Fade Slope Statistics on a Slant Path at 50 GHz

Abstract

Statistics of fade slope at 50 GHz have been derived from one year of slant path attenuation measurements, using time interval lengths between 2 and 200 s. From these statistics, the dependence of fade slope on the attenuation level and time interval can be quantified. It has been found that the ITU-R model, specified for frequencies up to 30 GHz, fits well the experimental conditional distributions. Nevertheless, some divergences are observed for the lowest attenuations, which may be attributed to cloud effects. Such results are required for the design of communications systems operating in the -band.

Rain fade slope model for terrestrial microwave links

“…The following observations are noted. First, all the fade slope distributions here are symmetric around 0 dB/s which confirm the finding of other researchers [14, 16–19, 21]. Second, all the CPDFs follow normal distribution with zero average.…”

“…Both found that the ITU-R model is well fitted to the measured data. The same result was obtained by Garcia-Del-Pino in Spain at 50 GHz [21]. In Finland, Salonen [22] compared the ITU-R model with the measured data from satellite link at a low elevation angle (12.7°).…”

“…Then, a new empirical model based on the data from the 23 GHz link is proposed in the section “Proposed model for fade slope prediction.” Finally in the last section, the model is validated using the data from the 15 and 38 GHz links. This validation is made possible since earlier studies in [9, 18, 21, 31] have shown that the fade slope distribution is independent of frequency.…”

“…The conditional distributions at the attenuation level A (in dB) is calculated based on all the attenuation values A ( t ) that satisfy the following inequality: where A = 1, 2, 3, 4,… dB. For example, the 1 dB distribution is obtained considering all the slopes calculated using (1) for an attenuation A ( t ) between 0.5 and 1.5 dB [21, 22]. The distribution characteristics and its behavior are discussed in the next section.…”

Analysis of rain fade slope for terrestrial links

“…where A= 1,2,3,4, … dB. For example, the 2 dB distribution is obtained considering all fade slopes calculated for attenuation A(t) between 1.5 and 2.5 dB [7,19]. Figure 1 shows the CPDF at selected attenuation levels of 1, 3, 5, 10 and 15 dB for the microwave links operating at 15, 23 and 38 GHz.…”