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题名	非视线光散射通信的若干基础问题研究
作者	冯涛
学位类别	博士
答辩日期	2007
授予单位	中国科学院上海光学精密机械研究所
导师	方祖捷
关键词	大气光通信 散射通信 非视线 大气散射
其他题名	Fundamental Research about Non-line-of-sight optical scattering communications
中文摘要	大气光通信技术是利用光作为载波，大气作为传输媒介的一种无线信息传输技术。它既可利用光束的直线传播进行视线通信，也可利用大气对光波的散射实现非视线通信。大气光通信，特别是非视线光散射通信在国防军事中具有重要的应用背景。本文针对非视线光散射通信的若干相关问题进行了基础性的理论和实验研究，同时也致力于实用化的视线大气光通信系统的开发。本文主要内容包括以下几个方面： 完成了一套小型化大气红外通信系统端机的研制。该系统工作在1.55m波段，端机尺寸为170mm160mm420mm，所有的有源光电器件与端机可分离安装，其间采用光纤连接，系统成本较低，并且易于安装、调试以及维护。该系统具有两个发射器一个接收器，可满足1km内无线高速数据传输的需求。 研究了非视线紫外光散射通信的传输模型和工作机制，对日盲紫外光的大气传输特性进行了研究和总结。在单次散射条件下，详细讨论了大气分子散射和气溶胶散射对非视线光通信的贡献。通过模拟计算，分析了非视线传输情况下，发射和接收仰角、光源发散角、接收视场等几何参数对接收散射光能量的影响。研究结果对于非视线光散射通信系统的设计是有指导意义的。 研究了大气能见度对非视线紫外光散射通信的影响。分析了低仰角发射情况下，非视线紫外光通信系统的最大比特率和所需平均发射功率随大气能见度的变化规律。结果表明，在能见度由高逐渐降低的相当大范围内，通信系统性能随能见度的变化并不明显；仅当能见度很低时，通信性能才会受到显著的影响。这与视线光通信是不同的。 研究了非视线光散射信道中光信号的多径传输问题及其对数字通信系统的影响。研究方法可用来评估非视线光散射信道的可用带宽，分析数字链路的码间干扰。该方法具有一般性，与通信系统的工作波长无关。 对非视线紫外通信系统的可行性和实现方案进行了初步的实验研究和分析。建立了基于紫外灯的语音和数字传输实验装置，并在上海光机所园区内进行了非视线通信实验，对其传输性能进行了测试。利用370nm的紫外LED进行了非视线传输实验，初步判断了利用紫外LED光源进行非视线通信的可行性。提出了一种采用脉位调制（PPM）的紫外激光通信系统方案。结合红外视线通信和紫外非视线通信的各自优点，提出了一种大气红外激光散射通信方案。
英文摘要	Atmospheric optical communication (AOC) has become a promising technology, which achieves wireless transmission of information through the light beam propagating in atmosphere. Line-of-sight (LOS) optical communication is based on the linear propagation of light beam, and light scattering by the atmosphere makes non-line-of-sight (NLOS) optical communication possible. Atmospheric optical communication, especially NLOS optical communication, is becoming a candidate for military applications in some particular situations. Some fundamental problems about NLOS optical scattering communication are investigated theoretically and experimentally in detail; and a practical AOC system is developed. The main contents of the thesis include the following points: The development of a LOS infrared wireless communication system is implemented. The system, with size of 170mm160mm420mm and low cost, operates at 1.55m, and facilitates the adjustment and maintenance. The system is designed with two transmitters and one receiver, and can meet the requirement for high data rate transmission within 1 km. Propagation model and operation mechanism of NLOS ultraviolet light scattering communication is studied, and propagation properties of solar-blind ultraviolet light in atmosphere is reviewed. Based on the assumption of single-scattering, contribution of atmospheric molecular scattering and aerosol scattering of received scattered energy is discussed. The model is used to analyze the correlations between received scattered energy and parameters of system, including source divergence angle, receiver field of view, and apex angles of transmitter and receiver. Dependence of performances of NLOS solar-blind ultraviolet communication systems on atmosphere visibility is investigated numerically by correlating propagation of UV radiation with the visibility. The effects of visibility on the attainable bit rate and required average transmitted power of NLOS optical communications operating at 266-nm are analyzed under low transmitter apex angle. The results indicate that the performance of the NLOS UV communication system is insensitive to variation of visibility in a quite large range, and deteriorate significantly only in the very low-visibility weather. This point is different from LOS optical communication. Multipath-induced pulse broadening in a NLOS optical scattering channel is investigated, and its influence on digital communication is also considered. The method proposed here can be used to predict available bandwidth of a NLOS optical scattering channel, and analyze the intersymbol interference induced by pulse broadening. The voice and digital links based on ultraviolet low pressure lamp has been set up, and their performances were tested in field. In order to judge the feasibility of ultraviolet communication based on LED, the experiment of NLOS light propagation is conducted by exploiting a 370nm LED source. A ultraviolet laser scattering communication system with pulse position modulation (PPM) scheme is proposed. In addition, a method of NLOS optical communication based on infrared laser is conceived.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15330]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	冯涛. 非视线光散射通信的若干基础问题研究[D]. 中国科学院上海光学精密机械研究所. 2007.

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