Results of theoretical and experimental research of NLOS (NonLine of Sight) communication systems in the atmosphere, under water, and in mixed media based on publications of authors from China, Canada, Greece, the USA, Great Britain, Russia, and other countries are discussed in the present work. The theory of radiation transfer and the linear systems theory provide the basis for theoretical research. The radiation transfer equation is solved by the Monte–Carlo method in the singlescattering approximation. It is demonstrated that approximate methods are applicable when the average scattering multiplicity in open communication channels does not exceed 1.
The Monte Carlo method is used to study the influence of opticalgeometric parameters of schemes of communication channels on the probabilities of communication errors, signal/noise ratios, limiting base lengths, attenuation of informationcarrying signals, and their superposition leading to communication errors.
Examples of communications in the atmosphere in the UV range at distances up to 1300 m, in the visible range up to70 km, and under water up to 20 m are given.
Search for optimal methods of signal modulation, development of software and hardware complexes for numerical simulation of the transfer properties of communication channels, refinement of analytical models of impulse transfer characteristics of noncoplanar schemes of bistatic optoelectronic communication systems (OECS), and research of the effect of winddriven sea waves and processes of radiation scattering in water are planned to study the efficiency of operation of the communication systems and to expand ranges of variations of the input NLOS and OECS parameters in the experiments carried out in natural water reservoirs. 1. Lee I.E., Ghassemlooy Z., Ng W.P., Khalighi MA., and Liaw SK. Effects of aperture averaging and beam width on a partially coherent Gaussian beam over freespace optical links with turbulence and pointing errors//Applied Optics. 2016. Vol. 55, No. 1, pp. 1–9.
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• optical communication systems in the atmosphere and under water
• Monte Carlo method
• single scattering