摘要： 随着超高频(UHF)频段射频识别(RFID)技术的广泛使用，使得RFID系统的研究者越来越关注对RFID物理层和MAC层特性的研究，以提高标签信息读取准确率、缩短读取时隙并增强协议安全性。但其前提是需要侦测及了解现有RFID协议通信过程及通信信息，获取底层数据，然而RFID阅读器只给用户提供上层结果。为解决RFID系统底层信息的获取问题，利用通用软件无线电外设被动侦测RFID系统无线通信信号，运用数字信号处理技术，设计并实现信息侦测平台。测试结果表明，该平台具有高接收灵敏度和解析准确度，UHF频段被动侦测距离最远可达8 m，优于已有侦测平台，并且对于被侦测信号的灵敏度为?115 dBm，侦测反应时间仅0.068 s，可抵抗常见无线信号干扰。

关键词: 射频识别系统, 被动侦测, 软件无线电, 数字信号处理, 信息提取, 物理层测试

Abstract: Ultra High Frequency(UHF) Radio Frequency Identification(RFID) systems are widely used, and the researchers focus on the characters of physical layer and Media Access Control(MAC) layer to enhance the reading accuracy, shorten the reading slots and ensure the security. It is primary to detect the existed RFID communication process and acquire the low-layer information, while the reader only provides the higher-layer results. To solve the problem of acquiring the RFID low-layer information, this paper presents the passive detection of wireless signal by Universal Software Radio Peripheral(USRP). The platform of information detection is realized through Digital Signal Processing(DSP). Test result illustrates the high receiving sensibility and analysis accuracy of the detection platform, and 8 m detection distance exceeds the other platforms. The sensibility of detection is ?115 dBm, the time of reaction is only 0.068 s, and the platform can resist the common interference of wireless signal.

Key words: Radio Frequency Identification(RFID) system, passive detection, Software-defined Radio(SDR), Digital Signal Processing (DSP), information extraction, physical layer test

中图分类号: 

• TN98