| Summary: | 碩士 === 國立東華大學 === 資訊工程學系 === 98 === Radio Frequency Identification (RFID) is very popular technology at present, and many countries are all used at the world. Because of Wal-Mart had been proposed all products attach RFID tags and its security, high speed computing and high identification, RFID can be general used.
In the RFID identify procedure will cause collision. There are two major types on collision: the first is reader-collision and the second is tag-collision. A so-called tag-collision problem (or missed reads) in RFID system is the event that a reader cannot identify the tag if many tags respond to a reader at the same time. The tag-collision divides into aloha-based and tree-based protocols. Since aloha-based protocol will bring about starvation problem. Therefore it had proposed tree-based protocol to solve this problem. We discuss about tag-collision that is query tree anti-collision protocol. BQT protocol can succeed identification tags, when tags in the reader readable range. It will cause more collisions. Therefore it use M-ary Query Tree (MQT), the M is the number of split branch, for example, when M=2, 4, 8, and 16. The BQT protocol is M=2 MQT. MQT can reduce less collision but will cause more idle cycles. Hence we gain their benefits to avoid disadvantage.
In this thesis, we propose the Adaptive Query Tree (AQT) protocols that combine the multiple M-ary trees. The large M reduces collisions, while the small M avoids the unnecessary inquiries. Our AQT protocol successfully decreases the identification time by reducing the collisions and the idle time simultaneously. Two variant modes were proposed in our AQT, the base AQT (Base Adaptive Query Tree; BAQT) and the modified AQT (Modified Adaptive Query Tree; MAQT), designed for the random electronic product code (EPC) and the EPC with the first half bits are identical. Simulation results reveal that the proposed BAQT and MAQT outperform the BQT and MQT.
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