【作者】 高蜀燕；

【导师】 张文爱；

【作者基本信息】 太原理工大学 ， 电路与系统， 2008， 硕士

【摘要】 RFID(Radio Frequency Identification),即射频识别,是一种利用无线射频方式在阅读器和标签之间进行非接触双向数据传输,以达到目标识别和数据交换目的的技术。射频自动识别技术在许多服务领域、在货物销售与后勤分配方面、在生产企业和材料流通领域等都得到了快速的普及和推广大大方便了对人流、物流的管理和信息的采集和统计,极大地提高了生产效率,方便了人们的日常生活。以射频识别为基础的电子标签技术研究与应用有着广泛的发展前景。论文的主要工作包括以下几个部分。1.射频识别技术的通信原理、系统构成、工作过程、关键技术等分析。2.介绍了RFID关键技术中的防碰撞算法原理及常用的防碰撞算法。3.本文设计了远距离有源RFID系统。该系统采用了Nordic公司的nRF24L01芯片作为系统的射频收发器。该芯片是一款功能强大的单片射频GFSK收发芯片,工作在2.4～2.5GHz全球开放的ISM频段,工作速率为0～2Mbps,最大发射功率0dBm。标签和读卡器分别采用了不同的MSP430芯片作为各自的主控制器。4.分析了项目中的防碰撞算法,实现二进制搜索算法的器件需要曼彻斯特编解码器,而nRF24L01采用的是GFSK编码方式,所以项目采用了ALOHA算法。针对ALOHA算法和时隙ALOHA算法,文章对其性能在参数大小不同的情形下进行了仿真,仿真结果表明:(1)时隙ALOHA算法比纯ALOHA算法无论在重发次数还是系统延时上系统性能都有明显改善。(2)对于任何一种算法,需要合理选择退避区间:退避区间太大,则标签数量较少时系统延时较大,退避区间太小,则标签数量较大时系统延时较大。退避区间的选择应该结合系统性能指标的要求来选取。5.在IAR公司的EW430开发环境下,开发了嵌入式软件。软件基本实现了项目预定的功能。更多还原

【Abstract】 RFID(Radio Frequency Identification) is a kind of technology which aim to achieve the target identification and exchange data .This technology use radio frequency to achive non-contact two-way data transmission between tags and readers.The radio frequency identification technology is fast popularized in many services, the freight distribution ,the rear service , the production enterprise and the material current, which greatly facilitated the management of the people and substance, and also make information gathering and the statistics convenient and enormously enhanced the production efficiency and facilitated people’s daily life. RFID-based research and application of electronic tagging technology has a broad rang of development.The main tasks of this paper include the following parts.1. Analysis of RFID communications mechanism, system structure, process, key technology, and so on.2. Introduction for the RFID technology in key anti-collision algorithm and the theory of popular anti-collision algorithm.3. Paper designed remote active RFID systems. The system uses the Nordic’s nRF24L01 chip as a sytem of RF transceiver, working in the 2.4 to 2.5 GHz the global open ISM band, rating of 0 to 2Mbps, the maximum emission power 0 dBm. Tags and readers were using different MSP430 chips as their main controller.4. Aanlysis of the projects in the anti-collision. The binery search algorithm requires Manchester codeing devices,but nRF24L01 using GFSK coding,so project adopte ALOHA algorithm. According to ALOHA algorithm and slot ALOHA algorithm, the article do simulation in the case of performance parameters of different sizes. Simulation results show that:(1) Slot ALOHA algorithm both in the number of re-issued and on the system delay has significantly improved for ALOHA algorithm.(2) For any of the algorithm, a logical choice backoff interval is needed. If backoff is too big, when the number of tag is little the system delay would be too large. If backoff interval is too little, when the number of tag is large sytem delay would be too large. Backoff interval should be choice according to the requirements of sytem performance.5.0n IAR’S EW430 development environment, paper develops embedded software. Embedded software implemente basic functions of the project.更多还原