Hash Based Collision Resolution for Passive RFID Tags

Abstract

RFID technology has recently attracted renewed interest due to the major promotion from global retailers. In this paper, we consider the tag collision problem that prevents the reader from identifying the adjacent tags in certain applications. We propose a hash based algorithm that requires neither memory nor battery in the tag. Only simple arithmetic capability is necessary. The proposed algorithm guarantees complete tag reading while reserving the power in the reader. Using the information collected by the reader, it increases the speed of repeated readings of the tags moving in and out of the reading zone. We compare our algorithm with two algorithms based on query-tree searching and on dynamic reading frames. We show that the proposed algorithm is the most effective in terms of the detection speed and number of reader messages. Keywords: RFID, collision resolution, query-tree, hash algorithms