【作者】 陈涛；

【导师】 徐成；

【作者基本信息】 武汉理工大学 ， 通信与信息系统， 2009， 硕士

【摘要】 RFID(Radio Frequency Identification),即射频识别,是20世纪90年代兴起的非接触式的自动识别技术,它通过射频信号自动识别目标对象并获取相关数据。RFID系统在货物跟踪和库存管理等供应链方面发挥了越来越重要的作用,为供应链管理提供了最便捷有效的实施方案。其应用包括产品认证、质量控制、仓储管理、物流供应、偷盗检测以及自动结账等诸多方面,而且未来RFID市场的潜力仍不可估量。RFID技术中无人工干预和可复用两大特点体现了它巨大的潜力和应用前景。随着RFID标签价格的进一步降低,RFID技术将更具优势和吸引力。本文围绕RFID系统防冲突算法展开研究。首先对RFID的发展历程、分类、特点、国内外研究和发展现状、以及实践意义和应用障碍、防冲突算法研究现状进行简单的介绍。在简单介绍了RFID系统结构和工作流程的基础上对其中的关键技术之一——标签防冲突算法进行重点讨论,概述了防冲突方案,对现有的两大类防冲突算法进行分析比较。进一步对ALOHA算法及其发展的算法进行仿真分析,在已有的随机算法的基础上提出了一种改进算法,并通过MATLAB仿真加以验证。论文的重点是第3章、第4章和第5章,对ALOHA算法的帧长及分组数提出了改进,详细分析和比较固定帧时隙ALOHA算法和动态帧时隙ALOHA算法;并针对读写器与标签通信时的防冲突问题设计了一个改进的动态帧时隙ALOHA算法。在标签数很多的情况下,通过估算现有标签数目,将标签分组,然后每组标签分别调用动态帧时隙ALOHA算法,通过估算每组中发生冲突的时隙数动态调整每帧时隙数,从而提高了系统效率,增强了系统的稳定性。在此基础上,应用MATLAB工具对改进算法进行了仿真,并对仿真结果进行了比较、分析,验证了模型的正确性和可行性。最后对本文的研究成果和存在的不足进行了总结和分析,为进一步研究提出展望。更多还原

【Abstract】 RFID (the Identification of the Radio Frequency), is a kind of automatic identification technology which has been developing since 1980s. It communicates and exchanges data bidirectionally and contactlessly through radio frequency for the purpose of identification. The RFID system is playing an important role in supply chain gradually, such as goods tracking, stock management, etc. The RFID system provides a most convenient and useful implementary project for the logistics supply chain management. Its application includes product authentication, quality control, storage management, logistics supply, stealing examination, automatic accounts settling, etc. However, the potential of RFID market still can’t be estimated in the future. Two greatest characteristics of RFID technique, unmanned work intervention and repeated use, show the huge potential and application foreground in RFID. With the further lowering of the price of RFID labels, the RFID technique will have more advantages and attractions.This thesis researches anti-collision algorithms of RFID system. Firstly, it introduces the development process, classification, characteristics, domestic and international present condition of research and development in RFID, the fulfillment meaning and the applied obstacle in management, present condition of studying anti-collision algorithms in RFID system briefly. Based on introducing the foundation of the structure and workflow of the RFID system briefly, it stresses to discuss one of the key techniques of RFID——anti-collision algorithm, summarizes the project of anti-collision, introduces two existing major types anti-collision algorithms, and carries on comparing and analyzing necessarily. Then it imitates ALOHA algorithm and other algorithms which come into ALOHA algorithm, improves the existent algorithms, and verifies the improved algorithm by imitating with MATLAB.Chapter 3 and chapter 4 are the key chapters in this thesis, it studies Class1 and Generation2 protocols which support to communicate between readers and tags, analyzes and compares the fixed frame slot ALOHA algorithm and dynamic frame slot ALOHA algorithm. Aiming at the anti- collision problem in communicating between readers and tags, an improving dynamic frame slot ALOHA algorithm is designed. Under the circumstances of many tags taking part in identification, the algorithm estimates existing the number of tags and groups, then each group transfers dynamic frame slot ALOHA algorithm respectively, estimates the number of collision slots in each group and adjusts the number of slots in a frame. Thus the efficiency of the system is raised and the stability of the system is strengthened. Besides, it models and imitates with MATLAB according to this project, and compares and analyzes the result of imitating, verifies the accuracy and possibility of the model.Finally, it sums up and analyzes the research contents and the shortage of this thesis, puts forward an outlook for further research.更多还原