尚光网 本站首页 本所首页 联系我们
chi20181130上海光机所陈卫标557452The blue-green spectrumis a low absorption band of seawater. The blue-green laser communication in seawater spectral window has the characteristics of high communication rate, good security and strong anti-interference ability. Compared with the free space optical communication in atmosphere, the underwater wireless optical communication channel is strongly affected by the absorption and scattering of water, which makes the pulse stretching and spatial expansion and energy attenuation of the optical signal, and the technical implementation is much more difficult than the free atmospheric optical communication.With the rapid development of ocean observation and utilization, it is more and more difficult to meet the growing communication rerquirements by the existing underwater communication methods. Underwater optical communication, with its corresponding high speed and appropriate distance transmission capacity, is becoming a hot research topic in the world. Aiming at the application requirements of underwater wireless optical communication system, in this thesis, the models and the numerical simulations for the channels of cross-medium and pure water are present, and the high code rate receiving algorithm and high sensitivity technologies are demonstrated. At same time, the software and hardware design and implementation of the control circuit in the underwater wireless communication system are conducted, and the receiving performance of the system is verified in a water tank, and results show the methods in thesis has the capability of high speed and high-sensitive for blue-green laser communication system. The main contents of this thesis are as follows: 1) The blue-green laser communication channel model is studied. Using Monte Carlo numerical simulation method, the model of the laser photon package transmission through atmosphere, the air-sea disturbance, and the underwater is setup. The model includes the effects of the scattering and attenuation, refraction and reflection at the boundary layer, and reception condition. In addition, using the established model, the laser spot distribution under different conditions is investigated, such as the pulse stretching, the influence of the field of view (FOV) and the receiving energy with receiver aperture. A cross-medium channel model and pure water channel model are used to illustrate the model calculation. The simulation results of the model were compared with experimental data to verify the accuracy of the model. 2) The blue-green laser communication system is designed. Based on the established blue-green laser channel model, the detailed design of high sensitivity and high speed system is given, including the selection of light source contrast, detector, and the receiving optical parameter, modulator, demodulator, encoder and decoder, and so on. 3) The key technologies of high sensitivity and high speed were studied. In order to meet the requirements of high sensitivity and high speed, the key technology of laser communication with high sensitivity and high speed is developed. Firstly, high sensitivity receiving technology of combining diversity receiving technology andphoton counting is demonstaed. Secondly, the effect of high speed rate due to intersymbol interference with on-off keying (OOK) modulation in long-distance underwater is investigated, and the improvement method using Viterbi equalization algorithm is proposed. 