ABSTRACT
The Radio Frequency Identification (RFID) system is a non-contact automatic identification technology which is not only widely used in various modern industrial fields, but also in many new applications due to its advantages of small size and low cost. An important research area in RFID systems is how to quickly identify all tags which are located within the range of a reader. In order to achieve fast identification, we need to develop an effective anti-collision protocol between the reader and the tags. Many anti-collision protocols have been proposed in recent years. However, these anti-collision algorithms are almost aimed at the static environment, which means that the tags within a reader’s range will not be changed during the identification process. On the contrary, in the dynamic environment of RFID systems, some identified tags are removed and new tags move in regularly such as in inventory management application. The reader in such environment needs to re-identify the tags regularly. The previous proposed dynamic identification method cannot fully utilize the results from previous identification process which results the collisions and idles have occurred again in the new identification process. As a result the identification process is inefficient. In this paper, we propose an efficient protocol, called the Leaf Node Bit Collision Detection Based Query Tree (LBQT) algorithm. Our proposed LBQT algorithm can reduce the unnecessary queries for the unchanged tags and quickly identify the new coming tags. Experimental results show that the proposed algorithm outperforms previous protocols regardless the various density of tag distributions.
