大气对水平激光通信链路信号时域展宽特性研究
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摘要
自由空间光通信系统以其设备架构方便快速、大容量通信、高保密性等许多明显优于光纤通信系统的特点而成为国际研究的热点。其中水平激光通信链路利用激光在大气中传输来进行通信,激光信号将受大气影响而产生能量衰减,同时发生时域展宽。而激光信号的时域展宽是制约自由空间光通信系统通信速率的进一步提高的主要因素。自由空间光通信系统一般采用了IM/DD方式或者DPSK相位调制方式来进行通信,大气对激光信号造成的时域展宽现象在这两种方式下的影响分别表现为脉冲展宽和相位展宽。分析大气环境对光信号脉冲展宽与相位展宽的影响对提高水平激光通信链路性能具有重要意义。
本文针对大气对水平激光通信链路信号的时域展宽影响问题进行深入研究。基于大气散射过程对光信号在大气中的传输进行了理论分析和数值仿真。在此基础上针对强度调制和相位调制方式,讨论了大气传输距离、大气气溶胶粒子浓度和大气中信号传输初始角度等参数对信号展宽的影响,所做工作主要包括:
1、基于大气散射效应,建立光信号时域展宽理论模型,分别针对强度调制与相位调制方式分析信号时域展宽机理。
2、基于蒙特卡罗方法建立了水平激光链路光信号时域展宽效应仿真模型,改进了光子自由路径长度算法,提出了用具有正态分布模型的随机量散射系数βn来代替固定值β计算每一次光子的自由路径长度,使仿真结果更加符合实际情况。
3、针对强度调制方式下水平链路光信号时域展宽效应进行了理论分析和仿真研究,深入分析了大气传输距离、大气气溶胶粒子浓度和大气中信号传输初始角度等参数对激光信号时域展宽特性的影响。
4、针对相位调制方式下水平链路光信号时域展宽效应进行了理论分析和仿真研究,深入分析了大气传输距离、气溶胶粒子浓度和大气中信号传输初始角度等参数对激光信号时域展宽特性的影响。
本文的研究工作对于水平激光通信链路系统的设计与优化具有重要指导意义。
Free space optical communication system has quick architecture with its equipment, high capacity, high security and many other characteristics much better than optical fiber communication systems that it becomes an international research focus. Horizontal link laser optical communication system uses laser propagating through the atmosphere to communicate, its communication performance is influenced largely by the atmosphere, because the laser signal will be affected in the way of the energy attenuation and broadening occurred in the time domain and so on. The free space optical communication system’s further communication rate enhanced is restricted by the laser signal broadening in time domain. Free space optical communication systems generally use the IM/DD or DPSK phase modulation methods to communicate, under which modes the laser signal broadening in time-domain caused by the atmosphere were also different. Therefore, it is of great importance to study the impact of the laser signal broadening in time-domain caused by the atmosphere.
In this paper, we do the research on effects of the horizontal link of laser communication signal’s time-domain broadening caused by atmosphere. Monte Carlo simulation method is used to simulate the transmission of the laser signal in the horizontal link, and simulations are carried out respectively in pulse-width modulation and phase modulation. After that we discuss the parameters such as the transmission distance, the concentration of aerosol particles, the beam divergence angle on the signal broadening.
Research works are done by the following aspects:
1. Analyze the details of time-domain broadening of the laser signal generated by atmosphere, discuss the mechanism respectively in IM/DD mode and DPSK phase modulation mode.
2. In the design of Monte Carlo algorithm of the laser signal broadening in time domain, we improve the previous calculation of photon free path length, using a normal model of scattering coefficient as random volume instead of a fixed value to calculate each photon path length.
3. Implement Monte Carlo simulation of the laser signal broadening in time domain in IM/DD mode, and analyze parameters such as the transmission distance, the concentration of aerosol particles, beam divergence angle on the laser signal time-domain broadening respectively.
4. Implement Monte Carlo simulation of the laser signal time-domain broadening in DPSK phase modulation, and analyze parameters such as the transmission distance, the concentration of aerosol particles, beam divergence angle and the receiving aperture on the laser signal time-domain broadening respectively.
This research work has the instructible value to the design and optimization of horizontal link laser optical communication system.
