wherein the predefined criterion is that the length field is not greater than the stored length value.

5. A method as recited in claim 1, wherein the mask value is not compared to the stored activate value if the length field does not meet the predefined criterion, wherein the additional circuitry is not activated.

6. A method as recited in claim 1, wherein the activate code further includes an address field, wherein the address field is received prior to the mask field, the address field indicating a start position of the mask value in the mask field of the activate command.

7. A method as recited in claim 6, wherein the mask field is of a predefined length, wherein the method fails if the length field and address field result in a roll-over when comparing the stored activate value to the mask value.

8. A method as recited in claim 6, wherein the mask field is a circular mask, wherein if the length field and address field result in a roll-over, the stored activate value is compared to bits in the mask field in a circular manner.

9. A method as recited in claim 1, wherein the device is a radio frequency identification (RFID) tag.

10. A method as recited in claim 9, wherein RFID tag is a passive tag.

11. A method as recited in claim 9, wherein RFID tag is an active tag.

12. A method as recited in claim 1, wherein the method is performed by several RFID tags, wherein only a portion of the tags compare the mask value in the mask field to a stored activate value upon receiving a particular activate code.

13. A Radio Frequency Identification (RFID) system, comprising:

a plurality of RFID tags performing the method of claim 1;

and

an RFID interrogator in communication with the RFID tags.

14. A method as recited in claim 1, wherein the activate code is preceded by an interrupt signal, and further comprising detecting the interrupt signal and performing the method of claim 1 upon detecting the interrupt signal.

15. A method as recited in claim 1, wherein the activate code is preceded by a clock synchronization signal.

16. A method as recited in claim 1, further comprising changing the stored length value for use in a subsequent communication.

17. A method as recited in claim 1, further comprising changing the stored activate value for use in a subsequent communication.

18. A method as recited in claim 1, wherein the mask value in the mask field is compared to the stored activate value on a bit-by-bit basis as the activate code is received.

19. A method as recited in claim 1, wherein the at least one of the fields of the activate code is programmable, wherein authorization is required prior to programming the at least one of the fields.

20. A method as recited in claim 19, wherein the authorization includes verification of a password.

21. A method for activating a device, comprising:

listening for an activate code;

receiving the activate code, the activate code having a length field and a mask field, the mask field including a mask value, the length field specifying a position of a final bit of the mask value;

comparing the mask value in the mask field to a stored activate value;

terminating the comparison upon comparing the final bit of the mask field as specified by the length field; and

activating additional circuitry if the mask value matches the stored activate value.

22. A method as recited in claim 21, further comprising comparing the length field to a stored length value for determining whether the length field meets a predefined criterion, wherein the additional circuitry is not activated if the length field fails to meet the predefined criterion.

23. A method as recited in claim 21, wherein the length field specifies at least one of (i) a length of a mask value in the mask field, (ii) a number of bits from a first bit following the length field to a final bit of the mask value, and (iii) a number of bits from a first bit of the mask field to the final bit of the mask value.

24. A method as recited in claim 21, wherein the activate code further includes an address field, wherein the address field is received prior to the mask field, the address field indicating a start position of the mask value in the mask field of the activate command.

25. A method as recited in claim 24, wherein the mask field is of a predefined length, wherein the method fails if the length field and address field result in a roll-over when comparing the stored activate value to the mask value.

26. A method as recited in claim 24, wherein the mask field is a circular mask, wherein if the length field and address field result in a roll-over, the stored activate value is compared to bits in the mask field in a circular manner.

27. A method as recited in claim 21, wherein the device is a radio frequency identification (RFID) tag.

28. A method as recited in claim 27, wherein RFID tag is a passive tag.

29. A method as recited in claim 27, wherein RFID tag is an active tag.

30. A method as recited in claim 21, wherein the method is performed by several RFID tags, wherein only a portion of the tags compare the mask value in the mask field to a stored activate value upon receiving a particular activate code.

31. A Radio Frequency Identification (RFID) system, comprising:

a plurality of RFID tags performing the method of claim 21;

and

an RFID interrogator in communication with the RFID tags.

