Wireless identification systems and protocols

• US 20030030568A1
• Filed: 06/14/2002
• Published: 02/13/2003
• Est. Priority Date: 06/14/2001
• Status: Active Grant

• Current Assignee: RF Code Incorporated
• Original Assignee: RF Code Incorporated
• Inventors: Lastinger, Roc, Rodgers, James, Fowler, William, Freiwald, Dean
• Granted Patent: US 7,030,731 B2
• Time in Patent Office: Days
• US Class Current: 340/825.49
• 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 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G06K 7/10297 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: G07C 9/28 the pass enabling tracking or indicating presence

Abstract

Monitoring systems and protocols are disclosed that are flexible in mode operation and format depending on the environment in which they are used. Such monitoring systems and protocols are able to change their utilization automatically, or by received instruction to do so. A location detection system includes one or more low frequency transmitters, one or more radio frequency monitoring tags and one or more receiving devices. The low frequency transmitter transmits location identification information, such as the transmitter ID, to a tag in the vicinity of the transmission. The tag relays the transmitter ID using a higher frequency transmission sent from the tag to the receiver. Communication protocols are disclosed that enable deciphering of multiple tag transmissions starting simultaneously.

Claims

1. In a system for monitoring location of tags, a method performed by a tag for transmitting a tag message, the method comprising:

determining whether the tag has been moved since an immediately prior tag message transmission; and

if it is determined that the tag has been moved, then beginning transmitting the tag message without awaiting lapse of an intermessage gap;

otherwise, beginning transmitting the tag message after lapse of the intermessage gap.

2. The method of claim 1 wherein the tag message comprises indicia of whether the tag has been moved since an immediately prior tag message transmission.

32. The system of claim 1 wherein the monitor includes a record for each locator, the record associating a respective physical location of a particular locator and a respective identity of the particular locator

33. The system of claim 1 wherein a tag of the plurality receives a plurality of locator messages in a time period, each locator message being associated with a respective received signal strength, and the tag transmits, in response to the plurality of locator messages, a tag message in accordance with a particular locator message, of the plurality of locator messages, having the largest magnitude received signal strength.

34. The system of claim 1 wherein the tag receives a plurality of locator messages in a time period, each locator message being associated with a respective received signal strength, and the tag transmits a tag message corresponding to each received locator message.

35. The system of claim 1 wherein:

a particular tag of the plurality transmits according to a beacon rate; and

the particular tag transmits a tag message in accordance with a most recently received locator message.

36. The system of claim 1 wherein:

at least one of the monitor and a locator of the plurality transmits a query; and

a tag of the plurality transmits a tag message in response to receiving the query.

37. The system of claim 1 wherein:

operation of a particular tag of the plurality includes a plurality of modes comprising a first mode wherein transmitting is according to a beacon rate, each transmitted tag message in accordance with a respective most recently received locator message, and a second mode wherein transmitting is in response to receiving a query; and

the particular tag selects a mode of operation from the plurality of modes in accordance with a command.

38. The system of claim 37 wherein a locator of the plurality transmits the command.

39. The system of claim 37 wherein the monitor transmits the command.

40. The system of claim 37 wherein the particular tag determines a beacon rate in accordance with the command.

41. The system of claim 37 wherein:

the particular tag comprises a motion detector; and

the particular tag determines the beacon rate in response to the motion detector.

42. The system of claim 37 wherein the particular tag comprises:

a power supply circuit; and

a circuit selectively coupled to the power supply circuit in response to receiving the command.

3. In a system for monitoring location of tags, the system comprising at least two of a monitor, a locator, and a tag, a method performed by at least one of the monitor, the locator, and the tag for transmitting a message, the message comprising a first group of slots and a second group of slots, the method comprising:

transmitting a start of message signal;

selecting a series of slots, for signaling an assertion in each slot of the series, such that selected slots of the series are separated in time by more than a minimum number of slots;

transmitting a signal in the first group of slots to convey the series in a progressive order; and

transmitting a signal in the second group of slots to convey the series in regressive order.

6. The method of claim 3, 4, or 5 wherein the first group of slots consists of a total number of slots and the second group of slots consists of the total number of slots.

