Missing tag identification in open RFID systems

Abstract

Radio Frequency Identification (RFID) technology has been widely used in missing tag identification to reduce the economic loss caused by theft. Although many advanced works have been proposed, they cannot work properly in an open RFID system with unexpected tags. To solve the problem, this paper proposes an order-based missing tag identification protocol (OMTI) that efficiently identifies all missing tags even with the presence of unexpected tags. The key of OMTI is that we dynamically assign each tag a slot rather than use random hashes in traditional design. Namely, OMTI off-line sorts all known tags in advance by assigning each of them a unique and continuous slot, on-line identifies missing tags by checking tags' responses in each slot, and dynamically updates the slot assignment to ensure the high efficiency of the next execution. Besides, we enhance OMTI to make it works in the case of newly added tags. The simulation results demonstrate that OMTI can reduce the execution time by a factor of 12, compared with the polling-based approach.