The Research On The Anti-collision Algorithm In RFID

Radio Frequency Identification(RFID)is a type of technology that use radio frequency to make non-contacting bidirectional database transmission between the readers and tags, in order to achieve the target identification and data exchange. Because of its advantages, such as non-contacted identification, able to identify high-speeding objects, avoid bad environment, has strong confidential and can identify more than one object; the RFID has become the fastest growing technology in the automatic identified data collecting field at present, and it is more and more extensively applied in the areas such as traffic control, warehousing management and automated production line management, etc.The tag anti-collision algorithm is the key technology of RFID, the realization of anti-collision also is the necessity whether RFID system can be used. This paper introduced the components of RFID system and its operating principle at the beginning, and then drew out the anti-collision problem. Furthermore, the solution to tags collision problem was studied, direct to the tags collision that happens in the process of tag identification. After analyzed the features of the current tag anti-collision algorithms, this paper put forward two improved deterministic tag anti-collision algorithms: the improved tree search algorithm based on dynamic binary system and the improved tree search algorithm based on subset division.The improved tree search algorithm based on dynamic binary system through simplify the order send by reader and the collision detection process, and use stack to save the tag's EPC data that had been received by the reader, which can greatly reduce the number of bits transferred between the reader and the tags, and get much better performance for identifying a large amount of tags. On the other hand, the improved tree search algorithm based on subset division continues the fine data transmission strategy of the dynamic binary system based improved tree search algorithm; and it is improved to reduce the chance of tag collision through divide tag subsets, which reduced the reader's inquiry frequency.The simulation results show that compared with the current binary-tree search algorithms, the two improved algorithms in this thesis have significantly enhanced the identification performance, particularly in the case of large number of non-identified tags exist, so they have a bright future in the application.