本文针对大气对水平激光通信链路信号的时域展宽影响问题进行深入研究。基于大气散射过程对光信号在大气中的传输进行了理论分析和数值仿真。在此基础上针对强度调制和相位调制方式,讨论了大气传输距离、大气气溶胶粒子浓度和大气中信号传输初始角度等参数对信号展宽的影响,所做工作主要包括:
1、基于大气散射效应,建立光信号时域展宽理论模型,分别针对强度调制与相位调制方式分析信号时域展宽机理。
2、基于蒙特卡罗方法建立了水平激光链路光信号时域展宽效应仿真模型,改进了光子自由路径长度算法,提出了用具有正态分布模型的随机量散射系数βn来代替固定值β计算每一次光子的自由路径长度,使仿真结果更加符合实际情况。
3、针对强度调制方式下水平链路光信号时域展宽效应进行了理论分析和仿真研究,深入分析了大气传输距离、大气气溶胶粒子浓度和大气中信号传输初始角度等参数对激光信号时域展宽特性的影响。
4、针对相位调制方式下水平链路光信号时域展宽效应进行了理论分析和仿真研究,深入分析了大气传输距离、气溶胶粒子浓度和大气中信号传输初始角度等参数对激光信号时域展宽特性的影响。
本文的研究工作对于水平激光通信链路系统的设计与优化具有重要指导意义。
Free space optical communication system has quick architecture with its equipment, high capacity, high security and many other characteristics much better than optical fiber communication systems that it becomes an international research focus. Horizontal link laser optical communication system uses laser propagating through the atmosphere to communicate, its communication performance is influenced largely by the atmosphere, because the laser signal will be affected in the way of the energy attenuation and broadening occurred in the time domain and so on. The free space optical communication system’s further communication rate enhanced is restricted by the laser signal broadening in time domain. Free space optical communication systems generally use the IM/DD or DPSK phase modulation methods to communicate, under which modes the laser signal broadening in time-domain caused by the atmosphere were also different. Therefore, it is of great importance to study the impact of the laser signal broadening in time-domain caused by the atmosphere.
In this paper, we do the research on effects of the horizontal link of laser communication signal’s time-domain broadening caused by atmosphere. Monte Carlo simulation method is used to simulate the transmission of the laser signal in the horizontal link, and simulations are carried out respectively in pulse-width modulation and phase modulation. After that we discuss the parameters such as the transmission distance, the concentration of aerosol particles, the beam divergence angle on the signal broadening.
Research works are done by the following aspects:
1. Analyze the details of time-domain broadening of the laser signal generated by atmosphere, discuss the mechanism respectively in IM/DD mode and DPSK phase modulation mode.
2. In the design of Monte Carlo algorithm of the laser signal broadening in time domain, we improve the previous calculation of photon free path length, using a normal model of scattering coefficient as random volume instead of a fixed value to calculate each photon path length.
3. Implement Monte Carlo simulation of the laser signal broadening in time domain in IM/DD mode, and analyze parameters such as the transmission distance, the concentration of aerosol particles, beam divergence angle on the laser signal time-domain broadening respectively.
4. Implement Monte Carlo simulation of the laser signal time-domain broadening in DPSK phase modulation, and analyze parameters such as the transmission distance, the concentration of aerosol particles, beam divergence angle and the receiving aperture on the laser signal time-domain broadening respectively.
This research work has the instructible value to the design and optimization of horizontal link laser optical communication system.
引文
[1]殷致云. FSO广义信道特性研究[D].西安:西安理工大学, 2009: 1~3.
[2]马冬冬.无线激光通信系统中大气传输特性研究[D].西安:西安理工大学, 2009: 2~3.
[3] E. A. Bucher, R. M. Lerner. Some experiments on the propagation of light pulses through clouds[J]. Appl. Opt. 1970, 58(10): 1564~1567.
[4] E. A. Bucher. computer simulation of light pulse propagation for communication through thick clouds[J]. Appl. Opt. 1973, 12(10): 2391~2400.
[5] E. A. Bucher, R. M. Lerner. Experiments on light pulse communication and propagation through atmospheric clouds[J]. Appl. Opt. 1973, 12(10): 2401~2414.
[6] L. B. Stotts. Closed form expression for optical pulse broadening in multiple-scattering media[J]. Appl. Opt. 1976, 15(8): 1990~1995.
[7] C. Matter, G. Bradley. Optical pulse propagation through clouds[J]. Appl. Opt. 1981, 20(13): 2220~2228.
