Studies On Anti-collision Algorithms Used In Uhf Rfid

RFID(Radio Frequency Identification)is a technology that has been developed since 1980s,it identities the target via radio, and it has many advantages, such as contactlessness, anti-jamming capability, can identify multiple targets and can rewrite data, etc. Now it is widely used in various industries.This paper describes the radio frequency identification's characteristics, research, physics, communications technology, standards,and so on, and it focuses on the key technologies of radio frequency identification application: anti-collision algorithm,and does simulation of the algorithms:Framed Slotted Aloha Algorithm, Dynamic Framed Slotted Aloha Algorithm, Algorithm based on Grouped Dynamic Framed Slotted Aloha and Binary Tree Search Algorithm.This paper has brought forward the Dynamic Framed Slotted Aloha Algorithm based on Transferring Random Number on basis of Dynamic Framed Slotted Aloha Algorithm. Algorithm requires that tag add a random number based on the original structure. It is generated by the random number generator or Algorithm which generates the slot random number, after a set of logical operations, a fixed format 8-bits number obtained. Once tag receives reader's requesting random command, it generates one of that random numbers and then sends to the reader. The fixed bits and format random number separate the tags which select the same slot. Position the tag together with the original slot random, so it can reduce the probability of tag collisions; thereby enhance the efficiency of recognition. After the program simulation by using Visual C++6.0 on the Dynamic Framed Slotted Aloha algorithm, the Algorithm based on Grouped Dynamic Framed Slotted Aloha and the Dynamic Framed Slotted Aloha Algorithm based on Transferring Random Number, and conduction of comparative analysis. The results show that the Dynamic Framed Slotted Aloha Algorithm based on Transferring Random Number's performance is better than the first two algorithms.Last chapter also describes the impact of ultra-high frequency RFID: tag's number estimation algorithm, random number generation algorithm and interference. And proposed UHF RFID systems should pay attention to several issues when is identifying tags: Analyze the environment before install or use the UHF RFID systems; Select the appropriate anti-collision algorithm; Human interference should be avoided; adjust the number of overlapping tags and the angle of the tags reasonable.