7. The method of claim 3, 4, or 5 wherein:

the message comprises a plurality of words, each word comprising a respective first group of slots; and

a first word of the plurality of words comprises indicia of the number of slots of the first group of slots in a subsequent word of the plurality of words.

8. The method of claim 3, 4, or 5 wherein the message comprises indicia for identifying within the first group of slots a plurality of subparts.

9. The method of claim 3, 4, or 5 wherein:

each group of slots comprises a plurality of subparts, each subpart for conveying a respective series; and

selecting, and transmitting are accomplished with respect to each series so that the first group of slots conveys each respective series and the second group of slots conveys the respective series.

10. The method of claim 3, 4, or 5 wherein:

each group of slots comprises a plurality of subparts, each subpart for conveying a respective series;

selecting, and transmitting are accomplished with respect to each series so that the first group of slots conveys each respective series and the second group of slots conveys the respective series; and

the plurality of subparts conveys location identification information.

11. The method of claim 3, 4, or 5 wherein the message comprises location identification information and a command.

12. The method of claim 3, 4, or 5 performed by at least one of the locator and the monitor, wherein the message comprises a command to be performed by the tag.

13. The method of claim 3, 4, or 5 performed by at least one of the locator and the monitor, wherein the message conveys a command to be performed by the tag to alter a beacon rate of the tag in accordance with the command.

14. The method of claim 3, 4, or 5 performed by at least one of the locator and the monitor, wherein the message conveys a command to be performed by the tag to activate a mode of operation of the tag from a set of modes comprising a beaconing mode and an interrogated mode.

15. The method of claim 3, 4, or 5 wherein assertion comprises a code comprising a plurality of bits.

4. In a system for monitoring location of tags, the system comprising at least two of a monitor, a locator, and a tag, a method performed by at least one of the monitor, the locator, and the tag for transmitting a message, the message comprising a first group of slots and a second group of slots, the method comprising:

transmitting a start of message signal;

selecting a series of slots, such that selected slots of the series are separated in time by more than a minimum number of slots;

transmitting a signal in the first group of slots to convey an assertion in each of the slots of the series; and

transmitting a signal in the second group of slots to convey an assertion in each of the slots that is not in the series.

5. In a system for monitoring location of tags, the system comprising at least two of a monitor, a locator, and a tag, a method performed by at least one of the monitor, the locator, and the tag for transmitting a message, the message comprising a first group of slots and a second group of slots, the method comprising:

transmitting a start of message signal;

selecting a series of slots, such that selected slots of the series are separated in time by more than a minimum number of slots;

transmitting a signal in the first group of slots to convey an assertion in each of the slots of the series, and to convey the series in a progressive order; and

transmitting a signal in the second group of slots to convey an assertion in each of the slots not in the series, and to convey the series in regressive order.

16. A tag for use in a system for monitoring location of tags, the tag comprising:

means for determining whether the tag has been moved since an immediately prior tag message transmission; and

means operative, if it is determined that the tag has been moved, for beginning transmitting the tag message without awaiting lapse of an intermessage gap; and

means operative, otherwise, for beginning transmitting the tag message after lapse of the intermessage gap.

17. The tag of claim 16 wherein the tag message comprises indicia of whether the tag has been moved since an immediately prior tag message transmission.

18. A system for monitoring location of tags, the system comprising a monitor, a plurality of locators, and a plurality of tags, communication from a sender, being at least one of the monitor, a particular locator, and a particular tag, comprising a message that includes a first group of slots and a second group of slots, the sender comprising:

means for transmitting a start of message signal;

means for selecting a series of slots, for signaling an assertion in each slot of the series, such that selected slots of the series are separated in time by more than a minimum number of slots;

means for transmitting a signal in the first group of slots to convey the series in a progressive order; and

means for transmitting a signal in the second group of slots to convey the series in regressive order.

21. The system of claim 18, 19, or 20 wherein the first group of slots consists of a total number of slots and the second group of slots consists of the total number of slots.

22. The system of claim 18, 19, or 20 wherein:

the message comprises a plurality of words, each word comprising a respective first group of slots; and

a first word of the plurality of words comprises indicia of the number of slots of the first group of slots in a subsequent word of the plurality of words.

23. The system of claim 18, 19, or 20 wherein the message comprises indicia for identifying within the first group of slots a plurality of subparts.