[8] W. H. Paik, M. Tebyani, D. J. Epstein. Propagation experiments in low–visibility atmospheres[J]. Appl. Opt. 1978, 17(6): 899~905.
[9] K. Shimizu, A. Ishimaru, L. Reynolds. Backscattering of a picosecond pulse from densely distributed scatterers[J]. Appl. Opt. 1979, 18: 3484~3488.
[10] K. Yasuo, A. Ishimaru. Experiments on picoseconds pulse propagation in a diffuse medium[J]. Opt. Soc. Am. 1983, 73(12): 1812~1816.
[11] G. C. Mooradian, M. Geller. Temporal and angular spreading of blue-green pulses in clouds[J]. Appl. Opt. 1982, 21(9): 1572~1578.
[12] G. C. Mooradian, M. Geller. Blue-green pulsed propagation through fog[J]. Appl. Opt. 1979, 18(4): 429~442.
[13] Majumdar. Transformation of statistical characteristics of picoseconds laser pulses by multiple scattering media[J]. Appl. Opt. 1986, 25(24): 4649~4656.
[14] K. Sunil, G. Zhixiong. Multidimensional Monte Carlo Simulation of Short-Pulse Laser Transport in Scattering Media[J]. Thermophysics and Heat Transfer. 2000, 14(4): 504~511.
[15] G. Zhixiong, A. Janice. Monte Carlo simulation and experiments of pulsed radiative transfer[J]. Quantitative Spectroscopy & Radiative Transfer. 2002, 73: 159~168.
[16] Z. Giovanni. Simple inexpensive method of measuring the temporal spreadingof a light pulse propagating in a turbid medium[J]. Appl. Opt. 1990, 29(27): 3938~3945.
[17] S. Ito, K. Furutsu. Theory of light pulse propagation through thick clouds[J]. Opt. Soc. Am. 1980, 70(4): 366~374.
[18] K. Debbie,S. Arnon. Evaluation of coherence interference in optical wireless communication through multiscattering channels[J]. Appl. Opt. 2006, 45(14): 3263~3269.
[19] S. Arnon, D. Sadot. Analysis of Optical Pulse Distortion Through Clouds for Satellite to Earth Adaptive Optical Communication[J]. J. M. Opt. 1994, 41(8): 1591~1605.
[20] W. O. Popoola, Z. Ghassemlooy. FSO communication in atmospheric turbulence using DPSK subcarrier modulation[C]. IEEE. CSND, 2008: 273~277.
[21] L. Jia, J. Q. Liu, D. P. Taylor. Optical communication using subcarrier PSK intensity modulation through atmospheric turbulence channels[C]. IEEE. Transactions on communications. 2007, 55(8): 1598~1606.
[22]狄凌峰,王沛.近地大气532nm激光散射的实验与计算[J].量子电子学报. 2005, 22(6): 960~964.
[23]杨虹,杨小丽.激光在云层信道中传输的蒙特卡罗模拟[J].激光杂志. 2008, 29(2): 44~46.
[24]任小红,韩香娥.激光在近地大气中水平传输特性研究[D].西安:西安电子科大. 2007.
[25]梁波,朱海,陈卫标.大气到海洋激光通信信道仿真[J].光学学报. 2007, 27(7): 1166~1172.
[26]贺细顺,朱晓.海水散射引起激光脉冲传输延迟的研究[J].激光与红外. 2001, 31(1): 19~21.
[27]徐祺瑞,尹福昌.激光在水下多径传输的蒙特卡罗模拟[J].长春理工大学学报. 2008, 31(1): 81~84.
[28]詹恩奇,王宏远.星载激光对潜通信的多径效应研究[J].华中科技大学学报. 2009, 37(2): 13~16.
[29]韩成,白宝兴,杨华民等.大气信道对激光脉冲延迟时间影响的仿真研究[J].光学学报. 2009, 29(8): 2046~2050.
[30]渠丽新,李晓峰.大气信道对激光通信信号散射脉冲展宽的研究[D].西安:电子科技大学, 2007: 103~105.
[31]宋雪平.云雾多次散射对激光散射信号生成的影响[J].红外与激光工程.
[32]吴健.随机介质中波场的双频双点互相干函数的窄带近似解[J].电波科学学报. 1996, 11(4): 27~30.
[33]吴健,刘瑞源.前向多重散射矩方程的解及其在电离层闪烁中的应用[J].中国科学. 1989, 12: 1322~1332.
