大规模RFID网络数据读取可靠性研究

发布时间：2018-01-03 17:37

本文关键词：大规模RFID网络数据读取可靠性研究　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

更多相关文章： RFID 阅读器 防碰撞 密集模式 CNRC

【摘要】：在科技快速发展的今天，物联网已经不再是新鲜的概念，而射频识别技术也随着物联网的发展，在物流、定位、食品溯源等多个方面得到了更为广泛的应用。RFID是一种非接触的无线通信系统，其通过射频信号将附着于物体上的标签所承载的信息发送给阅读器，从而完成对物体的自动识别或追踪等应用。伴随着RFID技术的发展，其相应的技术标准也日益得到完善，其中EPC global的C1G2标准在860MHz~960MHz的频段得到广泛认可。 RFID技术的一大特点是其具有快速的多目标识别能力，而与其它多种无线通信技术类似，由于受到无线信道频率和时序的限制，在具有多个阅读器或多个标签的系统中普遍存在着RFID碰撞问题。在大规模RFID网络中，信号碰撞的存在使得数据读取可靠性受到极大的挑战，本领域内的科研工作表明，稳定、高效且具有分布式处理能力的防碰撞算法对于提高大规模RFID网络数据读取可靠性有着重要的作用。根据应用环境不同，解决RFID碰撞问题，主要可以分为标签防碰撞算法和阅读器防碰撞算法两个方向。RFID的标签防碰撞算法主要包括基于ALOHA的PA算法、SA算法、FSA算法和基于二进制树形结构的SBT算法、BS算法、QT算法、CT算法等，另外还有多种基于以上算法的改进方案被提出。RFID的阅读器防碰撞算法则可以基于功率控制和中心控制分为两大类，其中，较为经典的基于中心控制的阅读器防碰撞算法包括Colorwave算法、HiQ算法以及Pulse算法等。经过对阅读器防碰撞算法前期的大量分析和研究工作，对大规模RFID网络数据读取可靠性问题有了深入的理解和认识，并基于此完成Colorwave算法的改进研究。论文在经典的阅读器防碰撞算法Colorwave的基础上，提出了一种基于图着色与非完全随机退避的Colorwave阅读器防碰撞改进算法——CNRC算法。主要创新内容如下： 1.提出基于图着色理论的CNRC算法轮内色数初值确定方法。即在初始阶段，基于基本图着色理论，确定CNRC算法执行色数初值，作为算法的输入变量之一。 2.提出碰撞阶段基于随机生成数比对的阅读器非完全随机退避机制。即在每次尝试传输之后，如果碰撞发生，阅读器即刻分别产生随机数，并进行对比，令产生最小随机数的阅读器颜色不发生改变，而其他阅读器正常执行随机退避机制。 3.提出增加控制信道作为阅读器间Kick命令转发的专用信道。即在Colorwave的数据信道基础上，增加了一条控制信道，作为专门用于Kick命令在阅读器之间发送的信道。算法实验部分，，在不同阅读器密度环境下，分别对系统平均吞吐率和延时比性能随系统运行时间和阅读请求发生率的变化完成了仿真验证分析，仿真实验证明，在大规模RFID网络所处的密集阅读器环境下，CNRC相对于传统阅读器碰撞算法性能更优，数据读取可靠性更高。
[Abstract]:In the rapid development of science and technology today, the Internet of things is no longer a new concept, and RFID technology with the development of Internet of things, in the logistics, positioning. Food traceability and other aspects have been more widely used. RFID is a contactless wireless communication system which sends the information carried by the tag attached to the object to the reader through radio frequency signal. With the development of RFID technology, the corresponding technical standards have been improved day by day. The C1G2 standard of EPC global is widely accepted in the band of 860 MHz. One of the characteristics of RFID technology is that it has fast multi-target recognition capability, but similar to other wireless communication technologies, it is limited by the frequency and timing of wireless channel. In the system with multiple readers or tags, RFID collision is a common problem. In large scale RFID networks, the reliability of data reading is greatly challenged by the existence of signal collisions. The research work in this field shows that the anti-collision algorithm, which is stable, efficient and has the ability of distributed processing, plays an important role in improving the reliability of data reading in large-scale RFID networks. According to the different application environment, the problem of RFID collision is solved. Tag anti-collision algorithm can be divided into two directions: tag anti-collision algorithm and reader anti-collision algorithm. RFID anti-collision algorithm mainly includes PA algorithm based on ALOHA and SA algorithm. FSA algorithm and SBT algorithm based on binary tree structure. In addition, a variety of improved schemes based on the above algorithms have been proposed. RFID reader anti-collision algorithm can be divided into two categories based on power control and central control. The classic anti-collision algorithm of reader based on central control includes Colorwave algorithm. HiQ algorithm and Pulse algorithm. After a lot of analysis and research work on reader anti-collision algorithm, we have a deep understanding and understanding of the reliability of large-scale RFID network data reading. Based on this, the improvement of Colorwave algorithm is studied. This paper is based on the classic reader anti-collision algorithm Colorwave. An improved anti-collision algorithm for Colorwave reader based on graph coloring and incomplete random Backoff is proposed. The main innovations are as follows: 1. Based on graph coloring theory, a method of determining the initial value of CNRC algorithm's inner chromatic number is proposed, that is, in the initial stage, based on the basic graph coloring theory, the initial value of the CNRC algorithm is determined to execute the chromatic number. As one of the input variables of the algorithm. 2. A partial random Backoff mechanism based on random number comparison in collision stage is proposed. That is, after each attempt to transmit, the reader produces random numbers immediately after each attempt, and compares them. The color of the reader that produces the minimum random number does not change, while the other readers normally perform the random Backoff mechanism. 3. An additional control channel is proposed as a special channel for Kick command forwarding between readers, that is, a control channel is added to the data channel of Colorwave. As a dedicated channel for sending Kick commands between readers. In the experimental part of the algorithm, under the different reader density environment, the performance of the average throughput and delay ratio of the system with the system running time and the rate of reading request are analyzed by simulation. The simulation results show that the performance of the collision algorithm is better and the reliability of data reading is higher in the dense reader environment of large scale RFID network than in the traditional reader collision algorithm.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TP391.44

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