24. The system of claim 18, 19, or 20 wherein:

each group of slots comprises a plurality of subparts, each subpart for conveying a respective series; and

the means for selecting and each means for transmitting operate with respect to each series so that the first group of slots conveys each respective series and the second group of slots conveys the respective series.

25. The system of claim 18, 19, or 20 wherein:

each group of slots comprises a plurality of subparts, each subpart for conveying a respective series;

the means for selecting and each means for transmitting operate with respect to each series so that the first group of slots conveys each respective series and the second group of slots conveys the respective series; and

the plurality of subparts conveys location identification information.

26. The system of claim 18, 19, or 20 wherein the message comprises location identification information and a command.

27. The system of claim 18, 19, or 20 wherein the message comprises a command to be performed by the tag.

28. The system of claim 18, 19, or 20 wherein the message conveys a command to be performed by the tag to alter a beacon rate of the tag in accordance with the command.

29. The system of claim 18, 19, or 20 wherein the message conveys a command to be performed by the tag to activate a mode of operation of the tag from a set of modes comprising a beaconing mode and an interrogated mode.

30. The system of claim 18, 19, or 20 wherein assertion comprises a code comprising a plurality of bits.

19. A system for monitoring location of tags, the system comprising a monitor, a plurality of locators, and a plurality of tags, communication from a sender, being at least one of the monitor, a particular locator, and a particular tag, comprising a message that includes a first group of slots and a second group of slots, the sender comprising:

means for transmitting a start of message signal;

means for selecting a series of slots, such that selected slots of the series are separated in time by more than a minimum number of slots;

means for transmitting a signal in the first group of slots to convey an assertion in each of the slots of the series; and

means for transmitting a signal in the second group of slots to convey an assertion in each of the slots that is not in the series.

20. A system for monitoring location of tags, the system comprising a monitor, a plurality of locators, and a plurality of tags, communication from a sender, being at least one of the monitor, a particular locator, and a particular tag, comprising a message that includes a first group of slots and a second group of slots, the sender comprising:

means for transmitting a start of message signal;

means for selecting a series of slots, such that selected slots of the series are separated in time by more than a minimum number of slots;

means for transmitting a signal in the first group of slots to convey an assertion in each of the slots of the series, and to convey the series in a progressive order; and

means for transmitting a signal in the second group of slots to convey an assertion in each of the slots not in the series, and to convey the series in regressive order.

31. A monitoring system comprising:

a plurality of locators, each locator for transmitting a respective locator message, the locator message comprising indicia of locator identity;

a plurality of tags, each tag for receiving at least one locator message and for transmitting a respective tag message, the tag message in accordance with a particular locator message, the tag message comprising indicia of tag identity, indicia of locator identity, indicia of time the particular locator message was received, and indicia of received signal strength of the particular locator message;

a monitor that determines, in accordance with received tag messages, a proximity between a particular tag and a particular locator corresponding to a particular time.

43. A monitoring system comprising:

a plurality of locators, each locator for transmitting a respective locator message, the locator message comprising indicia of locator identity;

a plurality of tags, each tag for receiving at least one locator message and for transmitting a respective tag message, wherein;

(1) the tag message is in accordance with a particular locator message, the tag message comprising indicia of tag identity, indicia of locator identity, and indicia of time the particular locator message was received;

(2) each tag transmits according to a respective beacon rate; and

(3) each tag transmits a respective tag message in accordance with a most recently received locator message;

a monitor that determines, in accordance with received tag messages, a proximity between a particular tag and a particular locator corresponding to a particular time.

44. A monitoring system comprising:

a plurality of locators, each locator for transmitting a respective locator message, the locator message comprising indicia of locator identity;

a plurality of tags, each tag for receiving at least one locator message and for transmitting a respective tag message, wherein;

(1) the tag message is in accordance with a particular locator message, the tag message comprising indicia of tag identity, indicia of locator identity, and indicia of time the particular locator message was received;

(2) at least one of a monitor and a locator of the plurality transmits a query; and

(3) the tag transmits a respective tag message in response to receiving the query; and

the monitor that determines, in accordance with received tag messages, a proximity between a particular tag and a particular locator corresponding to a particular time.

