Pointing Errors Influence at the Performance of a Multi-hop Terrestrial FSO Link Emulated by a Dual-hop Scheme

The last years, FSO technologies raised interest from both scientific and commercial point of view. However, due to the optical beam propagation through the atmosphere, the signal is impaired by several phenomena like the scintillation effect, mainly because of atmospheric turbulence and imperfect misalignment between optical beam and destination terminal. In order to mitigate their negative influence, various countermeasures have been proposed. A well-known technique to preserve their performance over long distances is the employment of decode-and-forward (DF) relay nodes. Nevertheless, when the signal propagates over composite channels, characterized by atmospheric turbulence along with pointing errors effects, the employment of several DF relays increases significantly the complexity of the mathematical models used for performance evaluation. Motivated by this, we are trying to reduce the complexity of these expressions in the current work by replacing the multi-hop relay configuration via an equivalent dual-hop scheme. For first time, to the best of our knowledge, we are trying to emulate such an FSO system taking into account the simultaneous influence of both, atmospheric turbulence and pointing errors effects, in order to derive closed form mathematical expressions, which can be used in practice for the design of very fast optical wireless communication systems which can be used in the 5G/5G+ networks, mainly as backhaul communication links and support reliable their operation.