Further results on the capacity of free-space optical channels in turbulent atmosphere

Multihop Relaying Over IM/DD FSO Systems With Pointing Errors

“…where ξ i denotes the ratio between the equivalent beam radius at the receiver and the pointing error displacement standard deviation (jitter) at the receiver [1], [14] given as ξ i = wz eq ,i 2 σs,i , with σ 2 s,i is the jitter variance at the receiver and w zeq,i is the equivalent beam radius at the receiver [15], [16] (for negligible pointing errors, ξ → ∞),…”

“…All relay terminals simultaneously receive and transmit in the same frequency band, and no latency is incurred in the whole chain of 1 Note that, the PDF of Y given in (4) can also be represented in terms of the Meijer's G function by means of using [21, Eqs. (2.4.5), (2.1.4) and (2.9.1)] as…”

“…where γ i = η 2 I 2 i /N 0,i is the instantaneous SNR for the ith hop following the Gamma-Gamma model with pointing error impairments, with the PDF given by (1). It is noteworthy to mention that the derived equivalent SNR in Eq.…”

“…Free-space optical (FSO) communication has gained a significant research attention as a cost effective and wide bandwidth access technique operating at the unlicensed optical spectrum with high security level, relative to the traditional radio frequency (RF) transmission [1]- [3]. However, atmospheric pressure in the FSO links causes fluctuations in the refractive index, which is known as atmospheric turbulence, severely degrading the system performance particularly over distances of 1 km or longer [2].…”

“…However, atmospheric pressure in the FSO links causes fluctuations in the refractive index, which is known as atmospheric turbulence, severely degrading the system performance particularly over distances of 1 km or longer [2]. Moreover, building sway introduces vibrations in the transmitted beam, leading to a misalignment between the transmitter and the receiver, known as pointing error that limits the performance of FSO links [1], [4].…”