Free space optical communication using OQPSK in the presence of strong atmospheric turbulence and losses.

Free space optical communication (FSO) is designed using the orthogonal quadrature phase shift keying (OQPSK) modulation technique. The system performance is evaluated for various levels of atmospheric turbulence, transmitter power, beam divergence, transmitter and receiver aperture diameters, and atmospheric losses. In this paper, we evaluated the system parameters for atmospheric turbulence using the Gamma gamma turbulence model. The system is evaluated for atmospheric losses such as clear air, medium-heavy rain, haze, and fog with various levels of atmospheric turbulence using the Optisystem Software tool for 1550 nm optical waves for SISO and MIMO OQPSK modulation. The obtained results show that the proposed model with OQPSK modulation and MIMO technology provides the best outcomes in terms of the BER, Q factor and received power. A link distance up to 3 km is achieved in the presence of atmospheric losses and turbulence. [ABSTRACT FROM AUTHOR]