A Novel Piecewise Atmospheric Attenuation Model for Free Space Optical Links in Vertical Heterogeneous Networks

TL;DR

This paper introduces a comprehensive piecewise atmospheric attenuation model for free-space optical links in vertical heterogeneous networks, capturing multiple weather effects for accurate power loss estimation.

Contribution

It presents a novel unified model that accounts for various atmospheric conditions and angles, improving upon traditional single-coefficient models.

Findings

Model predictions align within 1 dB of MODTRAN simulations.

Attenuation varies by several decibels across different weather scenarios.

The model enhances link-budget accuracy for VHetNets.

Abstract

Free-space optical (FSO) communication is emerging as a key backhaul technology for next-generation vertical heterogeneous networks (VHetNets), whose architecture spans satellites, high-altitude platform stations (HAPS), unmanned aerial vehicles (UAVs), and terrestrial nodes. Along these vertical and slant paths, optical beams traverse successive atmospheric layers that may contain clouds, fog, rain, and aerosols, conditions that conventional single-coefficient Beer-Lambert models typically handle only in isolation. Instead of such simplified formulas, we present a unified attenuation model that incorporates aerosols, fog, rain, cloud layers, and drizzle, accounts for the zenith angle, and provides a holistic estimate of the cumulative power loss across atmospheric layers. Numerical results show several-decibel attenuation variations across representative weather scenarios, while the difference between the proposed model predictions and the layer-resolved MODTRAN simulations remains within 1 dB, thereby validating the accuracy of the proposed model and its practical relevance for VHetNet link-budget studies.