Identifying RFID categories

摘要

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.

主权项

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; andthe tag is adapted to transmit the uplink signal in the at least one selected slot in the multi-slot frame.