基于优先级避让的防碰撞算法研究

摘要

针对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，而且可以较好地解决标签饥渴问题，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。%In order to alleviate the problem of tag starvation in the aloha-based algorithms,this paper proposed a new anti-col-lision algorithm based on priority aversion.The algorithm divided each identification round into two steps including of reserva-tion stage and identification stage.It assigned different tags to different priorities according to their hunger.In the reservation stage,a reader estimated the number of tags in collision slots by computing the collision factor.When the reader found two dif-ferent priority tags chose the same slot,it would inform the low priority tag to evade in identification stage.Theory and comput-er 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.