摘要近年来，被誉为下一代的绿色照明光源 LED 越来越受到人们的关注。LED 光源 拥有光照强度高、调制性能好、使用寿命长等诸多优点。基于 LED 光源调制性能好 的特点，人们提出了基于 LED 的室内可见光通信技术。将需要发送的信号通过一定 的调制，通过 LED 光源发射出的光传输出去。LED 光通信相较于传统的无线通信， 具有更高的传输功率，并且不会出现电磁干扰的问题。这种将照明与数据传输相结合 的 LED 光通信系统，非常适合用于家庭、办公室等室内场所。LED 光通信将是未来 室内通信的发展方向，具有广阔的前景。在本论文中，介绍了室内光通信系统的组成 以及相关的工作原理。重点介绍了室内光通信系统中的调制方式。首先大概的介绍了 开关键控调制（OOK）、脉冲位置调制（PPM）、波分复用技术（WDM）、正交频分 复用技术（OFDM），然后将开关键控调制和脉冲位置调制通过 Matlab 进行仿真。在 开关键控调制中，选用了归零和不归零两种调制信号对载波进行调制，通过分析比较 两种信号仿真出的波形图，得出结论：归零信号相较于不归零信号，占用带宽高，但 传输质量更好。在脉冲位置调制中，选用了 2-PPM 信号对载波进行调制，得出的结 论是 2-PPM 的传输质量与占空比为 1/2 的 OOK 效果相当，但使用 PPM 信号可以有 效的降低系统对平均功率的需求。在论文的最后对全文进行了总结与展望。79126

毕业论文关键字：LED；室内光通信；开关键控调制；脉冲位置调制

Abstract In recent years, more and more people pay attention to the next generation of green lighting LED。 LED light source has many advantages such as high light intensity, good modulation performance, and long service life and so on。 Based on the characteristics of the LED light source modulation performance, researchers put forward the indoor visible light communication technology based on LED。 The signal is needed to send through a certain modulation, and transmits through light emitted by the LED light source。 Compared with traditional wireless communication, LED optical communication has higher transmission power, and does not have the problem of electromagnetic interference。 This combination of lighting and data transmission LED optical communication system is very suitable for home, office and other indoor places。 It will be the future direction of the development of indoor communications and has broad prospects。 In this paper, the composition of indoor optical communication system and the related working principle are introduced。 The modulation mode of indoor optical communication system is introduced importantly in this paper。 First, introduction about the On-Off Keying, Pulse-Position Modulation, Wavelength-Division Multiplexing, Orthogonal Frequency Division Multiplexing, then On-Off Keying and Pulse-Position Modulation are stimulated by Matlab。 In On-Off Keying modulation, the selection of the waveform of Return-To-Zero and Non-Return-To-Zero signal modulated carrier, through the comparison of two kings of signal waveform and came to the conclusion。 Return-To-Zero compared to Return-to-Zero, it has high bandwidth, but the transmission quality is better。 In Pulse-Position Modulation, the selection of the waveform of 2-PPM signal modulated carrier。 It is concluded that transmission quality of 2-PPM is comparable to OOK that duty ratio is 1/2。 But use of PPM signals can effectively reduce the demand for the average power of the system。 Finally, it is summary and outlook of the full text。

Keywords: LED; indoor light communication; On-Off Keying; Pulse-Position Modulation

目 录

第一章 绪论 1

1。1 引言 1

1。2 国内外研究现状