Outage Probability versus Carrier Frequency in GeoSurf Satellite Constellations with Radio-Links Faded by Rain

Abstract

For sites located in different climatic regions, we estimated the relationship between the annual average probability distributionof exceeding a fixed rain attenuation, and the carrier frequency in the range 16 to 100 GHz, in the zenith paths of GeoSurf satellite constellations. In these constellations rain attenuation is independent of the altitude and number of satellites. Rain attenuation iss calculated with the Synthetic Storm Technique, a reliable prediction method, by using on-site measured rain-rate time series. A suitably defined outage probability factor shows that the outage probability, for fixed power margin, tends to saturate as frequency increases. In wideband radio-links, such as in spread spectrum design, there is very likely a long-term distortion due to the in-band outage probability. The results are oriented to design systems faded by rain attenuation whose value is also the total power margin available due to a mixture of coding and hardware technology, whose combination is not of concern here.

Transfer Functions and Linear Distortions in Ultra-Wideband Channels Faded by Rain in GeoSurf Satellite Constellations

“…Now, because the relationship between 𝐴(𝑡) or Φ(𝑡) and 𝑅(𝑡) is monotonic, the onsite probability distribution 𝑃(𝑅) is transformed directly into the 𝑃(𝐴), 𝑃(Φ) of the zenith path through the variable transform given by Equation (9). Figure 4 of [3] shows the annual average probability distribution 𝑃(𝐴) for the sites listed in Table 1. Figure 3 shows the annual probability distribution 𝑃(𝑅).…”

“…For illustrating the general characteristics of linear distortions in very large bandwidths, we report the results concerning the sites listed in Table 1, located in different climatic regions, already studied in [3]. We have considered these specific sites because of the availability of rain-rate time series 𝑅(𝑡) (mm/h), with rain rate averaged in 1-min intervals, continuously recorded on-site for several years.…”

A Small Power Margin and Bandwidth Expansion Allow Data Transmission During Rainfall Despite Large Attenuation: Application to GeoSurf Satellite Constellations at mm–Waves

“…In designing satellite links above 10 GHz -frequency beyond which the attenuation due to rainfall is no longer neglible -the traditional approach is to consider the average (annual or worst month) probability distribution 𝑃(𝐴) of exceeding rain attenuation 𝐴 (dB) [1][2][3][4][5][6][7][8][9]. In the design, 𝑃(𝐴) is considered the outage probability and 𝐴 (dB) the required power margin necessary to maintain the link working, i.e.…”

“…No measurements or predictions are, however, available for zenith paths, therefore we consider as experimental results the rain attenuation time series 𝐴(𝑡) simulated in zenith paths with the Synthetic Storm Technique (SST) (see Equation ( 29) of [21], or [3]) from rain-rate time series 𝑅(𝑡), recorded on-site for several years in the sites listed in Table 1. The SST is a powerful tool [2-5; 22-28].…”

“…Moreover, these particular sites are important study-cases because satellite ground stations of NASA and ESA are located there (Fucino, Madrid, White Sands), or because longterm radio propagation experiments were performed at the sites (Fucino, Gera Lario, Madrid, Spino d'Adda), or just because there are large cities (Prague, Norman, Tampa, Vancouver). Following our previous studies of the GeoSurf links [2][3][4][5]28], we simulate 𝐴(𝑡) at 80 GHz (mm-wave), circular polarization.…”