Effects of atmospheric turbulence on an optical communication system using a receiver with memory

Atmospheric turbulence causes random fading in any open-air optical communication channel. When the transmitted message is in the form of a block code, a binary union decoding system consisting of one storage register can be used to enhance the reliability of this type of fading channel. To illustrate the effectiveness of the binary union decoder, we compare probabilities of detecting one word out of N + 1 received words for both a binary union decoder and a simple word recognition decoder system. Finally, the binary union decoder is analyzed for three different fading conditions of the channel corresponding to conditions of atmospheric turbulence typical of weak, moderate, and superstrong scattering. Our findings show that the worst channel conditions for an optical communication system exist when the turbulence is moderate