Long Term Irradiance Statistics for Optical Geo Downlinks: Validation With Artemis Experimental Measurements

Abstract

In this Letter, a methodology for the generation of received irradiance/power time series for a GEO downlink concentrated on small aperture receiver terminals is reported. The synthesizer takes into account the atmospheric phenomena that degrade the propagation of the optical signal and especially the turbulence effects. For modeling the scintillation effects, Kolmogorov spectrum is assumed, and the Rytov's approximation under weak turbulence is also used. The time series are generated using the theory of stochastic differential equations. Finally, the proposed synthesizer is compared in terms of first order statistics with experimental data from the ARTEMIS GEO optical satellite link campaign with very good agreement.

Time Series Irradiance Synthesizer for Optical GEO Satellite Downlinks in 5G Networks

“…The analysis begins examining the case where no turbulence is present and the optical signal, a single collimated Gaussian beam, is only affected by free-space diffraction. Therefore, for a free space optical GEO downlink communication system the received irradiance can be given according to the formula [6,11,15]:…”

“…where P T (Watts) is the transmitted power, η T , η R are the efficiencies of transmitter and receiver respectively, η atm is the atmospheric transmittance, L(m) is the link distance (slant path), r is the radial distance from the beam center and W(L)(m) is the beam waist after propagation of distance L given according to the next formula [6,11,15]:…”

“…In log-log scale the latter function is a straight line with −8/3 slope and verifies that the spectra of downlink scintillation decreases with −80/3 dB/decade. optical GEO downlink communication system the received irradiance can be given according to the formula [6,11,15] is the beam waist after propagation of distance L given according to the next formula [6,11,15]:…”

“…In 13 In the presence of clear air turbulence, the signal propagation suffers from scintillation effects and beam effects, that is, beam wandering and beam spreading. However, in downlink only the scintillation effects are most significant, and based on the assumptions about Rytov theory and the Kolmogorov spatial spectrum, the received irradiance time series are given by the next expression [6,11,15]:…”

“…The synthesizer is validated in terms of first and second order statistics with experimental results from the ARTEMIS optical link campaign and afterwards derived numerical results are reported [13,14]. In a previous paper [15], a preliminary version of the proposed generator has been presented and only the first order statistics have been validated. In this contribution, an extensive validation of the synthesizer using both first and second order statistics results is performed and its usage for system-level simulation and for fading techniques modeling is highlighted.…”