Selection combining hybrid FSO/RF systems over generalized induced-fading channels

Abstract A hybrid free space optical (FSO)/millimeter-wave radio frequency (mmWave RF) technology is a promising scheme to improve an optical link reliability and availability. In this paper, the performance of a selection combining hybrid FSO/RF system is investigated. The FSO link and mmWave RF link are modeled by the generalized Malaga ( M ) and η − μ distributions respectively. The effect of pointing errors as a result of misalignment between transmitter and receiver in the FSO link is also included. At the receiver, selection combining is considered to detect the link with the highest electrical signal-to-noise ratio (SNR). Moreover, closed-form expressions for the system performance in terms of the outage probability at high SNR and average bit error rate (ABER) for different binary modulation schemes are then derived for the FSO link, RF link and hybrid FSO/FSO systems. In addition, special cases in terms of Gamma–Gamma (GG), Nakagami-m fading distribution are obtained from the derived expression for the hybrid system. The security outage probability performance for the hybrid system is also determined by assuming that the channel of an Eavesdropper to the RF link undergoes Nakagami-m fading distribution. The results presented show that hybrid system can overcome the weakness of FSO links which are susceptible to atmospheric turbulence and pointing errors. Finally, the simulation results are presented to prove the accuracy of the derived expressions.