Passive RFID Tag Anti-Collision Binary Tree Slotted Protocol without Tags Quantity Estimation

In order to enhance the tag identification throughput of radio frequency identification (RFID) and reduce system computational complexity, this paper proposes three novel tag anti-collision protocols for a passive RFID system, i.e. dynamic binary tree slotted protocol, adaptive binary tree slotted protocol and splitting binary tree slotted protocol. The three proposed protocols all adopt binary tree slotted algorithm. In this algorithm, tags select random slots firstly. Then, if tags collide in a slot, the colliding tags will be resolved by binary tree immediately and the other tags will wait until the collision finishes. Further, the three protocols use a dynamic, adaptive and splitting method to adjust a frame length to a reasonable value for the number of tags, respectively. When the length of frame is close to the number of tags, system throughput will achieve a greater value. Thus, the proposed protocol will achieve a greater value. The advantage of the proposed protocols is that, they need not tag quantity estimation, and their throughput is not affected by variance of tag quantity. Computer simulation results show that the proposed protocols’ throughput can achieve 0.425, which is greater than conventional dynamic framed slotted aloha protocol and tree slotted aloha protocol with tag estimation. Also, the results show that the protocols’ throughput does not vary much when the number of tags increases from 5 to 1 000.