便携式点对点可见光通信终端的实验研究  

Experimental study of portable point-to-point visible light commu nication terminals

作　　者：叶玮琳[1] 郑传涛[2] 张红伟[2] 吴祥坤[2] 

机构地区：[1]汕头大学工学院,广东汕头515063 [2]吉林大学,电子科学与工程学院,集成光电子学国家重点联合实验室吉林大学实验区,吉林长春130012

出　　处：《光电子．激光》2013年第8期1500-1506,共7页Journal of Optoelectronics·Laser

基　　金：汕头大学科研启动基金(NTF12022);汕头大学青年科研基金(YR12005);吉林大学大学生创新实验计划(2012C51186);吉林大学青年创新基金(450060487479)资助项目

摘　　要：利用开关键控-非归零码（OOK—NRZ）调制编码技术，设计并实现了一对基于ARM7处理器（LPC2148）的便携式点对点可见光通信（VLC）收／发终端。发送端由编码器、光源驱动器及单个白色发光二极管（wLED）构成，接收端由可见光探测器、信号处理电路及解码器构成。实验研究了WLED的发射谱和可见光探测器的响应谱，测试分析了VLC信道的时域和频域的电一光一电（EOE）响应。阐述了系统结构和原理，编写了通信软件并制定了相关协议，实现了系统的软、硬件集成。利用研制出的通信装置，建立了点对点通信链路，并开展了数据通信实验。结果表明，在发送端，为了最大化地降低误码率（BER），WLED的调制系数应设置为0．68～1．00，即在一定的交流调制信号幅度下，需要向WLED提供合适的直流偏置电压；在接收端，在一定的阈值判决门限电压下，VLC传输呈带通特性。在所优化选择的系统参数下，系统的通信距离为0．5m，可达到的最快信息传输速率约为4Mbps，BER小于10^-6。利用多个WLED构成阵列光源，系统可进一步满足更长距离的通信需求，从而在室内、外短途通信方面具有潜在的应用价值。By using on-off-keying （O OK） non-return-to-zero （NRZ） modulation and encoding technique, a pair of portable visible light communication （VLC） transmitter and receiver are designed and realized based on ARM7 processor （PLC2148）. The transmitter contains encoder module,light source driver and white light-emitting diode （WLED）,while the receiver includes VLC detector, signal processing circuit and decoder module. The spectral characteristics of WLED and VLC detector,as well as the time- and frequency-domain electro-optical-electro （EOE） responses of VLC channel are experimentally studied. The VLC structure and principle are described,the communication software and protocol are compiled, and both hardware and software are integrated. With the developed devices, the point-to-point VLC data- link is established, and data transmission experiment is performed. The results reveal that for the trans- mitter,in order to drop the bit error ratio （BER） to an acceptable level,a modulation coefficient within the range of 0. 68--1.00 is preferred, and a suitable bias voltage range is desired under a definite ampli- tude of alternative modulation signal, whereas for the receiver, under a certain threshold voltage, the VLC transmission presents band-pass characteristics. Under the optimized system parameters, the communication distance is about 0.5 m,the maximum bit rate is up to 4 Mbit/s,and the BER is less than 10-6. By using WLED array as light source, a longer communication distance can be system possesses potential applications for indoor and outdoor data links.

关 键 词：无线通信 可见光通信(VLC) 开关键控-非归零码(OOK-NRZ)调制 误码率(BER) 码元速率 

分 类 号：TH89[机械工程—仪器科学与技术]