An indoor FSO link under the weak turbulence regime: measurements and model validation

In this paper, we present the measurements performed on a free space optics (FSO) communications link using an indoor atmospheric chamber. In particular, we have generated several different optical turbulence conditions, demonstrating how even the weak turbulence regime can strongly affect the FSO link performance. We have carried out an in-depth analysis of the data collected during the measurements, and calculated the turbulence strength (i.e. scintillation index and Rytov variance) and the important performance metrics (i.e., the Q-factor and bit error rate) to evaluate the FSO link quality. Moreover, we have tested, for the first time, an appositely developed temporally-correlated Gamma-Gamma channel model to generate the temporal irradiance fluctuations observed at the receiver. This has been accomplished by using a complete analysis tool that enables us to fully simulate the experimental FSO link. Finally, we compare the generated time-series with the collected experimental data, showing a good agreement and thus proving the effectiveness of our model.