An RFID tag is provided including an object ID and a counter. Such an RFID tag may be employed in an RFID tag system including a parent RFID tag having an object ID and a counter, a child RFID tag, and a reader/writer configured to read the object ID and the counter of the parent RFID tag, combine values...http://www.google.fr/patents/US8040242?utm_source=gb-gplus-shareBrevet US8040242 - Hierarchical RFID