45. A monitoring system comprising:

a plurality of locators, each locator for transmitting a respective locator message, the locator message comprising indicia of locator identity;

a plurality of tags, each tag for receiving at least one locator message and for transmitting a respective tag message, wherein;

(1) the tag message is in accordance with a particular locator message, the tag message comprising indicia of tag identity, indicia of locator identity, and indicia of time the particular locator message was received;

(2) operation of the tag includes a plurality of modes comprising a first mode wherein transmitting is according to a beacon rate, each transmitted tag message in accordance with a respective most recently received locator message, and a second mode wherein transmitting is in response to receiving a query; and

(3) the tag selects a mode of operation from the plurality of modes in accordance with a command; and

a monitor that determines, in accordance with received tag messages, a proximity between a particular tag and a particular locator corresponding to a particular time, wherein at least one of a locator of the plurality and the monitor transmit the command.

46. The system of claim 45 wherein the particular tag determines a beacon rate in accordance with the command.

47. The system of claim 45 wherein:

the particular tag comprises a motion detector; and

the particular tag determines the beacon rate in response to the motion detector.

48. The system of claim 45 wherein the particular tag comprises:

a power supply circuit; and

a circuit selectively coupled to the power supply circuit in response to receiving the command.

49. A monitoring system comprising:

a locator for transmitting a respective locator message, the locator message comprising indicia of physical location of the locator;

a plurality of tags, each tag for receiving at least one locator message and for transmitting a respective tag message, the tag message in accordance with a particular locator message, the tag message comprising indicia of tag identity, and indicia of physical location of the locator, and indicia of time the particular locator message was received; and

a monitor that determines, in accordance with received tag messages, a proximity between a particular tag and the locator corresponding to a particular time.

50. The system of claim 49 wherein the locator comprises a global positioning system receiver that provides the indicia of physical location of the locator.

51. The system of claim 49 wherein the locator is mounted to a provided vehicle.

52. The system of claim 49 wherein the tag message further comprises indicia of received signal strength of the particular locator message.

53. The system of claim 49 wherein the locator, in operation, is being carried by a human operator.

54. A monitoring system comprising:

a plurality of means for transmitting a respective locator message, each locator message comprising location identification information;

a plurality of means for identifying an object, each means for identifying an object receiving at least one locator message and transmitting a respective tag message, the tag message in accordance with a particular locator message, the tag message comprising indicia of tag identity, location identification information, indicia of time the particular locator message was received, and indicia of received signal strength of the particular locator message;

a means for determining, in accordance with received tag messages, a proximity between a particular tag and a particular locator corresponding to a particular time.

55. The system of claim 54 wherein the means for determining includes a record for each means for transmitting, the record associating a respective physical location of a particular means for transmitting and a respective identity of the particular means for transmitting.

56. The system of claim 54 wherein a means for identifying of the plurality receives a plurality of locator messages in a time period, each locator message being associated with a respective received signal strength, and the means for identifying transmits, in response to the plurality of locator messages, a tag message in accordance with a particular locator message, of the plurality of locator messages, having the largest magnitude received signal strength.

57. The system of claim 54 wherein the means for identifying receives a plurality of locator messages in a time period, each locator message being associated with a respective received signal strength, and the means for identifying transmits a tag message corresponding to each received locator message.

58. The system of claim 54 wherein:

a particular means for identifying of the plurality transmits according to a beacon rate; and

the particular means for identifying transmits a tag message in accordance with a most recently received locator message.

59. The system of claim 54 wherein:

at least one of the means for determining and a means for transmitting of the plurality transmits a query; and

a means for identifying of the plurality transmits a tag message in response to receiving the query.

60. The system of claim 54 wherein:

operation of a particular means for identifying of the plurality includes a plurality of modes comprising a first mode wherein transmitting is according to a beacon rate, each transmitted tag message in accordance with a respective most recently received locator message, and a second mode wherein transmitting is in response to receiving a query; and

the particular means for identifying selects a mode of operation from the plurality of modes in accordance with a command.

61. The system of claim 60 wherein a means for transmitting of the plurality transmits the command.

62. The system of claim 60 wherein the means for determining transmits the command.

63. The system of claim 60 wherein the particular means for identifying determines a beacon rate in accordance with the command.

64. The system of claim 60 wherein:

the particular means for identifying comprises means for detecting motion; and

the particular means for identifying determines the beacon rate in response to the means for detecting motion.

