Adaptive multi-rate designs for hybrid FSO/RF systems over fading channels

This paper proposes a concept of adaptive multi-rate (AMR), which jointly employs switching between two links and adaptive rate on each link, for hybrid free-space optical/radio-frequency (FSO/RF) systems. Moreover, to support the operation of AMR, we propose the cross-layer design of AMR switching, which is based on both the physical and link layers with automatic-repeat request (ARQ) scheme. System performance metrics, including frame-error rate, goodput and outage probability, are analytically studied under the presence of atmospheric turbulence and Rician fading in FSO and RF links, respectively. Numerical results quantitatively show how the proposed systems significantly outperform conventional ones with physical layer-based design and/or fixed-rate switching operation.