多径衰落信道下射频识别系统抗干扰技术

摘要

射频识别(RFID)系统通信环境由简单近距离的室内通信向复杂远距离的都市通信发展，在读写器和电子标签之间出现了由多径效应引起的带多普勒频移的瑞利衰落。针对 B 类标签信号在多径瑞利衰落信道中的传输进行系统建模与分析，并将正交频分复用(OFDM)系统引入以提高 RFID信号对信噪比的敏感度。仿真结果表明，标签信号在多径瑞利衰落信道中对信噪比变化不敏感，引入 OFDM后信号对信噪比的敏感度明显提高，RFID系统抗干扰能力得到增强。%　　With the communication environment of Radio Frequency Identification(RFID) system developing from near field communication to long distance communication,Rayleigh fading with Doppler frequency shift emerges due to multipath effect between the readers and electronic tags. A systemic study is focused on modeling and analysis of channel transmission for type B tag signals in the multiple Rayleigh fading channel. The OFDM system is added to the RFID tag signals to improve the sensitivity of SNR in the Rayleigh fading channel. The research results show that SNR of tag signal is not sensitive in the multipath Rayleigh fading channel. However, the sensitivity has increased after OFDM adding to the RFID system and the anti-interference ability has been highly improved.