Performance of an Amplify-and-Forward Dual-Hop Asymmetric RF–FSO Communication System

Abstract

In this work, the performance and the capacity analysis of a fixed-gain amplify-and-forward (AF)-based dual-hop asymmetric radio frequency-free space optical (RF-FSO) communication system is performed. The RF link experiences Nakagami-m fading and the FSO link experiences Gamma-Gamma turbulence. For this mixed RF-FSO cooperative system, novel and finite power series-based mathematical expressions for the cumulative distribution function, probability density function, and moment generating function of the end-to-end signal-to-noise ratio are derived. Using these channel statistics new finite power series-based analytical expressions are obtained for the outage probability, the average bit error rate (BER) for various binary and M-ary modulation techniques, and the average channel capacity of the considered system. The same analysis is also performed for the scenario when the FSO link undergoes significant pointing errors along with the Gamma-Gamma distributed turbulence. As a special case analytical expressions for the outage probability, BER, and channel capacity are also presented for a dual-hop asymmetric RF-FSO system where the RF link is Rayleigh distributed. Simulation results validate the proposed mathematical analysis. The effects of fading, turbulence, and pointing error are studied on the outage probability, average BER, and the channel capacity.

On the Performance Analysis of Dual-Hop Mixed FSO/RF Systems

“…In this section, we illustrate the mathematical formalism presented above and prove its correctness by means of MonteCarlo simulations using the system settings presented in Table I, which are employed in various FSO communication systems [4], [22], [28]. Specifically, we present the dual-hop system performance metrics for moderate and strong turbulence conditions as shown in Table II.…”

Experimental Investigation of All-Optical Relay-Assisted 10 Gb/s FSO Link Over the Atmospheric Turbulence Channel

“…Unlike fog, snow, and cloud, which induce attenuation, the atmospheric turbulence (AT), also known as scintillation, is the main source of random fluctuations of received optical radiation irradiance both in terms of intensity and phase variations even under the clear weather conditions [6]. A number of mitigation techniques have been investigated and proposed to combat the deterioration of signal quality due to adverse aforementioned atmospheric conditions including adaptive optics [7], spatial diversity [8], aperture averaging [9], modulation and signaling formats [10], coding [11], and hybrid RF/FSO systems [12], [13]. However, most of these mitigation techniques have the drawback of incurring high implementation complexity and/or cost.…”

Performance analysis of a variable‐gain amplify‐and‐forward relayed mixed RF‐FSO system

“…The end-to-end performance of a multiuser dual-hop decode and forward (DF) relaying system over mixed RF-FSO links is studied in Miridakis et al 10 The error performance of a fixed gain amplify-and-forward (AF) relay-assisted dual-hop mixed RF-FSO system with the RF link being Nakagami-m distributed and the FSO link characterised by gamma-gamma distribution is studied in Zedini et al 11 and Anees and Bhatnagar. 12 Other recent related works on mixed/hybrid RF-FSO systems and references therein can be found in Kong et al 13 and Zedini et al 14 A fixed-gain AF relaying protocol is simpler to implement as the channel state information (CSI) of the previous hop is not required. But it leads to variation in the signal power transmitted from the relay, because of its fixed gain.…”