Tiker A, Yarkoni N, Blaunstein N, Zilberman A, Kopeika N
Ben-Gurion University of Negev, Beer-Sheva, Israel.
Appl Opt. 2007 Jan 10;46(2):190-9. doi: 10.1364/ao.46.000190.
A unified approach for calculation of information data stream parameters in the atmospheric optical communication channel is presented based on irradiance fluctuations of optical wave propagation through turbulence and on a generalized Ricean K-parameter distribution. The effects of turbulence are described via the well-known Kolmogorov scheme of turbulent structure relaxation in terms of stochastic scintillation theory described by the gamma-gamma distribution along with measurements of the values of the refractive index structure parameter, C(n)(2). The relation between the Ricean parameter K and the signal scintillation parameter sigma(I)(2) is considered to develop a unified description of the corresponding probability density function (pdf) of signal fading within an atmospheric wireless communication link. Through the corresponding pdf and parameter K, signal data stream parameters such as the signal-to-noise ratio (SNR), bit error rate (BER), and capacity of the optical atmospheric channel (C) are estimated. Such an approach permits the reliable prediction of the effects of fading caused by different levels of turbulence and agrees with experimental data observed at different atmospheric levels, at the heights of both 100-200 m and above 1-2 km. It is shown that at heights of 100-200 m, effects of fading, caused by turbulence, occur much more frequently than those at the heights of 1-2 km. Data stream parameters such as channel capacity, SNR, and spectral efficiency become stronger at higher altitudes, while at the same time the BER becomes relatively negligible.
基于光波在湍流中传播的辐照度波动以及广义莱斯K参数分布，提出了一种计算大气光通信信道中信息数据流参数的统一方法。湍流的影响通过著名的湍流结构弛豫的科尔莫戈罗夫方案来描述，该方案基于伽马-伽马分布描述的随机闪烁理论以及折射率结构参数C(n)(2)的值的测量。考虑莱斯参数K与信号闪烁参数sigma(I)(2)之间的关系，以建立大气无线通信链路中信号衰落的相应概率密度函数（pdf）的统一描述。通过相应的pdf和参数K，估计信号数据流参数，如信噪比（SNR）、误码率（BER）和光大气信道容量（C）。这种方法允许可靠地预测由不同程度的湍流引起的衰落效应，并且与在不同大气水平、100 - 200米高度和1 - 2公里以上高度观测到的实验数据一致。结果表明，在100 - 200米高度，由湍流引起的衰落效应比在1 - 2公里高度更频繁地发生。诸如信道容量、SNR和频谱效率等数据流参数在较高海拔处变得更强，而同时BER变得相对可忽略不计。
