基于DCO-OFDM的室内可见光通信系统发射机的实现研究

发布时间：2018-06-11 12:44

本文选题：室内可见光通信 + 白光LED　；参考：《南京邮电大学》2015年硕士论文

【摘要】：多径效应产生的码间干扰是影响基于白光LED室内可见光通信性能的主要因素之一,为了有效地抵抗多径效应,引入了正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)调制技术。当前的可见光通信系统是基于光强度调制,这意味着调制信号必须为非负的实信号,而OFDM信号是双极性复信号,不能直接在可见光通信系统中使用,因此在OFDM的基础上提出了DCO-OFDM调制技术。首先,论文讨论了可见光通信系统的概念及发展,并对白光LED的基本特性,包括发光机理、调制特性等进行了研究。接着,比较了发射机中采用的多种调制技术,分析了各自的优缺点,同时详细介绍了DCO-OFDM调制技术的基本原理。其次,介绍了FPGA的开发环境,对基于DCO-OFDM的VLC系统发射机各模块进行了研究与设计。发射机的调制模块采用DCO-OFDM调制技术,在基于ISE开发环境下,采用Verilog HDL硬件描述语言进行了各个模块的设计,包括映射模块、IFFT模块、添加循环前缀模块等等,运用ISE自带的仿真工具对设计的各个模块进行功能仿真,并根据系统软件的仿真结果进行分析。最后,讨论了LED的选型问题,并设计了LED的驱动电路和滤波放大电路,完成系统硬件的设计和搭建。论文工作的重点是系统发射机的DCO-OFDM调制部分的设计及驱动电路的硬件设计,该试验系统的实现为后续系统的进一步优化提供了一定的参考价值。
[Abstract]:The inter-symbol interference (ISI) caused by multipath effect is one of the main factors affecting the performance of indoor visible light communication based on white LED. In order to effectively resist the multipath effect, orthogonal Frequency Division Multiplexing (OFDM) modulation technology is introduced. The current visible light communication system is based on light intensity modulation, which means that the modulated signal must be a non-negative real signal, while the OFDM signal is a bipolar complex signal and cannot be directly used in a visible light communication system. Therefore, DCO-OFDM modulation technology is proposed on the basis of OFDM. Firstly, the concept and development of visible light communication system are discussed, and the basic characteristics of white LED, including luminescence mechanism and modulation characteristics, are studied. Then, several modulation techniques used in the transmitter are compared, their advantages and disadvantages are analyzed, and the basic principle of DCO-OFDM modulation technology is introduced in detail. Secondly, the development environment of FPGA is introduced, and the modules of VLC system transmitter based on DCO-OFDM are studied and designed. The modulation module of the transmitter adopts DCO-OFDM modulation technology. Under the development environment of ISE, Verilog HDL hardware description language is used to design each module, including mapping module, adding cyclic prefix module and so on. The functional simulation of each module is carried out by using the simulation tool of ISE, and the simulation results of the system software are analyzed. Finally, the selection of LED is discussed, and the driving circuit and filter amplifier circuit of LED are designed. The hardware of the system is designed and built. The emphasis of this paper is on the design of DCO-OFDM modulation part of the system transmitter and the hardware design of the driving circuit. The realization of the experimental system provides a certain reference value for the further optimization of the subsequent system.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN929.1

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