【作者】 李倩；

【导师】 裴文江；

【作者基本信息】 东南大学 ， 信号与信息处理， 2016， 硕士

【摘要】 2.45GHz频段的RFID技术近年来得到快速发展,在物流管理、人员监控、船舶识别等领域有着广泛应用前景。由于RFID需求和标准的多样性和差异性,传统的测试仪器已不能满足实际应用需求,高性能的软件自定义实时测试仪器已成为一种必须。本文在PXIe模块化仪器硬件平台上,围绕2.45GHz频段的GB/T 28925 RFID标签一致性测试系统的设计与实现展开,主要研究工作如下：首先,对2.45GHz频段的RFID系统的工作原理进行了研究,阐述了RFID系统的基本框架以及采用半有源标签系统通信过程中所采用的关键技术。对于半有源标签提出了一种低频外部唤醒和微波频段利用反向散射调制原理传输数据的双频通信方案,并对O-QPSK 和 DBPSK两种调制方式进行了原理分析与仿真实现。接着,详细研究了GB/T 28925空中接口协议中物理层和数据链路层的关键技术,对于物理层,研究了阅读器与标签通信链路的工作频率、调制扩频方式以及信息速率等技术参数；对于数据链路层,研究了通信数据的组帧格式、消息数据格式、标签状态转移、常用通信命令集以及协议工作方式等；同时还详述了本文测试系统中实现的测试项需求与测试方法,为后续实现一致性测试系统奠定了理论基础。然后,完成了3B/T 28925 RFID一致性测试系统在PXIe模块化虚拟仪器平台上的实现,主要分为底层FPGA上RFID阅读器原型机和上层上位机测试模块两部分。介绍了测试系统的整体软硬件架构,采用时钟嵌套状态机的结构,实现了支持O-QPSK和DBPSK两种调制方式的RFID阅读器原型机；原型机主要包括物理层发射机、接收机和数据链路层三个部分。物理层发射机负责对命令数据的编码调制；接收机负责对接收基带信号的解调解码；数据链路层负责生成命令、分析响应以及控制命令交互,并将接收机解码后的数据传输至上位机。对发送和接收过程中的仪器驱动模块配置进行说明,并验证了FPGA底层原型机实时通信的正确性。最后,在RFID阅读器原型机的基础上完成测试模块的设计与实现,搭建完整的测试系统。测试模块实现了标签的射频与协议一致性测试,如联合时频分析、信号工作频率、占用信道带宽、信息速率、标签响应时间、标签命令响应以及标签状态转移的测试等,并对每个测试项都给出了具体的理论分析、程序说明和测试结果的显示。总之,本文设计了完全符合GB/T 28925空中接口协议规范的RFID标签一致性测试系统,该系统具备实时交互性、并行性、可扩展性和灵活性。更多还原

【Abstract】 2.45GHz RFID technology has been developed rapidly and proposed as the solution to problems in physical distribution management, man monitor and shipborne identification. Due to the diversity and difference of the RFID requirements and standards, traditional test instrument is unable to meet the demand of global industry, and a software-defined real-time test instrument of high performance becomes necessary. This paper is centered on the design and implementation of the GB/T 28925 RFID tag conformance test in 2.45GHz, which is based on the PXIe modular instruments platform. Main contributions are as follows:Firstly, the basic principles of RFID system working at 2.45GHz are studied in detail. We described the basic framework and key technologies in communication process of semi-active tag system. A dual band communication scheme is proposed for semi-active tag, which uses external awake signal at a low-frequency and backscatter modulation principle of data transmission at a microwave-frequency. O-QPSK and DBPSK modulation schemes are discussed, and simulation results are given afterwards.Secondly, the key technology of the GB/T 28925 air interface protocol is researched and illustrated. we research on the communication link between Reader and Tag, including operating frequency, modulation mode, data rate in physical layer and frame format of data, state transition of tag and protocol working mode in data link layer. We also describe the test requirement and test method of the RFID test system. This part has laid a theoretical foundation for implementing the conformance test system.Thirdly, the RFID test system based on the NI module instruments is constructed, including underlying FPGA RFID reader prototype and upper PC test module. With the clock nested state structure, we make a combination of physical layer transmitter, receiver and data link layer to realize the RFID reader prototype which supports two kinds of modulation as O-QPSK and DBPSK.At last, a complete test system is constructed by adding upper PC test module based on RFID reader prototype. Test module consists of tag RF and protocol conformance test, such as Joint Time-Frequency Analysis, code rate, tag response time, tag command response and tag state transition etc. Specific theoretical analysis, description of program and test results are given for each test module.In a word, the RFID conformance test system designed in this paper is real-time interactive, extensible and flexible.更多还原