基于优先级避让的防碰撞算法研究

针对时隙随机分配的非确定性防碰撞算法可能出现的标签饥渴问题,提出了一种基于优先级避让的防碰撞算法。该算法将每一轮的标签识别过程分为标签预约和标签读取两个阶段,并根据标签在读写器作用范围内的驻留时间分配优先级。当预约时隙中出现碰撞时,读写器利用碰撞因子估计标签数量,当判断两个优先级不同的标签同时选择一个时隙时,优先级低的标签将在读取过程中主动避让,从而使对应的读取时隙避免碰撞。理论分析和仿真实验表明,该算法不仅可以有效减少碰撞时隙,提高系统的吞吐率,而且可以较好的解决标签饥渴问题,降低标签的漏检率,特别适用于标签数量大且对漏检率有严格要求的RFID系统。

Research on Anti-collision Algorithm Based on Priority Aversion

In order to alleviate the problem of tag starvation in the aloha-based algorithms, a new anti-collision algorithm based on priority aversion is proposed. Each identification round is divided into two steps including of reservation stage and identification stage in the new algorithm. Different tags are assigned to different priorities accord to their hunger. In the reservation stage, a reader estimates the number of tags in collision slots by computing the collision factor. When the reader finds two different priorities tags choose the same slot, it will inform the low priority tag to aversion in identification stage. Theory and computer simulations show that the new anti-collision algorithm can improve the throughput and reduce the missing rate, it is applied to RFID system where tags are high-speed and the number of tags is large.