ASER Performance Analysis of Decision Threshold-Based Hybrid FSO-RF Turbulent Link

In this paper a novel hybrid Free Space Optical (FSO)-Radio Frequency (RF) model is proposed which is based on the single decision threshold feedback bit technique. The FSO and proposed hybrid FSO-RF link performance is investigated under strong turbulence and misalignment aperture error or pointing error in terms of the average symbol error rate (ASER) and outage probability. Atmospheric turbulence and misalignment aperture are foremost factors that affect the performance of FSO link which entails the requirement of an RF link as a backup to enhance the system performance. The FSO-RF link is preferred in this work over the normal FSO link due to ease in switching among the link established with the help of decision threshold during failure of FSO link. In this proposed hybrid model, Gamma-Gamma distribution is considered as free-space optical turbulence channel and Nakagami-m model is for RF link. The analytical expressions for outage probability, ASER have been derived and results are given for various Subcarrier Intensity Modulation—M-Phase Shift Keying (PSK) schemes. A performance comparative study is reported for FSO link and hybrid FSO-RF link. The obtained result indicates the enhanced system performance whereas the obtained results are validated through Monte-Carlo simulations and results are found in good agreement.