Radio frequency identification system with write broadcast capability

• US 5,942,987 A
• Filed: 08/09/1996
• Issued: 08/24/1999
• Est. Priority Date: 09/09/1994
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: McAuliffe, Kevin G, Goldman, Kenneth Alan, Friedman, Daniel J., Heinrich, Harley Kent, Cofino, Thomas A., Cesar, Christian Lenz, Greene, Sharon Louise
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): WILSON JR, WILLIAM HALL
• Application Number:
  US08/694,606
• Time in Patent Office: 1,110 Days
• Field of Search: 340/825.54, 340/825.69, 340/825.71, 340/825.72, 340/505, 340/568, 340/572, 340/572.1, 340/572.3, 340/572.4, 342/44, 342/51, 367/2, 367/6, 455/140, 365/192
• US Class Current: 340/10.42
• 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 7/10039 interrogator driven, i.e. synchronous
• CPC Class Codes: G06K 7/10108 interrogating only those RFIDs that fulfill a predetermined requirement, e.g. selecting all RFIDs having the same speed and moving in a cloud like fashion, e.g. on the same train; interrogating only RFIDs having a certain predetermined temperature, e.g. in the same fridge, another possibility being the active ignoring of a group of tags that fulfill a predetermined requirement, equivalent to the Boolean NOT operation
• CPC Class Codes: G07C 3/00 Registering or indicating the condition or the working of machines or other apparatus, other than vehicles
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: G08C 2201/20 Binding and programming of remote control devices

Abstract

A Write Broadcast system and method uses a base station to write sent data associated with no particular destination tag or tags, by radio frequency signal, to all or some selected number (sub group) of tags in a base station field simultaneously. By unselecting the tags that have been successfully written to, and requesting a response from the remaining tags in the field (or sub group), the system determines, by receiving a response to the request, that there are tags in the field (sub group) that were unsuccessfully written to. Another Write Broadcast signal is sent to these tags. The system is useful for quickly (simultaneously) "stamping" information on the tag memory of a large number of tags in the field of the base station.

Claims

1. A radio frequency transponder, comprising:

a transponder memory having a transponder data location with a data value stored in the transponder data location; and

a transponder receiver for receiving a broadcasted write signal not associated with said transponder, the signal having sent data and a sent address identifying the transponder data location and the receiver automatically writing the sent data to the transponder data location identified by the sent address in response thereto without first having sent a unique tag identifier to the base station, the transponder sending a response if the sent data is different than the stored data value, indicating that the transponder data location has been updated by the sent data, and the transponder not sending a response if the sent data is the same as the stored data value.

2. A radio frequency tag, comprising:

a tag antenna for receiving a radio frequency write signal broadcasted from a base station, the radio frequency signal containing sent data and and a sent address and not being associated in advance with said tag;

a tag memory having a tag data location identified by the sent address and containing old data;

a tag logic having an active state and an initialize state, a Select Command placing the tag in the active state if the tag meets a select condition and an Unselect Command placing the tag in the initialize state if the tag meets an unselect condition; and

a tag receiver for receiving the radio frequency write signal from the tag antenna, the tag automatically writing the sent data to the tag data location identified by the sent address if the tag is in the active state and the tag not writing the sent data to the tag data location identified by the sent address if the tag is in the initialize state.

3. A tag, as in claim 2, where the tag writes the sent data to the tag data location identified by the sent address without the tag sending a response containing a tag identifier.

4. A tag, as in claim 2, where the tag further comprises a decoder for decoding an Any Tag command that causes the tag to communicate a response when the tag is in the active state and that causes the tag not to communicate a response when the tag is in the initialize state.

5. A radio frequency tag, comprising:

a tag antenna for receiving a broadcasted radio frequency write signal from a base station, the radio frequency write signal identifying no particular destination tag and containing one or more sent data and one or more sent addresses corresponding to the sent data;

a tag receiver for decoding each of the sent data and the sent addresses from the radio frequency write signal;

a tag memory having one or more tag data locations, each tag data location having a respective tag data address;

a tag receiver for receiving the radio frequency signal from the tag antenna; and

a tag logic having an active state and an initialize state, a Select Command placing the tag in the active state if the tag meets a select condition and an Unselect Command placing the tag in the initialize state if the tag meets an unselect condition, the tag automatically writing each of the sent data into the tag data location with the tag data address identified by the respective sent address if the tag is in the active state and the tag not writing any of the sent data if the tag is in the initialize state, without the tag first sending a tag identifier to the base station.

6. A base station for communicating with radio frequency tags in a field of the base station, each of the tags having a tag memory, the base station comprising:

a signal generator that develops a signal containing sent data and a sent address and identifying no particular destination tag;

a base station transmitter that encodes the signal on the carrier to create an encoded signal; and

a base station antenna that transmits the encoded signal to two or more tags in the field causing the tags to simultaneously write the sent data into their tag memories at a tag data location identified by the sent address without the tags first sending tag identifiers to the base station,

the base station listening for a response from one or more tags, a response from one or more tags causing the base station transmitter to retransmit the encoded signal.

