Analysis of subcarrier intensity modulation‐based optical wireless DF relaying over turbulence channels with path loss and pointing error impairments

Abstract

The authors consider a subcarrier intensity-modulated relayed optical wireless communication system under the combined influence of path loss, atmospheric turbulence and pointing error impairments. The turbulence-induced fading is modelled by independent but not necessarily identically distributed (i.n.i.d.) Gamma-Gamma fading statistics where the relaying protocol followed by the system is decode and forward (DF). First, the statistics of instantaneous signal-to-noise ratio at the destination is derived, followed by the novel and exact closed-form expression for outage probability of the system. Then using the moment generating function-based approach, the authors evaluate error performance of the system in terms of average symbol error rate (SER) for M-ary phase shift keying modulation schemes. Further, as a special case for M = 2, that is, binary phase shift keying modulation scheme, the exact closed-form expression of average SER is derived in terms of mathematically tractable Meijer's G-function and extended generalised bivariate Meijer's G-function. Finally, at the end of the paper, various numerical examples are included to demonstrate the effect of different system parameters on the performance of the system and are verified by Monte-Carlo simulations.

Ergodic Capacity of SIM-Based DF Relayed Optical Wireless Communication Systems

“…The analysis is done for moderate (C 2 n = 3 × 10 −14 ) and strong (C 2 n = 1 × 10 −13 ) turbulence [6] with the wavelength λ = 1550 nm and radius of receiver aperture r a = 1 cm which is half of receiver aperture diameter [9]. Without loss of generality, we take turbulence parameters for s − r and r − d links as α sr = α rd = α, β sr = β rd = β and ξ sr = ξ rd = ξ with average SNR per hop Ω sr = Ω rd = Ω.…”

“…The outage performance of DF relayed OWC systems have been analyzed in [4] over weak turbulence regimes with pointing errors. The error performance of DF relayed OWC systems in terms of average bit error rate (BER) and average symbol error rate (SER) has been studied in [5]- [6] using Gamma-Gamma distribution over strong turbulence channels. In [7], the ergodic capacity of AF relayed OWC system has been studied with the assumption that channel state information (CSI) is known only at the receiving terminals.…”

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

“…The first integrand,  1 , in (29) can be represented in terms of gamma function, Γ( ), defined earlier in (24), with value of = 1 2 , and the second integrand,  2 , can be computed using eq 2.1 from Shah, 30 as follows:…”

Exact MGF-Based Performance Analysis of Dual-Hop AF-Relayed Optical Wireless Communication Systems

“…The turbulence parameters α and β, both being greater than zero, represent the effective number of small-scale and largescale eddies of scattering atmosphere respectively and are given by [13] …”

“…The pdf of instantaneous SNR γ xy as defined in (2), is obtained by power transformation of (1) and is written using [13] as …”