无标签数估计的被动RFID标签防冲突二进制树时隙协议

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

为提高射频识别(radio frequency identification,RFID)标签的吞吐量并减少系统的复杂度,针对被动式RFID标签识别系统,提出了3种新的标签防冲突协议,分别是动态二进制树时隙协议、自适应二进制树时隙协议和分裂二进制树时隙协议.这3种协议均采用二进制树时隙的算法,即标签先随机选择时隙,如果发生冲突,则冲突的标签立即执行二进制树分解,而其余的标签等待,直到分解结束再识别等待的标签.其最大优点在于无需估计标签,可减少系统的复杂度,同时,又能保持较高的识别标签的吞吐量,而且吞吐量不受标签的变化影响.从仿真结果看,所提出的3种RFID标签防冲突协议的最大识别的吞吐量能达到0.425,高于传统的动态帧时隙Aloha协议、树时隙类Aloha协议,并且当标签在5～1000时,识别吞吐量未产生大的波动.

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.