Identifying RFID categories
First Claim
1. A tag for an RFID system, the tag comprising:
- a memory adapted to store a tag identification (ID) value for the tag, the tag ID value comprising (i) a category ID value shared with at least one other tag and selected from one of a plurality of predetermined values corresponding to different categories of RFID tags and (ii) an instance value;
an antenna adapted to receive a downlink signal from a reader and transmit an uplink signal to the reader; and
a processor adapted to process the downlink signal and generate the uplink signal, wherein;
the processor is adapted to select at least one slot in a multi-slot frame based on the stored category ID value, but independent of the stored instance value; and
the tag is adapted to transmit the uplink signal in the at least one selected slot in the multi-slot frame.
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Accused Products
Abstract
The set T of all categories in a population of RFID tags is estimated within a specified error bound. For each of one or more frames, a reader broadcasts a probability p, a multiplicity d, a frame size M, and a seed value R to the present tags. A deterministic algorithm on each tag, and known to the reader, calculates (i) whether the tag will transmit in this frame, and, if so, (ii) in which slots the tag will transmit a single “1.” When the tags have responded, the reader calculates set T by initially assuming that all possible categories are in set T and then eliminating those categories that would have transmitted in those slots in which no tag transmitted. Alternatively, the reader initially assumes that set T is empty, and adds those categories that would have transmitted in those slots in which one or more tags did transmit.
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Citations
15 Claims
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1. A tag for an RFID system, the tag comprising:
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a memory adapted to store a tag identification (ID) value for the tag, the tag ID value comprising (i) a category ID value shared with at least one other tag and selected from one of a plurality of predetermined values corresponding to different categories of RFID tags and (ii) an instance value; an antenna adapted to receive a downlink signal from a reader and transmit an uplink signal to the reader; and a processor adapted to process the downlink signal and generate the uplink signal, wherein; the processor is adapted to select at least one slot in a multi-slot frame based on the stored category ID value, but independent of the stored instance value; and the tag is adapted to transmit the uplink signal in the at least one selected slot in the multi-slot frame. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A tag for an RFID system, the tag comprising:
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a memory adapted to store a tag identification (ID) value for the tag, the tag ID value comprising (i) a category ID value shared with at least one other tag and selected from one of a plurality of predetermined values corresponding to different categories of RFID tags and (ii) an instance value; an antenna adapted to receive a downlink signal from a reader and transmit an uplink signal to the reader; and a processor adapted to process the downlink signal and generate the uplink signal, wherein; the processor is adapted to select at least one slot in a multi-slot frame; and the tag is adapted to transmit the uplink signal in each of the at least one selected slots in the multi-slot frame, wherein; the downlink signal comprises a multiplicity value indicating a number of slots; and the processor is adapted to select the at least one slot based on the multiplicity value. - View Dependent Claims (8, 9)
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10. A tag for an RFID system, the tag comprising:
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a memory adapted to store a tag identification (ID) value for the tag, the tag ID value comprising (i) a category ID value shared with at least one other tag and selected from one of a plurality of predetermined values corresponding to different categories of RFID tags and (ii) an instance value; an antenna adapted to receive a downlink signal from a reader and transmit an uplink signal to the reader; and a processor adapted to process the downlink signal and generate the uplink signal, wherein the uplink signal corresponds to a single bit value, wherein; the downlink signal comprises a probability value; and the processor is adapted to determine whether or not to transmit the uplink signal in a multi-slot frame based on the probability value.
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11. A reader for an RFID system, the reader comprising:
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a processor adapted to generate a downlink signal; an antenna adapted to transmit the downlink signal to one or more tags and receive one or more uplink signals from the one or more tags, wherein; one or more uplink signals comprises a tag ID value comprising (i) a category ID value shared by at least two tags and selected from one of a plurality of predetermined values corresponding to different categories of RFID tags and (ii) an instance value; and the processor is further adapted to process the one or more uplink signals to estimate the one or more categories without identifying any of the one or more tags. - View Dependent Claims (12, 13, 14, 15)
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Specification