Study On Anti-collision Algorithm Of Multi-slotted With Assigned Slots Based On ALOHA

Radio Frequency Identification (RFID) is a contactless automatic identification technology rose from the 1990s, which applies and develops the automatic identification technology into radio technology. There are many advantages of RFID technology such as high accuracy ,strong ability to adapt to the environment, efficient operation, long service life, long reading distance, encrypted tag data, large data storage capacity, and so on. Along with the developing of RFID technology, RFID has more and more important effect on many areas such as supply chain management, logistics, automation, transportation management and control, retail, et al. RFID will become the mainstream of automatic identification technology and has broad prospects.Data integrity problem of RFID is one of the important factors that hinder thedevelopment of RFID. It is directly related to the quality of the performance of thewhole system level. Collision problem is an important aspect that affects the integrityof the data. There are two kinds of collision. They are reader collision and tagcollision. The way to solve the collision called the anti-collision algorithm.Comparing with the reader collision, the tag collision take place in a higher probability and the problem of tag anti-collision is considered to be an important issue to resolve. When more than one tag in the reader area and send datum to the reader at the same time, the signal of the tags will interferes each other and the tags will not be able to be identified. We call it tag collision. It belongs to the mufti-target identification problems. Because RFID is the only one technology that can identify mufti object at the same time, mufti-target identification is both the advantages and the challenge of RFID technology.In this thesis, we first brievly introduce some basic concepts about RFID, the problem of tag collision in RFID system, and present some currently popular anti-collision algorithms. On the basis of analyzing ALOHA scheme, some improving ALOHA schemes, Binary search scheme and some improving dynamic Binary search schemes, we proprose a new tag anti-collision algorithm—the multi-slotted with assigned slots based on ALOHA(AMAS)scheme. Because of the new scheme is not needed to send given information repeatly any more, the transmission number of redundant information was obtained the maxium reduction. Forthermore, the transfer code efficient is increased by double as the system does not adopt coding.The simulation results and mathematical analysis show that the performance of the new scheme proposed in this thesis is obviously better than the classical determistic algorithms. So, the new scheme can not only avoid tag collision efficiently, but also can cut down the reader power consumption. It is especially suitable for the multi-tags application enviroment.