Performance evaluation of AF-relayed mixed FSO/mm-wave-RF link modeled by generalized misalignment and RF fading distributions

Abstract

The performance of a generalized mixed free-space-optical (FSO)/millimeter (mm)-wave radio-frequency (RF) two-hop link model is investigated in this work. The first-hop FSO channel considers the influence of path loss, atmospheric turbulence which is modeled by the gamma–gamma (GG)-distribution, and generalized misalignment errors which incorporate the effects of non-zero boresight errors, different jitter standard deviations along the horizontal and vertical directions, and correlation between the horizontal and vertical displacements. The second-hop RF link is modeled by an extended-generalized-K (EGK) distribution which is a versatile distribution and can characterize various fading conditions in mm-wave wireless channels where the transmission frequency is in excess of 60 GHz, and considers non-homogeneous propagation, interference effects due to multiuser transmission, multipath fading and shadowing effects observed in mm-wave RF wireless channels. The considered system employs fixed-gain amplify-and-forward (AF) relay-assisted transmission. The statistical characteristic for the end-to-end SNR, i.e., cumulative distribution function (cdf), is obtained for the considered system model in this work. Based on the obtained result for cdf, the outage and error performance is evaluated, and closed form expressions for the same are derived. The derived analytical results have been illustrated through numerical plots.