Relayed FSO communication with aperture averaging receivers and misalignment errors

In this paper, 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 modeled via the exponentiated-Weibull distribution, which has recently been proposed to characterize 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. Further, 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 MGF-based approach. Finally, numerical examples are discussed and all the derived analytical results are corroborated by Monte-Carlo simulations.