TMIA: A Tree-Based Multi-Reader Interactive Anti-Collision Algorithm for RFID Tag Identification

In the RFID system, the tag collision problem seriously affects the efficiency of tag identification. Among the anti-collision algorithms, tree-based anti-collision algorithms are popular for the reason that they can ensure that the tags can theoretically 100% be identified by readers. As multi-reader scenarios are more and more widely used in complex internet of things environments, there are more collision slots and idle slots in traditional anti-collision algorithms, which affects the efficiency of the algorithm. We propose a tree-based multi-reader interactive anti-collision algorithm (TMIA) for multi-reader tag identification scenarios to solve the problems above. Readers optimize the broadcast prefix sequence by sharing the broadcast results. The proposed algorithm works in two phases: In the first phase, the reader selects a suitable broadcast prefix by the multi-reader inverse probability function (MIPF) to reduce the initial redundant collision in tag identification. In the second phase, the priority of the broadcast prefix is adjusted through the information exchange between readers, the readers thus avoid broadcasting a large number of invalid prefixes. Theoretical analysis and simulation results show that TMIA has a lower total number of slots and better system efficiency than existing tree-based algorithms. TMIA also greatly reduce the number of collision slots.