Outage Performance of Dual-Hop AF Relaying Systems with Mixed MMW RF and FSO Links

In this paper, we theoretically analyze the performance of a dual-hop fixed-gain amplify-and-forward (AF) system with mixed millimeter-wave radio-frequency (MMW RF) and free-space optics (FSO) links. The system is considered as a high-capacity, scalable and cost-effective backhaul solution for the 5G cellular-based vehicular networks. MMW RF and FSO channels are respectively modeled by the Ricean and Gamma-Gamma fading channels. Novel closed-form expressions for the end-to-end outage probabilities of the proposed system under various impacts of the transmission channels are analytically derived. Numerical results validate the mathematical analysis by Monte-Carlo (M-C) simulations and perform a comprehensive outage performance analysis of the proposed system.