A collision-tolerant based anti-collision algorithm for large scale RFID system

Tag identification is an important issue in RFID system. Most existing anti-collision algorithms solely focus on reducing collision probability while suffering from vast idle slots. This paper proposes a collision-tolerant dynamic framed slotted Aloha (CE-DFSA) algorithm which attempts to identify multiple tags in a slot to reduce the total identification time in the process of identification. In CE-DFSA, tags are allocated with orthogonal Walsh Sequence (WS) so that multiple tags can be identified in a time slot without spreading the spectrum. Simulation results show that the proposed algorithm considerably accelerates the tag identification process with improved efficiency compared with existing anti-collision algorithms.