Effects of Adverse Weather on Free Space Optics

Nebuloni, Roberto; Capsoni, C.

doi:10.1007/978-3-319-30201-0_3

Cited by 9 publications

(9 citation statements)

References 31 publications

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“…Specific attenuation due to rain is independent of the wavelength in the optical transmission windows usually adopted by commercial FSO systems, which are the classical 0.780-0.850 and 1.520-1.600 µm bands [9]. For practical purposes, the specific attenuation γ (in dB/km) is often calculated from the rain rate R (in mm/h) through simple power-law relationships, i.e.,…”

Section: Specific Attenuationmentioning

confidence: 99%

“…In this case, the techniques used for turbulence mitigation are ineffective due to the correlation scale of the process (in both time and space). Fog has the most detrimental impact on optical waves: specific attenuation due to dense fog is as high as 300 dB/km for a visibility of around 50 m [9]. Rain attenuation, although markedly dependent on the microphysics of precipitation, is of the same order of magnitude as at mm-waves.…”

Section: Introductionmentioning

confidence: 99%

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Model for the Prediction of Rain Attenuation Affecting Free Space Optical Links

2018

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A model for the prediction of the attenuation induced by rain on free space optical (FSO) links is presented. The proposed methodology is developed, starting from the accurate simulation of the interaction between FSO links (path length up to 5 km) and precipitation maps, from which analytical expressions are then proposed. The model is simple as it only receives the local rainfall statistics for the site of interest as the input, but it is also accurate, as it takes into account the dependence of the attenuation on the drop size distribution (DSD), as well as multiple scattering effects associated with rain, which contributes to reducing the overall predicted attenuation. The proposed model represents a useful tool to dimension FSO links in areas where fog is negligible, i.e., where rain has the highest impact on the link performance.

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Section: Specific Attenuationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Model for the Prediction of Rain Attenuation Affecting Free Space Optical Links

2018

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“…The above empirical formula for the fog-related attenuation rate expressed in [dB/km] follows from the considerations discussed in [24], [33], [76]. Following [68], the visibility V (z) shown in Fig.…”

Section: Calculation Of Attenuation Along a Linkmentioning

confidence: 99%

Enhancing Resilience of FSO Networks to Adverse Weather Conditions

Kalesnikau

Pióro

Rak³

et al. 2021

IEEE Access

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This article is based on work from COST Action CA15127 ("Resilient communication services protecting end-user applications from disaster-based failures" -RECODIS), supported by COST (European Cooperation in Science and Technology); http://www.cost.eu The work of I. Kalesnikau and M. Pióro was also supported by the National Science Centre, Poland, under the grant no. 2017/25/B/ST7/02313, "Packet routing and transmission scheduling optimization in multi-hop wireless networks with multicast traffic" ABSTRACT Optical wireless networks realized by means of gigabit optical wireless communication (OWC) systems are becoming, in a variety of applications, an important alternative, or a complementary solution, to their fiber-based counterparts. However, performance of the OWC systems can be considerably degraded in periods of unfavorable weather conditions, such as heavy fog, which temporarily reduce the effective capacity of the network. In this paper, we focus on optical wireless mesh networks that use terrestrial links (called FSO -free-space optical -links) composed of several parallel full-duplex FSO systems, and present two complementary solutions that together provide a means to maximize network traffic performance in various weather conditions encountered during network operation. The first solution is a method for estimating the degradation of the effective FSO link capacity in adverse weather conditions such as fog, rain and snow (called the weather states in this paper). The second solution is an optimization model aiming at maximizing the network traffic throughput for a given list of weather states, derived from the conducted measurements. The model assumes the so-called affine flow thinning (AFT) traffic routing and protection mechanism capable of controlling the end-to-end traffic flows in response to fluctuations of capacity available on FSO links caused by changing weather conditions. The proposed link capacity modeling approach and the elaborated optimization model are verified through an exhaustive numerical study, illustrating the trade-off between the increase of traffic performance of the FSO networks and the corresponding cost of additional OWC systems.

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“…The visibility measured by the visibility sensors in Milan and Milešovka has been converted into specific attenuation by the above equation, which strictly holds at 0.550 μm (centre of the visible band). Basic scattering theory shows that minor differences in fog attenuation are expected when changing the operation wavelength from the visible to the first optical window (0.785-0.850 μm) and variations within 10% are expected when moving to 1.550 μm [15]. Besides (1), several empirical models have been proposed in the literature [16][17][18][19][20][21][22][23][24].…”

Section: Visibility To Attenuation Conversionmentioning

confidence: 99%

Estimation of optical attenuation in reduced visibility conditions in different environments across free space optics link

Dev

Nebuloni

Capsoni

et al. 2017

IET Microwaves, Antennas & Propagation

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Low‐visibility events detected in the city of Milan (Italy) and in the mountainous site of Milešovka (Czech Republic) during several months are analysed to compare optical attenuation measurements collected by a laser link and by a visibility sensor. General guidelines for data processing and automatic event identification are given. In Milan, the visibility sensor is a valuable support to estimate link attenuation during moderate radiation fogs or when it is raining, provided data are averaged in time. In Milešovka, the propagation conditions are challenging and the effect of the inhomogeneous distribution of fog (cloud) limit the usefulness of visibility measurements. In the case of snowfalls, that can produce high‐attenuation values, the agreement between the two measurements is poor.

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Effects of Adverse Weather on Free Space Optics

Cited by 9 publications

References 31 publications

Model for the Prediction of Rain Attenuation Affecting Free Space Optical Links

Model for the Prediction of Rain Attenuation Affecting Free Space Optical Links

Enhancing Resilience of FSO Networks to Adverse Weather Conditions

Estimation of optical attenuation in reduced visibility conditions in different environments across free space optics link

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