FSO/RF correlation measurement and hybrid system hidden Markov model

The mean fade correlation between free space optical (FSO) and radio frequency (RF) channels is measured using experimental data collected from a 1550nm FSO and 37GHz RF, terrestrial links. The joint statistics of the FSO/RF channels under different weather conditions are simulated using a continuous density hidden Markov model (HMM) and shown to match real measurements for specific weather types. A two state hybrid FSO/RF channel simulator is used to extend the HMM to simulate the daily and seasonal variation of FSO/RF channels. Using the weather statistics of Adelaide, this simple two state channel simulator can predict the fading statistics of the hybrid channel for summer and winter seasons. The simulated results confirm that the proposed simulator can efficiently replicate the mean fade correlation and model the joint statistics of hybrid FSO/RF channels under various weather and meteorological conditions.