甘青半干旱地区大气湍流对无线光通信的影响及信道估计方法研究

项目名称： 甘青半干旱地区大气湍流对无线光通信的影响及信道估计方法研究

项目编号： No.61465007

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 曹明华

作者单位： 兰州理工大学

项目金额： 47万元

中文摘要： 甘青半干旱地区由于日照时间长、降水量少蒸发量大、昼夜温差大和存在沙尘暴等因素，造成当地的大气湍流环境与国内其他地区有很大差异。而大气湍流导致的无线光通信接收端光强的起伏现象，会严重影响通信的有效性和可靠性。为此，本课题针对甘青半干旱地区的大气湍流，研究无线光通信系统受到的影响及其改善措施。依据湍流信道中光信号受到的影响，推导出该地区的光强起伏特性、脉冲展宽与时延，得到单光束传输时光强的概率分布函数；建立适合于甘青半干旱地区的湍流信道模型，并分析其性能；根据建立的信道模型，分别提出基于训练序列、隐训练序列和依赖数据的隐训练序列的光信道估计方案，并对其中的估计算法、训练序列的设计与选择、叠加训练序列的分离、最佳功率分配等关键技术进行研究。结合PPM调制信号的特点，提出改进方案。 该项目取得的研究成果为甘青半干旱地区无线光通信技术的应用与推广提供理论依据。

中文关键词： 无线光通信；大气激光通信；大气湍流；信道估计

英文摘要： The atmospheric turbulence environment of Gansu and Qinghai semi-arid areas is much different from that of other areas due to many factors, such as the long sunshine time, the precipitation deficit and a larger evaporation, the large temperature difference between day and night and repeatedly dust storms every year. It will seriously affect the validity and reliability of optical wireless communication by the turbulence caused intensity fluctuation phenomenon . Therefore, this project will investigate its influence to wireless optical communication systems and find some improving measures to overcome the atmospheric turbulence in the semi-arid area. According to the effect of optical signal in turbulent channel, we will derive the intensity fluctuation characteristics,the pulse spread and delay properties and the probability distribution function of single-beam optical transmission intensity in the semi-arid region; Establish a turbulent channel model suitable for the semi-arid area and analyze its performance. According to the established channel model, three kinds of optical channel estimation schemes will be investgated, which are training sequence scheme, superimposed training scheme and data-dependent superimposed training scheme. The key technologies like the estimation algorithms, the design of training sequence, the separation of superimposed training sequence and the optimal power allocation will be disscussed Moreover, we shall put forward the improvement scheme according to the characteristics of the PPM modulation signal. The achievements of this project will provide theoretical basis for the application and promotion for the wireless optical communication technology in semi-arid area of Gansu and Qinghai province.

英文关键词： wireless optical communication;atmosphere laser communication;atmosphere turbulence;channel estimation