Method of addressing messages and communications system
First Claim
1. A system for performing radio frequency communications, the system comprising:
- a radio frequency identification (RFID) tag attached to one or more items to be tracked, the RFID tag generating a first random number and a second random number, the RFID tag configured to communicate a response including at least one of the first random number and the second random number at a time based at least in part on the second random number upon receipt of a request identifying a subgroup that includes the first random number;
one or more antennas positioned in a first region; and
an interrogator communicatively coupled to the one or more antennas to transmit one or more requests and to receive one or more responses, the interrogator being configured to repeatedly define a subgroup of possible random numbers such that each subgroup is a subset of a previous subgroup and to transmit requests for RFID tags having a random number within the subgroup until the interrogator receives the response from the RFID tag without a collision.
2 Assignments
0 Petitions
Accused Products
Abstract
A method of establishing wireless communications between an interrogator and individual ones of multiple wireless identification devices, the method comprising combining tree search and Aloha methods to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision. A system comprising an interrogator, and a plurality of wireless identification devices configured to communicate with the interrogator in a wireless fashion, the respective wireless identification devices having a unique identification number, the interrogator being configured to employ tree search and Aloha techniques to determine the unique identification numbers of the different wireless identification devices so as to be able to establish communications between the interrogator and individual ones of the multiple wireless identification devices without collision by multiple wireless identification devices attempting to respond to the interrogator at the same time.
119 Citations
40 Claims
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1. A system for performing radio frequency communications, the system comprising:
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a radio frequency identification (RFID) tag attached to one or more items to be tracked, the RFID tag generating a first random number and a second random number, the RFID tag configured to communicate a response including at least one of the first random number and the second random number at a time based at least in part on the second random number upon receipt of a request identifying a subgroup that includes the first random number; one or more antennas positioned in a first region; and an interrogator communicatively coupled to the one or more antennas to transmit one or more requests and to receive one or more responses, the interrogator being configured to repeatedly define a subgroup of possible random numbers such that each subgroup is a subset of a previous subgroup and to transmit requests for RFID tags having a random number within the subgroup until the interrogator receives the response from the RFID tag without a collision. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A radio frequency identification (RFID) tag comprising:
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a substrate; an antenna on the substrate; and an integrated circuit operably coupled to the antenna to receive a request, the request including an indication of a subset of possible random numbers, the integrated circuit configured to cause the antenna to communicate a response at a time based at least in part on a first random number generated by the RFID tag, the response including a second random number generated by the RFID tag. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. An interrogator comprising:
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one or more antennas; a receiver communicatively coupled to at least one of the one or more antennas to receive a response from a radio frequency identification (RFID) tag, the response including at least a first random number generated by the RFID tag; a transmitter communicatively coupled to at least one of the one or more antennas to transmit requests, one or more of the requests including an indication of a subgroup of possible random numbers; and a control unit communicatively coupled to the transmitter and the receiver, the control unit configured to repeatedly determine the subgroup for a first request such that the subgroup includes a smaller number of possible random numbers than a previous subgroup and cause the transmitter to transmit the first request until the control unit receives the response without a collision occurring between a plurality of responding RFID tags, wherein the receiver is configured to receive the response at a time based at least in part on a second random number generated by the RFID tag after the transmitter transmits the first request. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method for performing radio frequency communications, the method comprising:
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receiving a request, said request including a defined subgroup of possible numbers; generating a first random number and a second random number; and communicating a response including at least one of the first random number and the second random number at a time based at least in part on the second random number upon receipt of a request identifying the defined subgroup. - View Dependent Claims (25, 26, 27)
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28. A radio frequency device comprising:
an integrated circuit coupled to an antenna so as to receive a request, the request including an indication of a subset of possible numbers, the integrated circuit configured to cause the antenna to communicate a response at a time based at least in part on a first random number generated by the radio frequency device, the response including a second random number generated by the radio frequency device. - View Dependent Claims (29, 30)
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31. An interrogation apparatus, comprising:
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one or more antennas; a receiver communicatively coupled to at least one of the one or more antennas to receive a response from a radio frequency device, the response including at least a first random number generated by the radio frequency device; a transmitter communicatively coupled to at least one of the one or more antennas to transmit requests, one or more of the requests including an indication of a subgroup of possible numbers; and a control unit communicatively coupled to the transmitter and the receiver, the control unit configured to repeatedly determine the subgroup for a first request such that the subgroup includes a smaller number of possible numbers than a previous subgroup, and cause the transmitter to transmit the first request until the control unit receives the response without a collision occurring between a plurality of responding radio frequency devices; wherein the receiver is configured to receive the response at a time based at least in part on a second random number generated by the radio frequency device after the transmitter transmits the first request. - View Dependent Claims (32, 33, 34, 35)
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36. A method for performing radio frequency communications, the method comprising:
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a step for receiving a request including a defined subgroup of possible numbers; a step for generating a first random number and a second random number; and a step for communicating a response including at least one of the first random number and the second random number at a time based at least in part on the second random number upon receipt of a request identifying the defined subgroup. - View Dependent Claims (37, 38)
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39. An interrogation apparatus, comprising:
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an antenna; means for receiving a response from a radio frequency device via the antenna, the response including at least a first random number generated by the radio frequency device; means for transmitting requests via the antenna, one or more of the requests including an indication of a subgroup of possible numbers; and control logic communicatively coupled to the transmitter and the receiver, the control logic configured to repeatedly determine the subgroup for a first request such that the subgroup includes a smaller number of possible numbers than a previous subgroup, and cause the means for transmitting to transmit the first request until the control logic receives the response without a collision occurring between a plurality of responding radio frequency devices; wherein the means for receiving is configured to receive the response at a time based at least in part on a second random number generated by the radio frequency device after the means for transmitting transmits the first request. - View Dependent Claims (40)
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Specification