7. A base station, as in claim 6, where the sent data includes one of the following types of information:

object identification, object description, object use, object tracking, object location, object status, and object handling.

8. A base station for communicating with radio frequency tags in a field of the base station, each of the tags having a tag memory, the tag memory having a tag data location identified by a tag data address, the base station comprising:

a computer that develops a select command and a write broadcast signal, the write broadcast signal being associated with no particular destination tag or tags and containing a write broadcast command, sent data and a sent address;

a base station transmitter that encodes the select command on a radio frequency carrier to create a select signal and encodes the write broadcast signal on the radio frequency carrier to create a write signal; and

a base station antenna that transmits the select signal to all the tags in the field to select a subgroup of the tags, and subsequently transmits the write signal to simultaneously write the sent data to the tag data location having a tag data address corresponding to the sent address in the selected subgroup of the tags.

9. A radio frequency tagging system, as in claim 8 where the tags not in the selected subgroup do not respond to the write broadcast signal.

10. A radio frequency tagging system, comprising:

radio frequency tags, each tag having a tag logic, a tag antenna, and a tag data location; and

a base station having a signal generator, a transmitter, and a base antenna, the signal generator sending a carrier signal through the transmitter and base antenna into a field, the transmitter encoding sent data and a sent address generated by the signal generator onto the carrier signal to produce an encoded carrier signal associated in advance with no particular destination tag or tags, tags in the field receiving the carrier signal through their respective tag antennas and the tag logic of each tag in the field decoding the sent data and causing the sent data to be simultaneously written to the respective tag data location identified by the sent address, the tag logic causing the tag to send a response if the sent data is different than an old data in the tag data location and not send the response if the sent data is the same as the old data, the base station resending the encoded carrier signal if a response is received from one or more of the tags.

11. A radio frequency tagging system, comprising:

radio frequency tags, each tag having a tag logic and a tag antenna and each tag further having one or more tag data locations associated with a tag data address;

a base station having a computer, a transmitter, and a base antenna; and

a process executed by the computer that causes a radio frequency write broadcast signal associated with no particular destination tag(s) to be sent through the transmitter and base antenna into a field, the write broadcast signal having two or more sent data and a sent address corresponding to each of the sent data, tags in the field receiving the write broadcast signal through the tag antenna thereof and the tag logic of the tags in the field causing the sent data to be simultaneously written to the tag data locations of the tags that have a tag data address matching the respective sent address.

12. A system, as in claim 11, where the tag logic causes the tag to send a response if the sent data is different than an old data in the tag data location and not send the response if the sent data is the same as the old data, the base station resending the write broadcast signal if a response is received from one or more of the tags.

13. A radio frequency tagging system, as in claim 11, where the tags do not all respond to the write broadcast signal.

14. A radio frequency tagging system, as in claim 11, where the base station sends a group unselect command and one or more of the tags that has old data in the tag data location that does not match the sent data sends a response to the group unselect command to the base station.

15. A system, as in claim 11, where the sent data includes any one of the following types of information:

object identification, object description, object use, object tracking, object location, object status, and object handling.

16. A method performed by a base station comprising the steps of:

a. selecting a sub group of radio frequency tags in a field of tags by sending a select command, only the tags in the sub group being enabled to write sent data to respective tag memories of the tag;

b. sending a radio frequency signal identifying no particular destination tag or tags, the signal having sent data and causing enabled tags in the field to simultaneously write the sent data to a tag memory in the tags in the subgroup.

17. A method performed by a base station comprising the steps of:

broadcasting a radio frequency write signal associated with no particular destination tag(s) into a field of radio frequency tags, the write signal having one or more pairs of sent data and sent addresses, each sent address being associated with a sent data, and the write signal causing tags in the field to write each of the sent data to a tag data location in a tag memory, the tag data location having a tag data address equal to the sent address associated with the respective sent data; and

issuing an Unselect command that causes any tag in the field to respond if a value in a tag data location of such tag with a tag data address corresponding to a sent address does not equal the respective sent data.

18. A method, as in claim 17, where the base station re-sends the radio frequency signal if a response is received.

19. A method, as in claim 17, where there is no sent address in one or more of the pairs and the respective tag data locations are pre-assigned.

20. A method, as in claim 17, where there is one sent address that is paired with more than one of the sent data.

21. A radio frequency tag comprising:

a tag antenna means for receiving a radio frequency write broadcast signal from a base station, the radio frequency write broadcast signal containing sent data and a sent address and being associated with no particular destination tag(s);

a tag memory means having a tag data location identified by the sent address and containing old data;

a tag receiver means for receiving the radio frequency write broadcast signal from the tag antenna and writing the sent data to the tag data location identified by the sent address without first sending a unique tag identifier to the base station; and

a tag transmitter means for sending a response to the base station when the sent data is different than the old data in the tag data location identified by the sent address.

