Page 65 - ITU Journal: Volume 2, No. 1 - Special issue - Propagation modelling for advanced future radio systems - Challenges for a congested radio spectrum

ITU Journal: ICT Discoveries, Vol. 2(1), December 2019

average annual over the observation period of two
years. A very significant observation not yet
mentioned anywhere in the literature is that for an
annual availability of (100-0.01)%=99.99% the
required fade margin using site diversity, despite
the different radio propagation characteristics in
England and Greece, for both countries is very
similar and around 2.8 dB as shown in Figures 5, 6
and 7. This suggests that the diversity gain in Greece
is much higher since the corresponding single link
excess attenuation experienced at 0.01% of the time
is also much greater than in the UK.

Fig. 5 - Average annual complementary cumulative
distribution of excess attenuation in Greece in comparison
with the ITU-R predictions

Fig. 3 - Average annual complementary cumulative
distribution of excess attenuation in Greece
in comparison with the ITU-R P.618-13 predictions

Fig. 6 - Average annual complementary cumulative
distribution of excess attenuation in the UK
in comparison with the ITU-R predictions

The independent joint attenuation cumulative
attenuation statistics [12], i.e. the product of the
single attenuation statistics, clearly shows that even
for site separations of 36.5 km and 48 km, as is the
case for the campaigns in Greece and the UK
respectively, there is a significant dependence
between the propagation effects at the two sites
(Chilton-Chilbolton and Athens-Lavrion).

Fig. 4 - Average annual complementary cumulative
distribution of excess attenuation in the UK
in comparison with the ITU-R P.618-13 predictions

© International Telecommunication Union, 2019 49