65. The system of claim 60 wherein the particular means for identifying comprises:

a power supply circuit; and

a circuit selectively coupled to the power supply circuit in response to receiving the command.

66. A monitoring system comprising:

a plurality of means for transmitting a respective locator message, each locator message comprising respective location identification information;

a plurality of means for identifying objects, each means for identifying receiving at least one locator message and transmitting a respective tag message, wherein;

(1) the tag message is in accordance with a particular locator message, the tag message comprising indicia of tag identity, and location identification information, and indicia of time the particular locator message was received;

(2) each means for identifying transmits according to a respective beacon rate; and

(3) each means for identifying transmits a respective tag message in accordance with a most recently received locator message; and

means for determining, in accordance with received tag messages, a proximity between a particular tag and a particular locator corresponding to a particular time.

67. A monitoring system comprising:

a plurality of means for transmitting a respective locator message, each locator message comprising location identification information;

a plurality of means for identifying, each means for identifying receiving at least one locator message and transmitting a respective tag message, wherein;

(1) the tag message is in accordance with a particular locator message, the tag message comprising indicia of tag identity, location identification information, and indicia of time the particular locator message was received;

(2) at least one of a means for determining and a means for transmitting of the plurality transmits a query; and

(3) the means for identifying transmits a respective tag message in response to receiving the query; and

the means for determining that determines, in accordance with received tag messages, a proximity between a particular means for identifying and a particular means for transmitting corresponding to a particular time.

68. A monitoring system comprising:

a plurality of means for transmitting a respective locator message, each locator message comprising location identification information;

a plurality of means for identifying, each means for identifying receiving at least one locator message and transmitting a respective tag message, wherein;

(1) the tag message is in accordance with a particular locator message, the tag message comprising indicia of tag identity, location identification information, and indicia of time the particular locator message was received;

(2) operation of the means for identifying includes a plurality of modes comprising a first mode wherein transmitting is according to a beacon rate, each transmitted tag message in accordance with a respective most recently received locator message, and a second mode wherein transmitting is in response to receiving a query; and

(3) the means for identifying selects a mode of operation from the plurality of modes in accordance with a command; and

means for determining, in accordance with received tag messages, a proximity between a particular tag and a particular locator corresponding to a particular time, wherein at least one of a means for transmitting of the plurality and the means for determining transmit the command.

69. The system of claim 68 wherein the particular means for identifying determines a beacon rate in accordance with the command.

70. The system of claim 68 wherein:

the particular means for identifying comprises means for detecting motion; and

the particular means for identifying determines the beacon rate in response to the means for detecting motion.

71. The system of claim 68 wherein the particular means for identifying comprises:

a power supply circuit; and

a circuit selectively coupled to the power supply circuit in response to receiving the command.

72. A monitoring system comprising:

a means for transmitting a respective locator message, the locator message comprising indicia of physical location of the means for transmitting;

a plurality of means for identifying, each means for identifying receiving at least one locator message and transmitting a respective tag message, the tag message in accordance with a particular locator message, the tag message comprising indicia of tag identity, and indicia of physical location of the locator, and indicia of time the particular locator message was received; and

means for determining, in accordance with received tag messages, a proximity between a particular means for identifying and the means for transmitting corresponding to a particular time.

73. The system of claim 72 wherein the means for transmitting comprises a global positioning system receiver that provides the indicia of physical location of the means for transmitting.

74. The system of claim 72 wherein the means for transmitting is mounted to a provided vehicle.

75. The system of claim 72 wherein the tag message further comprises indicia of received signal strength of the particular locator message.

76. The system of claim 72 wherein the means for transmitting, in operation, is being carried by a human operator.

77. In a system for monitoring location of tags, the system comprising a monitor, a plurality of locators, and a plurality of tags, a method performed by the monitor comprising:

receiving a plurality of tag messages, each tag message comprising respective indicia of identity of a respective tag, and respective location identification information; and

determining a location of a particular tag corresponding to a particular indicia of identity in accordance with a multiplicity of tag messages.

78. The method of claim 77 wherein:

the method further comprises receiving a plurality of locator messages, each locator message comprising respective location identification information; and

determining is accomplished in further accordance with a multiplicity of locator messages.