22. A base station for communicating simultaneously with a plurality of radio frequency tags in a field of the base station, each of the tags having a tag memory, the base station comprising:

a signal generator means for developing a signal containing sent data and a sent address;

a base station receiver;

a base station transmitter means for encoding the signal with the sent data and the sent address on a radio frequency carrier to create an encoded carrier; and

a base station antenna means for transmitting the encoded carrier simultaneously to the plurality of tags in the field,

the plurality of tags simultaneously writing the sent data into their tag memories at a tag data location identified by the sent address without first sending a unique tag identifier to the base station.

23. A radio frequency tag, comprising:

a tag antenna for receiving a broadcasted radio frequency write signal from a base station, the radio frequency write signal having sent data and a sent address and identifying no particular destination tag(s), and the tag antenna further for communicating one or more responses to the base station;

a tag memory having a tag data location identified by the sent address and containing old data;

a tag logic having an active state and an initialize state, a Select Command placing the tag in the active state if the tag meets a select condition and an Unselect Command placing the tag in the initialize state if the tag meets an unselect condition, where the tag in the active state that receives an Unselect Command and does not meet the unselect condition communicates one of the responses through the tag antenna to the base station;

a tag receiver for receiving the radio frequency write signal from the tag antenna, the tag writing the sent data to the tag data location identified by the sent address if the tag is in the active state and the tag not writing the sent data to the tag data location identified by the sent address if the tag is in the initialize state.

24. A tag, as in claim 23, where writing the sent data occurs in the tag without the tag sending a response containing a tag identifier.

25. A tag, as in claim 23, where writing the sent data causes the tag to send a response.

26. A tag, as in claim 23, where writing the sent data causes the tag to send a response if the sent data is different from the old data in the tag memory.

27. A base station for communicating simultaneously with a plurality of radio frequency tags in a field of the base station, each of the tags having a tag memory, the base station comprising:

a signal generator that develops a signal containing sent data and a sent address;

a base station transmitter that encodes the signal onto a carrier to create an encoded signal; and

a base station antenna that

transmits the encoded signal to the plurality of tags in the field for causing the tags to simultaneously write the sent data into their tag memories at a tag data location identified by the sent address without each of the tags first sending a unique tag identifier to the base station,

sends a group unselect command to the tags that unselects tags that have the sent data in their respective tag memories, and

listens for a response from one or more tags.

28. A base station, as in claim 27, where the response causes the base station transmitter to retransmit the encoded signal.

29. A base station, as in claim 27, where the response causes the base station to generate an error code.

30. A base station for communicating with a plurality of radio frequency tags in a field of the base station, each of the tags having a tag memory, the tag memory having one or more tag data locations and each of the tag data locations having a tag data address, the base station comprising:

a computer that develops an unselect command and a write broadcast signal, the write broadcast signal being associated with no particular destination tag(s) and containing a write broadcast command, sent data and a sent address;

a base station transmitter that encodes the unselect command on a radio frequency carrier to create an unselect signal and encodes the write broadcast signal on the radio frequency carrier to create a write signal; and

a base station antenna that transmits the unselect signal to all the tags in the field to unselect a subgroup of the tags, and subsequently transmits the write signal to all tags in the field to simultaneously write the sent data into the tags not in the unselected subgroup to the tag data location having the tag data address corresponding to the sent address.

31. A method performed by a base station, comprising the steps of:

a. selecting radio frequency tags in a field of tags by issuing one or more select and zero or more unselect commands, the selected tags becoming active and the not selected tags remaining initialized;

b. issuing an unselect command that causes unselected tags to become initialized if the value in each of the tag data locations with tag data addresses corresponding to a sent address are equal to sent data, and to remain active and respond if the value in any of tag data locations does not equal the sent data; and

c. issuing a write broadcast command associated with no particular destination tag or tags if any response is received to step b.

32. A method, as in claim 31, comprising the further step of:

d. repeating steps b and c until no tags respond.

33. A method, as in claim 31, comprising the further step of:

d. repeating steps b and c until an allowed number of iterations is reached.

34. A method performed by a base station comprising the steps of:

a. selecting zero or more of the radio frequency tags in a field of tags by issuing one or more select and zero or more unselect commands, the selected tags becoming active and the not selected tags remaining initialized;

b. issuing an unselect command that causes unselected tags to become initialized if the value in each of the tag data locations with tag data addresses corresponding to a sent address are equal to sent data, and to remain active and respond if the value in any of tag data locations does not equal the sent data; and

c. issuing a write broadcast command associated with no particular destination tag or tags if any response is received to step b.

35. A method, as in claim 34, further comprising the step of:

d. repeating steps a, b and c until no tags respond.

36. A method, as in claim 34, further comprising the step of:

d. repeating steps a, b and c until an allowed number of iterations is reached.