Fast and reliable unknown tag detection in large-scale RFID systems

One of the most important applications of Radio Frequency Identification (RFID) technology is to detect unknown tags brought by new tagged items moved in, misplacement, or counterfeit tags. While unknown tag identification is able to pinpoint all the unknown tags, probabilistic unknown tag detection is preferred in large-scale RFID systems that need to be frequently checked up, e.g., real-time inventory monitoring. Nonetheless, we find that the efficiency of most previous works is not well optimized due to the transmission of unhelpful data. In this paper, we propose a fast and reliable method for probabilistic unknown tag detection, White Paper (WP) protocol. The key novelty of WP is to build a composite message data structure that consists of all the informative data from several independent detection synopses, i.e., excluding the useless data from communication. Hence, this design allows us to optimize the detection and communication efficiency at the same time. In particular, the compact detection synopsis is designed and tuned to minimize the failure probability for detection and the detection message is compositely constructed to reduce the transmission overhead, achieving the optimal detection and communication efficiency, respectively. We implement a prototype system using USRP software-defined radio and WISP tags to show the feasibility of this design. We also conduct extensive simulations and comparisons to show that WP achieves more than 2x performance gain compared to the state-of-the-art protocols.