Free Space Optics (FSO) or optical wireless communication is a promising solution for the need to very high data rate point-to-point communication. In FSO Communication links, the atmospheric turbulence causes fluctuations in both the intensity and the phase of the received light signal, impairing link performance. This intensity fluctuation, also known as scintillation is one of the most important factors that degrade the performance of an FSO communication link even under the clear sky condition. This paper investigates the use of multiple lasers and multiple apertures to mitigate the effects of scintillation. In the paper, the modulation format is Q-ary PPM across lasers, with intensity modulation. Ideal photodetectors are assumed, with and without background radiation. It is found that MIMO system provides significant performance not only under weak turbulence but also strong turbulence. The performance results are evaluated in terms of symbol error probability for several system parameters.
Advertisement