[34]张民,吴振森,杨廷高.脉冲波在强起伏湍流介质中的传播特征分析[J].物理学报. 2001, 50(6): 1052~1057.
[35]李桂珍,吴健.适合随机电离层介质双频双点互相干函数的解[J].电波科学学报. 2003, 18(2): 157~160.
[36]谢小川.烟雾信道中光脉冲的传输特性研究[J].光电工程. 1991, 18(6): 33~38.
[37]许正文,吴健,吴振森.湍流介质中传播的脉冲时间展宽特性[J].中国科学. 2003, 33(2): 139~147.
[38]张洪江.大气湍流中激光波束和脉冲传输特性[D].西安:西安电子科大, 2009.
[39]方再根.计算机模拟和蒙特卡罗方法[M].北京:北京工业学院出版社. 1987:1~2.
[40]詹恩奇.光在大气和海水信道的传输性能研究[D].武汉:华中科技大学, 2007.
[41] L. G. Henyey and J. L. Greenstein. Diffuse radiation in the galaxy[J]. Astrophys. J. 1941, 93: 70~83.
[42] C. Bohren, D. Huffman. Absorption and Scattering of Light by Small Particles[M]. John Wiley and Sons. New York, 1983.
[43] T. Dominique. Henyey-Greenstein and Mie phase function in Monte Carlo radiative transfer computations[J]. Appl. Opt.1996, 35(18): 3270~3274.
[44] S. A. Prahl, M. Keijzer. A Monte Carlo model for Light Propagation in Tissue[J]. SPIE. Institute Series. 1989, 1(5): 102~111.
[45]齐鸣. DPSK信号解调及传输特性的研究[D].武汉:华中科技大学, 2007.
[2]马冬冬.无线激光通信系统中大气传输特性研究[D].西安:西安理工大学, 2009: 2~3.
[3] E. A. Bucher, R. M. Lerner. Some experiments on the propagation of light pulses through clouds[J]. Appl. Opt. 1970, 58(10): 1564~1567.
[4] E. A. Bucher. computer simulation of light pulse propagation for communication through thick clouds[J]. Appl. Opt. 1973, 12(10): 2391~2400.
[5] E. A. Bucher, R. M. Lerner. Experiments on light pulse communication and propagation through atmospheric clouds[J]. Appl. Opt. 1973, 12(10): 2401~2414.
[6] L. B. Stotts. Closed form expression for optical pulse broadening in multiple-scattering media[J]. Appl. Opt. 1976, 15(8): 1990~1995.
[7] C. Matter, G. Bradley. Optical pulse propagation through clouds[J]. Appl. Opt. 1981, 20(13): 2220~2228.
[8] W. H. Paik, M. Tebyani, D. J. Epstein. Propagation experiments in low–visibility atmospheres[J]. Appl. Opt. 1978, 17(6): 899~905.
[9] K. Shimizu, A. Ishimaru, L. Reynolds. Backscattering of a picosecond pulse from densely distributed scatterers[J]. Appl. Opt. 1979, 18: 3484~3488.
[10] K. Yasuo, A. Ishimaru. Experiments on picoseconds pulse propagation in a diffuse medium[J]. Opt. Soc. Am. 1983, 73(12): 1812~1816.
[11] G. C. Mooradian, M. Geller. Temporal and angular spreading of blue-green pulses in clouds[J]. Appl. Opt. 1982, 21(9): 1572~1578.
[12] G. C. Mooradian, M. Geller. Blue-green pulsed propagation through fog[J]. Appl. Opt. 1979, 18(4): 429~442.
[13] Majumdar. Transformation of statistical characteristics of picoseconds laser pulses by multiple scattering media[J]. Appl. Opt. 1986, 25(24): 4649~4656.
[14] K. Sunil, G. Zhixiong. Multidimensional Monte Carlo Simulation of Short-Pulse Laser Transport in Scattering Media[J]. Thermophysics and Heat Transfer. 2000, 14(4): 504~511.
[15] G. Zhixiong, A. Janice. Monte Carlo simulation and experiments of pulsed radiative transfer[J]. Quantitative Spectroscopy & Radiative Transfer. 2002, 73: 159~168.
[16] Z. Giovanni. Simple inexpensive method of measuring the temporal spreadingof a light pulse propagating in a turbid medium[J]. Appl. Opt. 1990, 29(27): 3938~3945.
