RFID (Radio Frequency Identification) is one of the key automatic identification technologies in today’s ubiquitous computing system. It can be used for objects identification and assets tracing automatically and remotely by contact-less intercommunication and data changing. Along with the thorough application of the large-scale integrated circuit and the demand of the multiple objects identification, RFID is taken into a new seedtime. However, the collision problem which often happens in RFID system influences the system performance badly. So the approach to solve the collision problem must be taken to improve the identification efficiency. As RFID anti-collision algorithm has developed for many years, it has been in the stage of boom development and become to a hotspot in RFID system. In this paper, we propose several new tag anti-collision algorithms to overcome the disadvantages of the existing algorithms working in the range of high frequency and UHF, and simulation models are designed according to the algorithm characteristics. The simulation result shows that, the algorithms we proposed can improved the system throughput and shorten the identification time delay in some degree. The contents and main contributions of this thesis are as follows: 1. Analyze the state-of-the-art about the RFID tag anti-collision algorithms, and compare their performances and features. At present, most of the products are provided with the function of anti-collision, and all the standards have been defined the anti-collision scheme. Aim at different application setting, researchers have proposed many algorithms. In this paper, we analyze the state-of-the-art of the RFID anti-collision algorithms and compare their performances. 2. Research on the representative tag anti-collision algorithms working in the range of high frequency. RFID system working in the range of high frequency is well developed. Now there are several influential anti-collision algorithms in this range. In this paper, we analyze two type representative algorithms----dynamic frame slotted Aloha algorithm and the algorithm defined in the ISO 15693 protocol. Basic on the analysis, we propose two improved algorithms, overcoming the disadvantages in the original algorithms. 3. Research on the representative tag anti-collision algorithms working in the range of UHF---algorithm working in EPC Gen2 EPC Gen2 protocol is a UHF RFID standard developing in these years, whose well capability, secrecy and better adaptability makes it quickly become a hotspot since its emerging. In this paper, we research on its Q value adjusting method and the process of this important protocol, then we propose an improved algorithm, which improves its system throughput and reduce its identification delay.
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