Radio frequency identification architecture
View Patent ↗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.
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.