Convolutional Coded On-Off Keying Free-Space Optical Links over Fading Channels

The performance of Free Space Optical (FSO) systems reduces due to the presence of turbulence and misalignment effects. In this paper, we investigate the error control coding schemes as a candidate solution to mitigate turbulence and misalignment induced fadings over free space optical links. we have investigated for first time the error performance for coded onoff keying (OOK) optical wireless communication systems assuming intensity modulation/direct detection(IM/DD) represented by strong turbulence and pointing error effects. Specifically, we consider various combinations of channels assuming the existence of turbulence and/or pointing error effects and derive exact mathematical expressions for the pairwise error probability (PEP). By using this expressions upper bounds on the bit error rate (BER) are obtain using the transfer function technique. Then we calculate the error performance by using the pulse position modulation with different fading channels.