Abstract: In order to solve the problem that tags can’t be identified quickly in the stochastic anti-collision algorithms, a novel hybrid anti-collision algorithm in RFID is presented. The novel algorithm adopting the FSA algorithm estimates the number of all unread tags directly according to the number of collided slots, and then changes the frame size dynamically several times to achieve the optical frame size. Then the reader will distribute the slots in terms of the optical frame size and make use of the ASM algorithm in collided slots to identify tags. Theory and simulations show that the new algorithm which is practical can improve the performance of system effectively, and make the slot throughput exceed 40%.

Key words: Radio Frequency Identification Devices（RFID）, anti-collision, Frame Slotted ALOHA（FSA） algorithm, optical frame size, Adaptive Search Matrix（ASM） algorithm, throughput

摘要： 针对射频识别（RFID）系统随机性防碰撞算法中标签识别效率低的问题，提出了一种新的RFID混合防碰撞算法。新算法采用帧时隙ALOHA（FSA）机制，根据碰撞时隙数直接估计出总的未识读标签数目，经多次动态调整帧长，获得最优帧长，然后使读写器按照最优帧长分配时隙以供标签响应，在碰撞时隙内调用自适应搜索矩阵（ASM）算法对响应标签进行识别。理论研究和仿真表明，新算法有效实用，可有效提高系统性能，使时隙吞吐量达到40%以上。

关键词: 射频识别, 防碰撞, 帧时隙ALOHA（FSA）算法, 最优帧长, 自适应搜索矩阵（ASM）算法, 吞吐量