水下光通信系统中的自适应数字化阵列接收技术研究
文献类型：学位论文
| 作者 | 胡秀寒 |
| 学位类别 | 博士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 朱小磊 |
| 关键词 | 水下光通信 阵列接收 自适应信号处理 蒙特卡洛仿真 马尔科夫链 |
| 其他题名 | Research of Adaptive Digital Array Receiving Technology in Underwater Optical Communication System |
| 中文摘要 | 本论文主要针对水下无线光通信（UWOC）的应用需求，对激光脉冲在水下传输后的特性进行了全面的仿真，改进了仿真方法，并基于仿真结果设计了通信系统，重点对系统中的控制电路和自适应阵列接收技术进行了研究，其中主要研究内容和创新点包括： 1）水下光学信道特性研究。利用蒙特卡洛（MC）法，通过仿真分析研究了激光脉冲在水下传输后的角度、时域、空域分布以及能量衰减情况，并研究了具有特定接收孔径和视场角的接收机接收到的脉冲能量和脉冲宽度。仿真结果作为理论基础指导UWOC系统的方案制定。 2）仿真方法的改进和创新。为了提高仿真精度，改进了MC法，在较少增加仿真时间的情况下明显提高仿真精度。基于改进的MC法，提出了半解析MC仿真法并推导了计算公式，可用于快速的估计系统的最大通信距离。另外，创新性地将马尔科夫链应用到了水下光传输仿真中，在计算接收面上的能量和时域分布时，可以显著降低仿真耗时，提高仿真速度。 3）长距离UWOC系统设计。根据MC仿真的结果，采用电光调制的倍频Nd:YAG脉冲激光作为光源，选用光电倍增管作为探测器，制定4路分集接收及信号合成方案，并采用自适应信号处理技术以保证通信的可靠性。 4）控制电路的软硬件实现。根据UWOC系统设计要求，设计并制成了控制电路，研究和编写其中的运行程序。检测和调试结果表明，控制电路可以完成实时全双工具有纠错功能的通信。 5）自适应阵列接收技术研究。在自适应信号处理方面，研究了均值滤波协同错位相减对脉冲定位精度提高的效果、软判决应对信号及噪声改变的能力，探测器自动增益控制方法及通信中脉冲丢失和重复时的处理方法。实验结果表明，控制电路具有良好的自适应性，能够很好地应对信号变化。在阵列接收方面，通过仿真和实验研究了4路信号合成对脉冲正确定位以及在弱信号提取方面的促进作用，结果表明，阵列接收和信号合成能够显著提高脉冲定位精度和信号提取能力。 |
| 英文摘要 | According to the application need of underwater wireless optical communication (UWOC), we simulated the performance of laser underwater propagation and developed new simulation methods. Based on simulation results, we projected a communication system and accomplished the design and fabrication of the main control circuit board. Besides, the adaptive digital array receiving technology is mainly studied. Several main research efforts and innovations are listed as follows: 1) Research of underwater optical channel. By Monte Carlo (MC) method, we simulated the energy, the angular, the temporal and the spatial distributions of laser after under propagation. And, the energy and the pulse width of a receiver with a certain aperture and field of view are also researched. The simulation results provided theoretical basis for the scheme design of UWOC system. 2) Modification and innovation of simulation method. To obtain better simulation accuracy, we modified the MC method. The modified method can achieve much higher simulation accuracy at the cost of a little increase of simulation time. Bases on the modified MC method, we proposed twice simulation method, which can be used to fast estimate the maximum communication distance of a UWOC system. What’s more, to decrease simulation time, we introduced Markov chain to underwater laser propagation simulation. The energy and temporal distribution of laser on receiving plane can be obtained through Markov chain method, with much less calculating time than MC method. 3) Design of long distance UWOC system. According to simulation results, we choose an electro-optic Q-switched frequency doubled Nd: YAG as light source. A photomultiplier with high sensitivity and gain is choosen as the detector. And, we adopted the receiving scheme of 4 channels diversity reception and signal synthesis. To ensure the reliability of communication, we decided to use adaptive adjustment technology. 4) Hardware and software implementation of main control circuit board in communication system. According to the demand of UWOC system, we designed and fabricated the main control circuit board. The calculation program are also studied and programmed. Test and debug results show that the main control circuit board can accomplish real-time full-duplex communication with error-correcting function. 5) Adaptive array receiving technology. In the adaptive adjusting aspect, we study the effects of average filtering and displacement differencing, the replying ability of soft-decision to changing signal and noise, the method of automatic gain control of detectors, and the handle method of the lose and the repeat of received laser pulse. Experimental results show that the main control circuit board has good adaptability. It can response the signal change well. In array receiving technology aspect, we conducted simulations and experiments to study the promoting effect of 4 channels signal synthesis on pulse positioning and weak signal extraction. Results show that, diversity reception and signal synthesis can obviously improve the accuracy of pulse positioning and the ability of signal extraction. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15909]  |
| 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 | 胡秀寒. 水下光通信系统中的自适应数字化阵列接收技术研究[D]. 中国科学院上海光学精密机械研究所. 2015. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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