32. A method as recited in claim 21, wherein the activate code is preceded by an interrupt signal, and further comprising detecting the interrupt signal and performing the method of claim 21 upon detecting the interrupt signal.

33. A method as recited in claim 21, wherein the activate code is preceded by a clock synchronization signal.

34. A method as recited in claim 21, further comprising changing the stored activate value for use in a subsequent communication.

35. A method as recited in claim 21, wherein the mask value in the mask field is compared to the stored activate value on a bit-by-bit basis as the activate code is received.

36. A method as recited in claim 21, wherein the at least one of the fields of the activate code is programmable, wherein authorization is required prior to programming the at least one of the fields.

37. A method as recited in claim 36, wherein the authorization includes verification of a password.

38. A method for selectively activating a subset of a plurality of devices, comprising transmitting an activate code having a length field and a mask field, wherein the length field dictates which of the plurality of devices process the mask field.

39. A method for selectively activating a subset of a plurality of devices, comprising transmitting several activate codes to a plurality of remote devices, wherein only a subset of the devices analyze a particular one of the activate codes based upon a variable size of the code.

40. A method as recited in claim 39, wherein whether the subset of the devices analyzes a particular one of the activate codes is further dependent upon a position of a mask field in the activate code.

41. A method for activating a device, comprising

receiving an activate code having an address field and a mask field, wherein the mask field has a mask value, wherein the address field indicates a start position of the mask value in the mask field, and

comparing the mask value to an activate value stored on the device.

42. A method as recited in claim 41, wherein the activate code further includes a length field, wherein the length field defines an end position of the mask value in the mask field.

43. A system comprising an interrogator and a plurality of devices in radio frequency communication with the interrogator, wherein a first subset of the devices are responsive to an activate command of a first length, wherein a second subset of the devices are responsive to an activate command of a second length.

44. A circuit for selectively generating an activate signal, comprising:

an interrupt circuit for determining whether an interrupt period of a received signal matches a predetermined plurality of values or falls within a predetermined range, the interrupt circuit outputting an interrupt signal if the interrupt period matches the predetermined value or falls within the predetermined range; and

a data comparison circuit for comparing a received activate code to a stored activate value, the activate code having a length field and a mask field, the length field specifying at least one of (i) a length of the mask field and (ii) a position of a final bit of a mask value of the mask field, the data comparison circuit generating an activate signal if the received mask value matches the stored activate value.

45. A circuit as recited in claim 44, wherein the activate code further includes an address field, and further comprising an address counter for receiving the address field, the address counter indicating a start position in the mask field of the activate command at which to begin comparing data in the mask field to the stored activate value.

46. A circuit for analyzing an activate code having a length field and a mask field, comprising:

a data register for storing an activate value;

a length counter for receiving the length field; and

a data comparison circuit for comparing at least a portion of the mask field to the activate value, the data comparison circuit generating an activate signal if the portion of the mask field matches the activate value.

47. A circuit as recited in claim 46, wherein the activate code further includes an address field, and further comprising an address counter for receiving the address field, the address counter indicating a start position in the mask field of the activate command at which to begin comparing data in the mask field to the activate value.

48. A method for analyzing an activate code having a length field and a mask field, the method comprising:

receiving the length field;

comparing the length field to a stored length value;

determining whether the length field meets a predefined criteria based on the comparison of the length field to the stored length value;

receiving the mask field, the mask field having a mask value;

comparing the mask value of the mask field to a stored activate value if the length field meets the predefined criteria; and

generating an activate signal if the received mask value matches the stored activate value.

49. A method as recited in claim 48, wherein the stored length value is a minimum permissible value of the length field, wherein the predefined criteria is that the length field define a value as large as or larger than the stored length value.

50. A method as recited in claim 48, further comprising ending the comparison of the mask value to the stored activate value based on the length field.

51. A method for analyzing an activate code having an address field and a mask field, the method comprising:

receiving the address field;

receiving the mask field, the mask field having a mask value, the address field indicating a location of the mask value in the mask field;

comparing the mask value of the mask field to a stored activate value; and

sending an activate signal if the received mask value matches the stored activate value.