Performance improvement of free space optical communication by extracting channel state information from the reference light

Here a reference light has been used to determine an instantaneous channel fading coefficient to extract the channel state information. Based on the fading coefficient, an optimal optical signal detection scheme is proposed so as to reduce the scintillation effect caused by the atmospheric turbulences. A BER analysis of the detected signal shows an improvement in the performance and the transmission distance. Further, a study has been made on the reliability of the proposed system based on the receiver´s aperture diameter followed by an analysis of the power margin required to maintain the reliability under different atmospheric turbulent conditions.