4) The performance is verified in the water tank experiment. The experimental scheme, experimental system parameters and channel parameters are described in detail. On the one hand, high-sensitivity photon counting experiment was carried out. The experiments are conducted to obtain the relationshop between the received photon count with distances and the received signal-to-noise ratio (SNR) with distance. The symbol-error rate (SER) was simulated based on this receiving situation and the SER result of photon counting experiment was obtained. On the other hand, the water tank experiment of the Viterbi equalization demodulation algorithm with high speed was carried out. The pulse stretching at different distances was obtained by using the analog detector, and the influence of the intersymbol interference (ISI) between diffetent communication data-rates were analyzed. Finally, the experminetal results with the Viterbi equalization demodulation algorithm was analyzed. The blue-green laser communication system with high sensitivity and high speed is expected to improve the specification of the underwater communication, which it is greatly significant for underwater observation netweork. The results in this thesis can provide references for the design and development of the long-distance high-speed blue-green laser communication system.2019atalunwen219129131735416Blue-green laser communication;Channel modeling;Diversity reception;Photon counting reception;Viterbi equalizationStudy of High Speed and High-sensitivity Blue-Green Laser Communication Technology高码率高灵敏度蓝绿激光通信技术研究蓝绿波段是海水的低损耗光学窗口,利用海水光谱窗口的蓝绿激光通信具有通信速率高、保密性好、抗干扰能力强等特点。相较于自由空间光通信,水下无线光通信信道由于受到水体的吸收和散射影响,使光信号在传输过程中发生时域和空域的展宽以及能量衰减,技术实现难度远大于自由空间光通信。随着海洋观测和利用的快速发展,现有水下通信手段已难于满足日益增长的通信需求,水下光通信凭借相应的高速大容量和适当距离传输能力,正成为国内外研究的热点。本论文主要针对水下无线光通信系统的应用需求,对跨介质激光传输和纯水下激光传输的信道链路进行了建模和仿真,对高码率收算法、接收高灵敏度策略进行了研究,同时完成了水下无线通信系统中控制电路的软硬件设计和实现,开展了水池试验验证系统的接收性能,旨在改善蓝绿激光通信性能,设计出高码率高灵敏度蓝绿激光通信系统。论文主要研究内容包括: 1) 开展了蓝绿激光通信信道模型研究。采用Monte Carlo数值仿真方法,详细描述了激光传输信道模型的光子包初始化、经过大气信道传输、经过海气界面的扰动、以及在海水信道中的传输模拟计算方法和流程,全程考虑了散射和衰减、在分层边界处的折射和反射以及接收条件限制等因素。并对已建立的模型进行分析,分析不同情况下的光斑分布,脉冲时域展宽,接收机视场角接收能量的影响以及接收机孔径对接收能量的影响。以跨介质信道模型和纯水下信道模型为例对模型进行计算说明。采用试验数据对比模型仿真结果,验证模型的准确性。 2) 开展了蓝绿激光通信系统设计研究。根据已建立的蓝绿激光信道模型,研究了高码率高灵敏度水下无线通信系统设计方案。给出了详细的高码率高灵敏度系统设计,包括光源对比与选择,探测器对比与选择,接收光学参数设计,调制器设计,解调器设计和编码译码器设计。 3) 开展了高灵敏度和高码率关键技术研究。针对高灵敏度和高码率要求,展开了高码率高灵敏度激光通信关键技术研究。首先研究了高灵敏度接收技术,主要包括分集接收技术,光子计数接收技术,光子数可分辨计数器设计和基于光子计数的分集接收机。其次研究了高码率接收技术,研究了长距离水下通信时在高码率OOK调制下的码间串扰的影响,以及采用Viterbi均衡算法后对接收性能的改善。 4) 开展了水池验证试验。为了验证系统的实际接收性能,开展了水池测试试验。介绍了试验方案,包括试验目的及方法,试验系统参数和信道参数。一方面开展了高灵敏度光子计数试验,包括不同距离下接收光子数统计,得到了不同距离下的接收信噪比,并基于此接收情况对误码率性能进行了仿真,最后给出了光子计数试验误码率结果。另一方面开展了高码率Viterbi均衡解调算法水池试验,利用模拟探测器获得了不同距离下的脉冲展宽情况,分析了在该码间串扰下对通信速率的影响,最后给出了Viterbi均衡解调算法水池试验结果。 高码率高灵敏度蓝绿激光通信系统有望提高蓝绿激光与水下目标通信的可靠性,对于海底观测数据传输具有重要意义,本论文研究成果可以为蓝绿激光与水下目标长距离高速通信系统的设计和研制提供参考。蓝绿激光通信;信道建模;分集接收;光子计数接收;Viterbi均衡中国科学院上海光学精密机械研究所胡思奇光学工程博士
中文题目: 高码率高灵敏度蓝绿激光通信技术研究
外文题目: Study of High Speed and High-sensitivity Blue-Green Laser Communication Technology
作者: 胡思奇
导师姓名: 陈卫标
学位授予机构: 中国科学院上海光学精密机械研究所
答辩时间: 20181130
中文关键词:
蓝绿激光通信;信道建模;分集接收;光子计数接收;Viterbi均衡
英文关键词:
Blue-green laser communication;Channel modeling;Diversity reception;Photon counting reception;Viterbi equalization
中文摘要:
英文摘要:
文献类型:学位论文
学位级别: 博士
正文语种: chi
全文传递服务
clickdetails
页面点击量: 31
文章下载量: 1
visitlog
友情链接:
  上海大恒公司
  南京先进激光技术院
  光学产品库
版权所有 © 2009 中国科学院上海光学精密机械研究所 沪ICP备05015387号
主办:中国科学院上海光学精密机械研究所 上海市嘉定区清河路390号(201800)