Relayed FSO communication with aperture averaging receivers and misalignment errors

In this study, the performance of decode-and-forward relay-assisted free-space-optical (FSO) communication systems under atmospheric turbulence-induced fading and misalignment errors is investigated. To mitigate the adverse effects of the atmospheric turbulence, the aperture-averaging receivers are considered both at the relay and destination sides. The atmospheric turbulence-induced fading is modelled via the exponentiated-Weibull distribution, which has recently been proposed to characterise an FSO link in the presence of finite-sized receiver aperture. The expression for the moment generating function (MGF) of the instantaneous signal-to-noise ratio is derived. Furthermore, new closed-form expression for the outage probability is obtained. Moreover, the new expression for the average symbol error rate of the subcarrier intensity-modulated M-ary phase-shift keying is obtained using the MGFbased approach. Finally, numerical examples are discussed and all the derived analytical results are corroborated by Monte Carlo simulations.