Wireless identification systems and protocols

• US 7,030,731 B2
• Filed: 06/14/2002
• Issued: 04/18/2006
• 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
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): YANG, CLARA I
• Application Number:
  US10/172,713
• Publication Number:
  US 20030030568A1
• Time in Patent Office: 1,404 Days
• Field of Search: 340/10.1, 340/539.13, 340/573.1, 340/573.3, 340/573.4, 342/118, 342/126, 342/127, 342/128, 714/52, 714/799, 714/823, 341/173, 341/178, 341/179
• US Class Current: 340/10.1
• 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 7/10079 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, 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:

generating a first part of a message by inserting a high or low signal in each slot within a first group of slots, such that the high signals are separated in time by a minimum number of slots;

transmitting the first part of the message; and

transmitting a second part of the message, wherein the second part'"'"'s high and low signals within a second group of slots are in reverse order from those in the first part.

4. The method of claim 1, 2, or 3 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.

5. The method of claim 1, 2, or 3 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.

6. The method of claim 1, 2, or 3 wherein the message comprises indicia for identifying within the first group of slots a plurality of subparts.

7. The method of claim 1, 2, or 3 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.

8. The method of claim 1, 2, or 3 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.

9. The method of claim 1, 2, or 3 wherein the message comprises location identification information and a command.

10. The method of claim 1, 2, or 3 performed by at least one of the locator and the monitor, wherein the message comprises a command to be performed by the tag.

11. The method of claim 1, 2, or 3 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.

12. The method of claim 1, 2, or 3 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.

13. The method of claim 1, 2, or 3 wherein assertion comprises a code comprising a plurality of bits.

2. 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:

generating a first part of a message by inserting a high or low signal in each slot within a first group of slots, such that the high signals are separated in time by a minimum number of slots;

transmitting the first part of the message; and

transmitting a second part of the message, wherein the second part'"'"'s high and low signals within a second group of slots are inverse in magnitude from those in the first part.

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:

generating a first part of a message by inserting high or low signal in each slot within a first group of slots, such that the high signals are separated in time by a minimum number of slots;

transmitting the first part of the message; and

transmitting a second part of the message, wherein the second part'"'"'s high and low signals within a second group of slots are inverse in time and magnitude from those in the first part.

14. 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 generating a first part of a message by inserting a high or low signal in each slot within a first group of slots, such that the high signals are separated in time by a minimum number of slots;

means for transmitting the first part of the message; and

means for transmitting a second part of the message, wherein the second part'"'"'s high and low signals within a second group of slots are in reverse order from those in the first part.

17. The system of claim 14, 15, or 16 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.

18. The system of claim 14, 15, or 16 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.

19. The system of claim 14, 15, or 16 wherein the message comprises indicia for identifying within the first group of slots a plurality of subparts.

20. The system of claim 14, 15, or 16 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.

21. The system of claim 14, 15, or 16 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.

22. The system of claim 14, 15, or 16 wherein the message comprises location identification information and a command.

23. The system of claim 14, 15, or 16 wherein the message comprises a command to be performed by the tag.

24. The system of claim 14, 15, or 16 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.

25. The system of claim 14, 15, or 16 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.

26. The system of claim 14, 15, or 16 wherein assertion comprises a code comprising a plurality of bits.

15. 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 generating a first part of a message by inserting a high or low signal in each slot within a first group of slots, such that the high signals are separated in time by a minimum number of slots;

means for transmitting the first part of the message; and

means for transmitting a second part of the message, wherein the second part'"'"'s high and low signals within a second group of slots are inverse in magnitude from those in the first part.

16. 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 generating a first part of a message by inserting high or low signal in each slot within a first group of slots, such that the high signals are separated in time by a minimum number of slots;

means for transmitting the first part of the message; and

means for transmitting a second part of the message, wherein the second part'"'"'s high and low signals within a second group of slots are inverse in time and magnitude from those in the first part.