Optical communications over lognormal fading channels using OOK

We consider optical wireless communication systems over lognormal turbulence channels. Such systems can suffer from irreducible error floors when using on-off keying demodulation with fixed detection thresholds. The resulting error floors are analyzed for a nonzero extinction ratio. An electrical signal-to-noise ratio optimized detection system is introduced to eliminate the error floors, and such a system is designed for unknown turbulence environments. The bit-error rate performance of such a system is assessed for the lognormal fading channels.