Coding for the Turbulent Atmospheric Optical Channel

In the presence of atmospheric or aircraft boundary layer turbulence, an optical channel may need large amounts of link margin to combat fading and beam spreading. Channel coding can reduce the average transmitter power required for reliable communication. This paper analyzes the performance of a coded PPM optical communication system that suffers log-normal fading during transmission. For moderate turbulence strengths, the coding gain in link margin is shown to be substantial.