Fading-loss assessment in atmospheric free-space optical communication links with on-off keying

Abstract

Link-budget calculations are a common way to assess system parameters, such as the required transmitter power and receiver sensitivity, in free-space optical ͑FSO͒ communication systems. One of the biggest challenges for long-range FSO deployment is its signal propagation under turbulent atmospheric conditions, which produce intensity fluctuations. Methods to estimate atmospheric-fading loss in radio-frequency systems cannot be adapted to the FSO channel. Until now no general closed-form methods have been developed to describe the fading loss in such a channel. A method to calculate the losses due to scintillation fading in the threshold approach, based on lognormal statistics of the received power, is presented.

Inverse Gaussian Modeling of Turbulence-Induced Fading in Free-Space Optical Systems

“…LN RVs. It should be noted that in the case of is given by [15] (11) However, there is no closed-form expression when . , the hypothesis is accepted with 95% significance until reaches the value of 0.35, which corresponds to the weak turbulence regime.…”

system aspects of optical LEO-to-ground links

“…The strength of this effect is quantified by the receiver Power Scintillation Index (PSI) (the normalized power variance), as depicted in Figure 9. From the PSI values, together with the assumption of lognormal fading of the power at the OGS, according to [21], one can estimate the loss a sci ( Figure 6) that has to be accounted for in the link budget calculation. Figure 6.…”

Mobile optical high-speed data links with small terminals

“…In [7] a simplified formula for calculating the IRT-losses in dB is given, which requires the received power scintillation index σ P 2 and the fading-threshold p thr as input.…”

“…Estimation of σ P 2 for an aeronautic downlink can be done by using formulas 2 and 12 of [7] (which are based on theory presented in [5]) as shown in the next figure. …”