An Efficient Anti-Collision Protocol for the Sequential Distribution of Tag IDs in RFID Systems

Radio Frequency Identification (RFID) is a modern technology that uses radio frequencies to identify tags rapidly. However, since tags share the communication channel, a collision is occurred when more than one tag communicate with the reader simultaneously which results in a data transmission failure. Many tree-based protocols were proposed to resolve such conflictions in the past decade. Most of them were requiring a uniform distribution of tag IDs, which means that they were close related to the tag ID distribution. In fact, the tag IDs usually are not distributed uniformly especially in a large-scale RFID system. For example, in a large shopping mall, the tag IDs of all the merchandize can be classified into several groups depending on the number different vendors for providing all the merchandise. Since all the tag IDs of merchandise for the same vendor can contain the same prefix bits in their tag IDs, such distribution can be classified as the sequential tag ID distribution. The influence of sequential distribution of tag IDs on the protocol's behavior is studied in this paper. We propose a new scheme called Enhanced Flexible Query Window Tree (EFQwT) protocol to improve the performance of tag identification process. Our purpose is to design an effective anti-collision protocol to identify tag IDs that are distributed sequentially. The simulation results indicate that the proposed EFQwT protocol significantly reduces the time and energy consumption of identifying sequential tag IDs.