Method and system for networking radio tags in a radio frequency identification system

• US 20060066444A1
• Filed: 11/09/2005
• Published: 03/30/2006
• Est. Priority Date: 07/20/1999
• Status: Active Grant

• Current Assignee: Axcess International, Inc. (Amphion Innovations PLC)
• Original Assignee: Axcess, Inc.
• Inventors: Steeves, Wayne E.
• Granted Patent: US 7,629,886 B2
• Time in Patent Office: Days
• US Class Current: 340/10.500
• 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: G08B 13/1427 with transmitter-receiver for distance detection
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00

Abstract

A radio frequency tag for a radio frequency identification system is provided that includes an antenna and a receiver coupled to the antenna. The receiver receives and demodulates a message received on at least one frequency. A retransmit controller receives the message, determines a retransmit status for the message, and if the retransmit status is positive, initiates retransmission of the message for reception by another radio tag.

Claims

1. A radio frequency tag for a radio frequency identification system, comprising:

an antenna system;

a receiver coupled to the antenna system to receive and demodulate a message on at least one frequency; and

a retransmit controller operable to receive the message, determine a retransmit status for the message, and initiate retransmission of the message for reception by another radio frequency tag in response to a positive retransmit status for the message.

2. The radio frequency tag of claim 1, further comprising a transmitter coupled to the antenna system and the retransmit controller to retransmit the message for reception by another radio frequency tag.

3. The radio frequency tag of claim 1, further comprising a computer-readable medium, the retransmit controller comprising a computer program encoded on the computer-readable medium, the computer program operable to determine the retransmit status for the message and initiate retransmission of the message in response to a positive retransmit status.

4. The radio frequency tag of claim 1, further comprising a local power supply.

5. The radio frequency tag of claim 1, the receiver further comprising:

a first receiver coupled to the antenna system to receive and demodulate messages from a first unit type at a first frequency; and

a second receiver coupled to the antenna system to receive and demodulate messages from a second unit type at a second disparate frequency.

6. The radio frequency tag of claim 5, wherein the second unit type has a limited local power supply and the first frequency is a lower frequency than the second disparate frequency.

7. The radio frequency tag of claim 6, wherein the first unit type is a radio frequency tag and the second unit type is another radio frequency tag.

8. The radio frequency tag of claim 6, wherein the first unit type is a base station and the second unit type is another radio frequency tag.

9. The radio frequency tag of claim 6, wherein the first frequency is a very low frequency.

10. The radio frequency tag of claim 6, wherein the second frequency is an ultra high frequency.

11. A radio frequency identification system, comprising:

a base station operable to communicate messages with radio frequency tags within the operational range of the base station;

a plurality of radio frequency tags each comprising;

an antenna system;

a receiver coupled to the antenna to receive and demodulate messages from the base station and the other radio frequency tags on at least one frequency; and

a retransmit controller operable to receive the messages, determine a retransmit status for each message, and initiate retransmission of the message within the operational range of the radio frequency tag in response to a positive retransmit status for the message.

12. The radio frequency identification system of claim 11, the plurality of radio frequency tags each further comprising a transmitter coupled to the antenna system and the retransmit controller to retransmit the message for reception by another radio frequency tag.

13. The radio frequency identification system of claim 11, the plurality of radio frequency tags each further comprising a computer-readable medium, the retransmit controller comprising a computer program encoded on the computer-readable medium, the computer program operable to determine the retransmit status for the message and initiate retransmission of the message in response to a positive retransmit status.

14. The radio frequency identification system of claim 11, the plurality of radio frequency tags each further comprising a local power supply.

15. The radio frequency identification system of claim 11, the receiver in each of the plurality of radio frequency tags further comprising:

a first receiver coupled to the antenna system to receive and demodulate messages from a first unit type at a first frequency; and

a second receiver coupled to the antenna system to receive and demodulate messages from a second unit type at a second disparate frequency.

16. The radio frequency identification system of claim 15, wherein the second unit type has a limited local power supply and the first frequency is a lower frequency than the second disparate frequency.

17. The radio frequency identification system of claim 16, wherein the first unit type is a base station and the second unit type is another radio frequency tag.

18. The radio frequency identification system of claim 16, wherein the first frequency is a very low frequency.

19. The radio frequency identification system of claim 16, wherein the second frequency is an ultra high frequency.

20. A method for communication between a base station and a plurality of radio frequency tags in a radio frequency identification system, comprising:

transmitting a query message from the base station;

each of the radio frequency tags receiving the query message, determining a retransmit status for the query message, and retransmitting the query message in response to a positive retransmit status;

each radio frequency tag receiving the query message, determining a response status for the query message, and transmitting a response message for the base station in response to a positive response status; and

each radio frequency tag receiving a response message from another radio tag, determining a retransmit status for the response message, and retransmitting the response message in response to a positive retransmit status.

21. The method of claim 20, further comprising:

the base station transmitting the query message at a first frequency; and

the radio frequency tags each transmitting and retransmitting query and response messages at a second disparate frequency.

22. The method of claim 20, wherein the first frequency is a very low frequency (ULF).

23. The method of claim 20, wherein the second frequency is an ultra high frequency (UHF).

24. A method for processing a message in a network radio frequency tag, comprising:

receiving a message;

determining a response status for the message;

transmitting a response to the message in response to a positive response status;

determining a retransmit status for the message; and

retransmitting the message in response to a positive retransmit status.

25. The method of claim 24, the message including a destination address, the step of determining a retransmit status for the message comprising:

comparing the destination address of the message to an address of the network radio frequency tag; and

determining a positive retransmit status in response to the network radio frequency tag address not matching the destination device address.

26. The method of claim 24, the message including a destination address, the step of determining a retransmit status comprising:

comparing the destination address of the message to an address of the network radio frequency tag;

determining whether the message has been previously retransmitted by the network radio frequency tag; and

determining a positive retransmit status in response to the network radio frequency tag address not matching the destination address of the message and the message not being previously retransmitted by the network radio frequency tag.

27. The method of claim 24, determining a retransmit status for the message comprising:

identifying the message as a global message; and

determining a positive retransmit status in response to the message being identified as a global message.

28. The method of claim 24, determining a retransmit status for the message comprising:

identifying the message as a global message;

determining whether the message has been previously retransmitted by the network radio frequency tag; and

determining a positive retransmit status in response to the network radio frequency tag address not matching the destination address of the message and the message not being previously retransmitted by the network radio frequency tag.

29. The method of claim 24, further comprising:

generating an acknowledge message in response to completely receiving the message; and

transmitting the acknowledge message.

30. The method of claim 24, further comprising:

generating an unacknowledge message in response to partially receiving the message; and

transmitting the unacknowledge message.

31. The method of claim 24, further comprising:

receiving an unacknowledge message to a previously retransmitted message; and

retransmitting the message in response to the unacknowledge message.