[17] S. Ito, K. Furutsu. Theory of light pulse propagation through thick clouds[J]. Opt. Soc. Am. 1980, 70(4): 366~374.
[18] K. Debbie,S. Arnon. Evaluation of coherence interference in optical wireless communication through multiscattering channels[J]. Appl. Opt. 2006, 45(14): 3263~3269.
[19] S. Arnon, D. Sadot. Analysis of Optical Pulse Distortion Through Clouds for Satellite to Earth Adaptive Optical Communication[J]. J. M. Opt. 1994, 41(8): 1591~1605.
[20] W. O. Popoola, Z. Ghassemlooy. FSO communication in atmospheric turbulence using DPSK subcarrier modulation[C]. IEEE. CSND, 2008: 273~277.
[21] L. Jia, J. Q. Liu, D. P. Taylor. Optical communication using subcarrier PSK intensity modulation through atmospheric turbulence channels[C]. IEEE. Transactions on communications. 2007, 55(8): 1598~1606.
[22]狄凌峰,王沛.近地大气532nm激光散射的实验与计算[J].量子电子学报. 2005, 22(6): 960~964.
[23]杨虹,杨小丽.激光在云层信道中传输的蒙特卡罗模拟[J].激光杂志. 2008, 29(2): 44~46.
[24]任小红,韩香娥.激光在近地大气中水平传输特性研究[D].西安:西安电子科大. 2007.
[25]梁波,朱海,陈卫标.大气到海洋激光通信信道仿真[J].光学学报. 2007, 27(7): 1166~1172.
[26]贺细顺,朱晓.海水散射引起激光脉冲传输延迟的研究[J].激光与红外. 2001, 31(1): 19~21.
[27]徐祺瑞,尹福昌.激光在水下多径传输的蒙特卡罗模拟[J].长春理工大学学报. 2008, 31(1): 81~84.
[28]詹恩奇,王宏远.星载激光对潜通信的多径效应研究[J].华中科技大学学报. 2009, 37(2): 13~16.
[29]韩成,白宝兴,杨华民等.大气信道对激光脉冲延迟时间影响的仿真研究[J].光学学报. 2009, 29(8): 2046~2050.
[30]渠丽新,李晓峰.大气信道对激光通信信号散射脉冲展宽的研究[D].西安:电子科技大学, 2007: 103~105.
[31]宋雪平.云雾多次散射对激光散射信号生成的影响[J].红外与激光工程.
[32]吴健.随机介质中波场的双频双点互相干函数的窄带近似解[J].电波科学学报. 1996, 11(4): 27~30.
[33]吴健,刘瑞源.前向多重散射矩方程的解及其在电离层闪烁中的应用[J].中国科学. 1989, 12: 1322~1332.
[34]张民,吴振森,杨廷高.脉冲波在强起伏湍流介质中的传播特征分析[J].物理学报. 2001, 50(6): 1052~1057.
[35]李桂珍,吴健.适合随机电离层介质双频双点互相干函数的解[J].电波科学学报. 2003, 18(2): 157~160.
[36]谢小川.烟雾信道中光脉冲的传输特性研究[J].光电工程. 1991, 18(6): 33~38.
[37]许正文,吴健,吴振森.湍流介质中传播的脉冲时间展宽特性[J].中国科学. 2003, 33(2): 139~147.
[38]张洪江.大气湍流中激光波束和脉冲传输特性[D].西安:西安电子科大, 2009.
[39]方再根.计算机模拟和蒙特卡罗方法[M].北京:北京工业学院出版社. 1987:1~2.
[40]詹恩奇.光在大气和海水信道的传输性能研究[D].武汉:华中科技大学, 2007.
[41] L. G. Henyey and J. L. Greenstein. Diffuse radiation in the galaxy[J]. Astrophys. J. 1941, 93: 70~83.
[42] C. Bohren, D. Huffman. Absorption and Scattering of Light by Small Particles[M]. John Wiley and Sons. New York, 1983.
[43] T. Dominique. Henyey-Greenstein and Mie phase function in Monte Carlo radiative transfer computations[J]. Appl. Opt.1996, 35(18): 3270~3274.
[44] S. A. Prahl, M. Keijzer. A Monte Carlo model for Light Propagation in Tissue[J]. SPIE. Institute Series. 1989, 1(5): 102~111.
[45]齐鸣. DPSK信号解调及传输特性的研究[D].武汉:华中科技大学, 2007.