摘 要
可见光通信是随着第四代环保节能照明光源LED的发展而兴起的一种新型通信方式，随着白光LED的发明及应用，可见光通信技术得到了良好的发展。白光LED不仅可以提供室内照明，而且可以应用到无线光通信系统中满足室内个人网络需求。在照明方面，白光LED的节能、环保等特点被认为终将取代荧光灯、白炽灯等传统照明光源，成为下一代固体照明光源。与此同时，白光LED又具有响应时间短，加之其具有高速调制特性，可以设计出基于白光LED的室内可见光无线通信系统。由此设计出的基于白光LED的室内可见光无线通信系统，与传统的红外和了光无线电通信相比，具有发射功率高、无电磁干扰和无需申请频谱资源等优点。
论文主要对基于白光LED的室内可见光通信系统进行了研究。对白光LED的发光原理及工作特性做了较深入的分析。并研究了可见光通信系统的通信信道,对通信链路的构成进行了分析,给出了一种求LED照明灯室内布局的方法。介绍能量分布和多径效应的实验，通过测量可见光通信系统的空间光照度分布，重点研究了墙壁的反射作用和多光源引起的多径效应对系统性能的影响。因此，本文引入了一种基于正交频分复用(OFDM)调制与解调的方案，用于减弱高速通信时由多径效应带来的码间串扰。
关键词：可见光通信； 白光LED； 光照度分布； 多径效应； 正交频分复用
ABSTRACT
Visible light communication is with the development of the fourth generation of environmental protection and energy saving lighting source LED the rise of a new type of communication mode, with the invention and application of white LED, visible light communication technology obtained the good development. White LED can provide indoor lighting not only, and can be applied to the fso system meet the demand of indoor personal networks. In terms of lighting, energy saving and environmental protection characteristics of white LED is considered will eventually replace the traditional fluorescent lamp and incandescent lamp lighting light source, to become the next generation of solid lighting source. At the same time, white light leds have short response time and again together with its high speed modulation characteristics, can be designed based on white LED indoor visible light wireless communication system. The design of indoor visible light wireless communication system based on white LED, compared with the traditional infrared and radio communications, has high transmission power, no electromagnetic interference, and don't need to apply for spectrum, etc.
Thesis mainly based on visible white LED indoor optical communication system is studied. The luminous principle and working characteristics of white LED made a more in-depth analysis. And studied the communication channel of optical communication system, analyzes the composition of communication link, presents a LED light indoor layout method. Introduced the light energy distribution and multipath effect experiment, by measuring the visible light optical communication system of space distribution, mainly studies the wall reflection effect and multiple source caused by multipath effect will influence the performance of the system. Therefore, this article introduces a kind of based on orthogonal frequency division multiplexing (OFDM) modulation and demodulation scheme, when used for highway communication intersymbol interference caused by multipath effect.
Keywords:Visible light communication; White LED; Illuminance distribution; Multipath effect; Orthogonal frequency division multiplexing
