采用ACO-OFDM调制新型可见光-射频识别标签系统

New kind of visible light-RFID with ACO-OFDM modulation

针对电磁波通信的传统射频识别标签系统有辐射,稳定性差的问题,提出一种采用非均匀限幅光正交频分复用调制(asymmetrically clipped optical-orthogonal frequency division multiplexing,ACO-OFDM)终端为数字标签的可见光通信系统。该系统将ACO-OFDM调制技术与可见光通信系统结合,对终端标签完成读写操作。为了提高可见光通信的稳定性,采用了ACO-OFDM调制提高了可见光信道的带宽利用率并且有效抵抗了信道间干扰,增强了可见光信道的稳定性。按照系统的设计分层,依次对终端标签芯片、调制解调、光发射机、接收机进行介绍。其中,终端标签芯片以及发射机,接收机电路基于UMC18 CMOS工艺流片,调制解调模块基于FPGA设计。仿真结果表明,该可见光射频识别标签系统的数字部分和模拟部分均能正常工作,实现了可见光对终端标签进行读写。

A new kind of visible light RFID system with Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (ACO-OFDM) modulation is proposed for concern over the radiative and unstable of the traditional radio frequency identification. The system combines ACO-OFDM modulation technology with visible light communication (VLC) technology to read tags. In order to improve the stability of the signal, ACO-OFDM modulation is implemented in the system to resist the intersignal interference and improve the bandwidth utilization. In the paper, we introduce the terminal tag chip, modem, optical emitter and receiver in turn. The terminal tag chip, emitter and receiver circuit have been implemented in 0.18μm CMOS process. The modulation and demodulation module is based on FPGA. According to the simulation, digital and analog part of the system can work properly and realize the operation to the tags.