Radio frequency identification architecture

• US 7,212,125 B2
• Filed: 11/14/2005
• Issued: 05/01/2007
• Est. Priority Date: 02/12/2001
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Bandy, William R., Powell, Kevin J., Shanks, Wayne E., Arneson, Michael R.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US11/272,136
• Publication Number:
  US 20060082458A1
• Time in Patent Office: 533 Days
• Field of Search: 340/568.1, 340/568.6, 340/571, 340/572.1, 340/572.4, 340/10.3, 340/10.32, 340/825.49, 340/5.1, 235/487, 235/488, 700/213
• US Class Current: 340/572.7
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 19/0713 the arrangement including a power charge pump
• 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 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• 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 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• 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: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G08B 13/2485 Simultaneous detection of multiple EAS tags
• CPC Class Codes: G11C 5/142 Contactless power supplies, e.g. RF, induction, or IR
• CPC Class Codes: H04L 7/0331 with a digital phase-locked loop [PLL] processing binary samples, e.g. add/subtract logic for correction of receiver clock H04L7/0337 takes precedence

Abstract

A radio frequency identification (RFID) architecture is described. RFID tags are interrogated by a reader, which may be located in a network of readers. The reader transmits symbols to the tags. Tags respond to the interrogations with symbols that each represent one or more bits of data. An RFID tag includes an antenna pad, a receiver, a state machine, and a modulator. The receiver is coupled to the antenna pad. The receiver receives a symbol from the antenna pad and outputs a received signal. The state machine is configured to determine a response symbol from the received signal and an operating state of the tag. The modulator is coupled to the antenna pad. The modulator is configured to backscatter modulate the received symbol with the response symbol. The modulator is configured to output the backscatter modulated symbol to the antenna pad.

Claims

1. A reader network, comprising:

a sensor interface module (SIM) that includes a processor and configures data according to a communication protocol;

a remote access sensor module (RASM) coupled to the SIM through a first network, wherein the RASM includes a transmitter and a receiver; and

an antenna coupled to the RASM;

wherein the RASM receives the data from the SIM, wherein the transmitter modulates the data on a carrier signal, wherein the antenna transmits the modulated carrier signal.

2. The reader network of claim 1, wherein the carrier signal is backscatter modulated with tag data by a tag and is received by the antenna, wherein the receiver demodulates the backscatter modulated signal to recover the tag data.

3. The reader network of claim 2, wherein the SIM receives the tag data from the RASM and decodes the tag data.

4. The reader network of claim 1, further comprising:

a second antenna coupled to the RASM.

5. The reader network of claim 4, further comprising:

a multiplexer that couples the first and second antennas to the RASM, wherein the RASM controls the multiplexer to select one of the first and second antennas.

6. The reader network of claim 4, wherein the RASM further comprises a second transmitter coupled to the second antenna, and a second receiver coupled to the second antenna.

7. The reader network of claim 1, further comprising:

a plurality of antennas, each antenna of the plurality of antennas coupled to the RASM.

8. The reader network of claim 7, further comprising:

a plurality of multiplexers that couple the plurality of antennas to the RASM.

9. The reader network of claim 1, further comprising:

a second RASM coupled to the SIM through the first network, wherein the second RASM includes at least one transmitter and at least one receiver; and

at least one antenna coupled to the second RASM.

10. The reader network of claim 1, further comprising:

a plurality of RASMs, each RASM of the plurality of RASMs coupled to the SIM through the first network, wherein each RASM of the plurality of RASMs includes at least one transmitter and at least one receiver; and

a plurality of antennas that are coupled to the plurality of RASMs.

11. The reader network of claim 1, wherein said first network includes a connection point that couples the RASM to the first network.

12. The reader network of claim 1, further comprising:

a power supply coupled to the RASM.

13. The reader network of claim 1, further comprising:

a second RASM coupled to the SIM through a second network, wherein the second RASM includes at least one transmitter and at least one receiver; and

at least one antenna coupled to the second RASM.

14. The reader network of claim 1, further comprising:

a second SIM coupled to the first SIM through a communications link.

15. The reader network of claim 14, wherein the communications link is an Ethernet link.

16. The reader network of claim 14, wherein the communications link is a local area network (LAN).

17. The reader network of claim 14, further comprising:

at least one RASM coupled to the second SIM through a second network, wherein the at least one RASM includes at least one transmitter and at least one receiver; and

at least one antenna coupled to the at least one RASM.

18. The reader network of claim 14, wherein an application communicates with at least one of the first and second SIMs through the communications link.

19. The reader network of claim 14, wherein the communications link is coupled to a wide area network (WAN).

20. The reader network of claim 19, wherein an application communicates with at least one of the first and second SIMs through the WAN.

21. A system for tracking baggage in an airport, comprising:

at least one sensor interface module (SIM) that includes a processor and configures data according to a communication protocol;

a plurality of read points arranged in an airport space, each read point coupled to the at least one SIM, each read point including an antenna;

an application coupled to the SIM;

wherein a read point of the plurality of read points transmits a symbol and receives a response signal from a tag associated with a baggage;

wherein the SIM decodes the response signal into data, and transmits the data to the application;

wherein the application determines a location associated with the read point, and transmits the determined location to a cell phone of a person associated with the baggage, whereby the person determines a location of the baggage.