An Enhanced Anti-collision Algorithm for EPC Gen2 RFID System

Radio-frequency identification (RFID), a new technology for the contactless recognition of objects, is considered as an ideal solution to replace barcode systems. To make RFID technology widely applicable, it is important to resolve the "multiple tag identification problem," that is, indicating tag collision occurs when multiple RFID tags are simultaneously present in a reader\´s field. This paper discusses the dynamic framed slotted ALOHA (DFSA) algorithm adopted in EPCglobal\´s Gen2 standard and proposes an enhanced anti-collision algorithm based on the DFSA. In the proposed algorithm, a new command is added to the conventional DFSA algorithm for the purpose of 1) initiating a new round when tag collision or no-response (no signal from the tags) arises frequently and 2) adjusting the frame length according to the estimated number of tags in the field. The simulation results show that the proposed algorithm takes less tag identification time than the conventional DFSA, thereby increasing RFID system efficiency.