Performance of dual-hop FSO/RF systems with fixed-gain relaying over Fisher–Snedecor F and κ-μ shadowed fading channels

Abstract

We investigate the performance of a dual-hop mixed free space optical (FSO) /radio frequency (RF) system with fixed-gain relaying under direct detection and heterodyne detection techniques. The FSO link is modeled by the Fisher–Snedecor F distribution, which matches well with the experimental data under weak-to-strong turbulence regimes. The RF link experiences κ − μ shadowed fading, which unifies popular RF fading models. The κ − μ shadowed distribution is approximated by an α − μ distribution. Capitalizing on this approximation, closed-form approximate expressions for the cumulative distribution function, the average bit error rate of different modulation schemes, and the ergodic capacity are derived in terms of the bivariate Fox’s H function. Moreover, asymptotic analysis is carried out at a high signal-to-noise ratio to further illustrate the obtained diversity order and the influence of system and channel parameters. Numerical results and Monte Carlo simulations are presented to validate the derived approximate expressions.

Unified Performance Analysis of Dual-Hop Radio Frequency/Free Space Optical System

“…For example, at 𝛾̅ = 30 𝑑𝐵, ABER is 7.270 × 10 −5 , 4.926 × 10 −3 and 1.041 × 10 −2 for single FSO system from weak to strong atmospheric turbulence regions respectively. It also notes that asymptotic results derived in Equation ( 27) converge with the exact finding provided in Equation (23).…”

“…In literature, various fading models are used for RF and FSO channels in the relay-assisted dual-hop RF/FSO system including Rayleigh distribution [12][13] [14] [15], Nakagami-m [16][17] [18][19] [20], shadowed 𝜅 − 𝜇 [21] [22] [23] used for RF channel and Gamma-Gamma [12] [16][17] [20], Malaga, M [13], Double Generalized Gamma, DGG, [19] Exponentiated Weibull, EW, [18][21] 𝜅 − 𝜇 /Inverse Gaussian [14] and Fisher Snedecor, ℱ [15][21] [22] [23] used for FSO channel.…”

“…Higher-order quadrature amplitude modulations (QAM) and variable gain AF relaying techniques have been provided along with system parameters. [20] More recently, AF relaying scheme-based dual-hop system for different receiver detection techniques have been analyzed assuming RF /FSO link experienced by Rayleigh/ ℱ fading [15], RF /FSO link suffered by shadowed 𝜅 − 𝜇/ ℱ fading [22] and FSO/RF link modeled by ℱ/ shadowed 𝜅 − 𝜇 fading [23].…”

“…Figure8and Figure9demonstrate the ABER of the AF relaying system versus the average electrical SNR, 𝛾̅ given in Equation(23). Figure8shows the ABER under…”

A Review of Variable-Beam Divergence Angle FSO Communication Systems

“…In the existing studies, considering the aforementioned influencing factors, closed-form expressions of communication performance metrics such as OP and BER have been derived and simulated. This was achieved by deriving the expressions of probability density function (PDF) and cumulative distribution function (CDF) under different channel fading models, such as K distribution [12,13], Log-Normal distribution [14,15], Γ − Γ distribution [16][17][18][19], and generalized Málaga distribution [20,21], etc. The results demonstrate a strong dependence of performance indices on adjustable system parameters, such as beam divergence angle, transmitted optical power, and receiver's FOV angle [14,[21][22][23].…”