The Research On Anti-collision Algorithm In RFID

Radio Frequency Identification (RFID) is a contactless, low power , and low cost wireless communication technology. RFID enables identification from a distance. RFID offers great benefits for supply chain management, inventory control, and many other applications. Owing to the shared wireless channel between tags and reader during communication, collisions will occur, when lots of tags reply to reader in the same time. In this moment, reader cannot identify the response which was generated by which tags. How to reduce the collision rate is the key point that can influence the performance of an RFID system. Therefore, a good anti-collision algorithm plays an important role for an efficient RFID system.The existing anti-collision methods are unable to provide better reading results. So, the researches in this thesis focus on the anti-collision methods in RFID.This paper firstly introduces the principle of RFID system, expounds the development and significance of anti-collision technology in RFID. Then some common anti-collision algorithms are simulated and compared.An improved anti-collision algorithm based on B+ tree was proposed. In the algorithm, the Collision tags aggregation splits into three smaller aggregations at each round so as to quicken the rate of splitting. Collision aggregation corresponds to the intermediate node of the B+ tree. Each key corresponds to a splitted aggregation. Each leaf of the tree contains one tag or null. Meanwhile this algorithm made use of hash operation to average splitting. Simulating results show that the B+ algorithm reduced collision, shortened the identify delay and improved the identify performance.A secure anti-collision algorithm based on B+ tree was proposed. It adds security to the anti-collision algorithm. It advances a new idea that making security test before the anti-collision process. It can make double protecting in the situation of multi-tags.An improved B+ tree anti-collision algorithm was proposed. It improves the B+ algorithm, and inherits the advantages of which. It uses Manchester code and array to reduce the time of identifying. The simulation shows that the proposed scheme uses fewer time for indentifying tags.