Research On Adaptive Modulation For Atmospheric Optical Communication

Atmospheric optical communication technology is a communication technology which takes atmospheric environment as channel and laser signal as carrier to realize long-distance wireless transmission.This technology has the characteristics of low cost,high speed and high bandwidth,and is the hot direction of development in the field of optical communication nowadays.Atmospheric environment is not a complete vacuum,and there are some factors such as atmospheric absorption,scattering,turbulence and so on.Especially under the action of moderate and strong turbulence,the performance of atmospheric optical communication system fluctuates greatly.This paper attempts to propose an atmospheric optical communication system using adaptive modulation technology,which can automatically select the best modulation mode for turbulent channel,in order to curb the bad shadow caused by atmospheric turbulence.Sound,enhance the stability of atmospheric optical communication system.In this paper,the research status of atmospheric optical communication system at home and abroad is summarized,and the research progress of modulation technology in atmospheric optical communication system in recent years is paid special attention to,and the research of atmospheric optical communication system and adaptive modulation technology is carried out.In the aspect of atmospheric optical communication system,the structure of atmospheric optical communication system is introduced.Mathematical model of atmospheric turbulence channel is established,and the probability of light intensity distribution in different intensity turbulence channel is accurately described.In the aspect of adaptive modulation technology,the commonly used modulation technologies such as OOK,PPM and SIM are introduced.An adaptive modulation system for atmospheric optical communication based on SIM-MDPSK technology is proposed.The bit error rate,spectrum efficiency and interruption probability of the adaptive system are analyzed in detail,which proves that the adaptive system is superior to the non-adaptive system.In the aspect of verification of adaptive system,the verification platform of adaptive modulation system for atmospheric optical communication is designed,and the modulation technologies such as 2ASK,2FSK,2PSK and 2DPSK are verified.