面向室内吉比特通信的实时RGB-LDs可见光通信的关键问题研究

Visible light communication for both indoors luminescent white-lighting and optical wireless communication has recently been a research spotlight for future multi-gigabit indoor communication. However, there are some problems such as low speed data rate and transmission performance in current real-time visible light communication. In our previous work, we have experimental demonstrated a real-time visible laser light communication system based on orthogonal frequency division multiplexing. Based on it, in the project, a real-time orthogonal frequency division multiplexing visible light communication based on Red-Green-Blue laser diodes(RGB-LDs) is proposed. And the generation scheme of white-lighting is investigated for both indoors luminescent and high-speed optical wireless communication. In order to investigate the transmission performance of real-time orthogonal frequency division multiplexing signal over free space channel, mathematical models for optical transmitter and receiver and free space channel are developed. Using these models, the transmission performance of real-time orthogonal frequency division multiplexing signals over free space channel transmission is evaluated. In addition, efficient digital signal processing algorithms are proposed to improve the transmission performance of real-time orthogonal frequency division multiplexing visible light communication system. Moreover, a real-time transceiver can be implemented for high-speed real-time orthogonal frequency division multiplexing visible light communication system based on Field-Programmable Gate Array. In a word, these innovation works in the project can be done to improve the integration of real-time orthogonal frequency division multiplexing signals and visible light communication technology for multi-gigabit indoor communication in practical.

兼顾照明与通信的可见光通信是提供室内吉比特通信极有潜力的方案。目前，实时可见光通信速率局限于Mbit/s，如何提高实时可见光通信的速率和传输性能且满足照明要求成为亟待解决的重要课题。申请人课题组已实现基于蓝色激光二极管的吉比特速率实时正交频分复用可见光通信，在此基础上，本项目提出一种基于红绿蓝三色激光二极管(RGB-LDs)的实时可见光通信系统，研究能提供吉比特通信和照明的白光产生方法；建立理论模型分析吉比特实时正交频分复用可见光信号在自由空间信道受路径损耗和多径时延的影响，提出新的符号同步算法、信道估计与补偿算法来优化信道损伤和非线性损伤；基于可编程逻辑门阵列硬件实现吉比特实时可见光通信的收发机，对提出的算法进行实验验证和优化。本项目拟实现适于室内吉比特通信的低成本实时可见光通信系统，为促进实时可见光通信与室内宽带接入的融合提供理论和应用参考。

在国家基金的支持下，围绕吉比特可见光信号的产生和自由空间信道传输，以及适于吉比特实时正交频分复用可见光通信的信号处理技术等一系列问题，本项目组按照申请书的计划开展研究工作，并取得了预期的研究成果，这些成果都通过实验验证，包括：研究吉比特实时可见光信号在自由空间信道的传输性能；提出适于吉比特实时可见光通信的信道估计算法、盲均衡算法以及频率偏差估计与补偿算法来优化信道损伤和非线性损伤；基于可编程逻辑门阵列硬件对关键数字信号处理算法进行实验验证，实现了吉比特实时正交频分复用可见光通信系统。这些研究工作表明，采用提出的比特交织极化码编码调制、高阶调制、自适应调制和多输入多输出相结合的方法可提高可见光通信系统的传输性能和频谱效率。提出的简单的采样频率偏差估计算法易于可编程逻辑门阵列硬件实现，有利于实时实现吉比特正交频分复用可见光通信。提出的软件可配置的动态功率与子载波分配方法，以及基于功率域非正交多址接入技术的有线与无线信号的复用，可实现室内光无线混合接入系统，提高系统容量与灵活度，同时能够保证用户公平性，为促进实时可见光通信与室内宽带接入的融合提供了理论和应用参考。本项目组发表SCI收录论文20篇（其中SCI二区论文10篇），EI收录的会议论文5篇（其中OFC国际会议论文2篇），申请了国家发明专利3项。培养博士生4名，硕士生8名。项目组成员邓锐的博士学位论文被评为“湖南大学优秀博士学位论文”。项目组成员李之其的硕士学位论文被评为“湖南省优秀硕士学位论文”和“湖南大学优秀硕士学位论文”。