非视距紫外光通信是近年来自由空间光通信的一个典型应用，其利用波长200-280nm之间的紫外光的“日盲”特性实现全天工作，利用大气粒子对光的散射实现非视距传输，是一种可非视距工作的光通信手段。论文研究非视距紫外光通信的调制解调特性，目的是获得高性能的调制解调方式，并找出提高紫外光通信性能的方法。主要研究成果如下： 阐述了紫外光大气传输特性，结合Lowtran软件分析了大气对紫外光的吸收和散射特点。研究了单次散射模型，论证了单次散射模型能够承担实际传输的相关计算，并利用蒙特卡罗方法对多次散射模型进行了模拟，得出了95%置信区间的传输特性。 研究了紫外光通信内调制和外调制的原理和特点，基于内调制原理对紫外光通信中OOK、PPM、DPPM、DPIM四种调制模式进行了研究，分析了平均发射功率、带宽需求、传输容量三个方面的优缺点，选择了PPM作为本论文紫外光调制模式。 分析了过零检测法、包络检测法、同步检测法三种解调方式理论及优点和缺点，结果表明同步检测法最适合紫外光通信解调。 利用MATLAB和Optisystem软件进行联合仿真，实现了OOK、PPM、DPPM调制解调的全过程，得出了PPM调制方式在误码率方面表现要优于其他方式。建立了基于Optisystem的紫外光通信实验系统，实现了OOK、PPM调制方式下的紫外光通信全过程，得出两种调制模式下的系统误码率眼图，再一次证明了PPM调制方式的优点。 研究了OFDM技术在紫外光通信中的应用，分析了OFDM技术高传输速率的可行性，建立了基于MIMO-OFDM紫外光通信实验系统，并作了理论论述。

Non-line-of-sight (NLOS) ultraviolet communication is an exciting application of free-space-optical (FSO) communication recently, it makes use of solar-blind ultraviolet as the communication wavelength to obtain all-day work, makes use of scattering of light by atmospheric particles to achieve NLOS propagation, and is an method of optical communication which can work at NLOS geometry. The main aims of this paper are to find a high performance modulation and demodulation way of ultraviolet communication, and to find a way to enhance the performance of ultraviolet communication. The main conclusions are shown as follows: This paper introduced the characteristics of ultraviolet atmospheric transmission, unified the Lowtran software to analyze the atmosphere to the ultraviolet ray absorption and the scattering characteristic.This paper has studied the single scattering model, proved the single scattering model to be able to undertake the actual transmission correlation computation, and has carried on the simulation using the Monte Carlo method to the multiple scattering model, has obtained 95% confidence interval transmission characteristic. This paper has studied principle several characteristics which are the ultraviolet optical communication intermodulation and outside modulates,based on the intermodulation principle to the ultraviolet optical communication in OOK, PPM, DPPM, the DPIM four kind of modulation patterns has conducted the research, has analyzed three aspect good and bad points which are the average emissive power, the band width demand and the transmission capacity, chose PPM to take the present paper ultraviolet light modulation pattern. Analysis the good and bad points of the cross zero detecting method, envelope detection method , synchronization detection method, three kinds of demodulation and the advantages and disadvantages, results show that synchronization detection method is suitable for ultraviolet communication. It has carried on the union simulation by using MATLAB and the Optisystem software, has realized OOK, PPM, the DPPM modulation demodulation entire process, obtained the PPM modulation way to display in the error rate aspect must surpass other ways.It has established ultraviolet optical communication experiment system which is based on the Optisystem to realized OOK, under the PPM modulation way ultraviolet optical communication entire process, obtained under two kinds of modulation patterns the system error rate eye chart, has proven the PPM modulation way merit again. This parper has studied the OFDM technology in the ultraviolet optical communication application, and has analyzed the OFDM technology high transmission speed feasibility, then has established based on the MIMO-OFDM ultraviolet optical communication experiment system, and has made the theory elaboration.