Capacity And Probability Of Optical Wireless Communication System In Non-Kolmogorov Turbulence Channel

Wireless optical communication using the laser beam to transmit data, images, voice message in the atmosphere turbulent channel is a wireless laser communications technology. The particularity of wireless optical communication, it has so many advantages, such as high information, anti-electromagnetic interference and high security. In recent years, the rapid development of aviation and aerospace industries, people pay attention on the communication from satellite to terrestrial, satellite to satellite. The beam propagating in atmosphere turbulent channels must be affected by the turbulence. Therefore, the in-depth study of the propagation properties of the beam in atmospheric turbulence channel is not only theoretical significance, but also a practical guide value for the design of wireless optical communication system.This paper focuses on the affections of the turbulence intensity, the channel geometry parameters, beam jitter due to atmospheric turbulence, pointing error caused by transmitter base station and receiving platform jitter and other factors on the capacity of the signal in the non-Kolmogorov turbulence. Specifically includes, at first, discussed capacity of the Gaussian beam in moderate to strong turbulence conditions, use Gamma-Gamma distribution model to simulate the atmospheric turbulence channel, considered the light absorption of suspended particles in the channels, the path loss of beam propagation, beam wander due to the refraction of propagation beam caused by large scale eddies and the pointing error due to the building sway, obtain the capacity model in the channels under all the affection factors. Give the new variance of the pointing error and Gamma-Gamma distribution model. And then, discussed the capacity of the tilt channel in moderate to strong turbulence conditions, and correct the beam wander by using the short-term instead of long-term beam expansion, build the Gamma-Gamma irradiance distribution function corrected the beam wander and using the channel statistics model theory derived the capacity of the Gaussian beam in the tilt correction turbulent channel.The below main results: (1) when Gaussian beam propagates in non-Kolmogorov turbulent channel, the beam centroid will be effected by total aberration and tilt aberration. Of which: the beam centroid increase versus the zenith and spectral index in the total aberration channels, but the change of beam centroid position is very small in the tilt aberration channel, it can be neglect. Beam centriod increase versus the propagation distance. When the spectral index changes from 3.1 to 3.9, beam centroid position fluctuates in 0.2m-0.4m. (2) Capacity of the spatial Gaussian distribution of optical signals is affected by turbulence intensity, spectral index, wavelength and the receiver radius in the communication channels. With the increasing of propagation distance, the capacity shows a decreasing trend. In the same conditions, the capacity obviously decreases with the greater spectral index; when the propagation distance is constant, the capacity has a fluctuation versus the spectral index. The propagation distance is greater, the fluctuations are the stronger. The capacity decrease versus with the turbulence intensity. (3)The signal in the moderate turbulence channel with the tilt correction has a fluctuation in the propagation distance which is in the range of 0-7km. The average capacity gradually decreases versus with propagation distance that is greater than 7km. when the spectral indexα= 3.97, the capacity decrease the fastest with the increasing of propagation distance. The capacity decreases with the increasing of propagation distance in the strong turbulence condition.