A Collision-Tolerant-Based Anti-Collision Algorithm for Large Scale RFID System

Tag identification is an important issue in an RFID system. Most existing anti-collision algorithms solely focus on reducing collision probability while suffering from vast idle slots. This letter 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 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.