Research On RFID Tags Anti-collision Algorithm In Internet Of Things Communication

Radio Frequency Identification technology is a kind of noncontact automatic identification technology, which uses radio frequency signal to transmit data by space electromagnetic coupling. A reader and tags share the same transmission channel in RFID systems, when multiple tags simultaneously respond to the reader is bound to generate a signal interference, called collision. Compared for other algorithms, the recognition rate of tree-based algorithm reaches 100%, with higher throughput. The research direction of this paper is tree-based anti-collision algorithm.In this paper, research status of RFID technology, composition principle, workflow and other relative theory are introduced. And a detailed analysis and comparison of existing anti-collision algorithms is performed. Some innovation and improvement has been done on the existing anti-collision algorithms. The main innovations points are listed as follows:(1) An improved adaptive division collision tree algorithm (IACT) was proposed. The algorithm determines binary tree or quadtree by calculating collision factor. When using binary tree, if the collision bit is only one, tags can be identified directly without having to send commands. When using quadtree, reader first sends a command for tags to return the corresponding coding of the highest two collision bits, and obtains collision prefix by receiving information. Tags add storage mechanism to store prefix of the highest collision bits and status flag bit flag, when flag is 0 responding to reader. Flag is set to 1 no longer responds the reader. The performance of the algorithm and simulation results IACT algorithm can effectively reduce the total time slot and the communication load.(2) An enhanced quadtree anti-collision algorithm (EQT) was proposed. In this algorithm, in order to reduce the length of query command and communication overhead of the entire system, the reader uses the value of counter and the highest two collision bit as the parameter of query command, and tags only send the postfix of ID to the reader; In order to avoid idle timeslots and reduce the number of queries, EQT optimizes the identification process, which gets collision information of tags by sending the value of counter, and sends the query command. Simulation results show that the proposed algorithm significantly reduces the time complexity and communication overhead, and increases the throughput compared with other algorithms.