Hybrid Blocking Algorithm for Identification of Overlapping Staying Tags Between Multiple Neighboring Readers in RFID Systems

Many algorithms have been proposed for avoiding tag collisions in radio-frequency identification (RFID) systems. However, most of these algorithms consider only a single reader in the current frame. Real-world Radio Frequency Identification systems typically contain multiple readers, and the interrogation zones of neighboring readers often overlap. This situation damages the performance of algorithms considering staying tags and each reader will ignore the overlapping staying tags due to counter states reset by other readers in the next frame. As a result, the efficiency of the tag identification process in the intersection region is seriously degraded. Accordingly, this paper analyzes the performance of three existing binary tree-based anticollision algorithms in detecting overlapping staying tags and then proposes a new hybrid blocking algorithm (HBA) to alleviate the overlapping staying tag problem. The simulation results show that the proposed HBA scheme provides a better identification performance than existing schemes, particularly, in dense RFID systems.