Effects of single vegetation obstruction on 5G mobile services in 28GHz

Vegetative medium causes the attenuation of radio frequency waves, whereby the attenuation increases with frequency. Fifth Generation bands will operate in very high frequencies, thus creating an emphasis to study the vegetative propagation properties of these signals. Different species of trees can cause a variation in propagation loss due to the difference of the tree crown shapes. Existing vegetation loss modelling does not take into account the effects of tree crown shape. Therefore, prediction result does not reflect the accurate amount of signal attenuation experienced by trees. An underestimation of the signal attenuation can cause bad link budget designing. This paper shows that the peak attenuation for hemispherical and spherical crown of common tree species found in Kuala Lumpur, Malaysia is 7.59 % and 3.83% different from the predicted signal attenuation with a fixed vegetation volume of 27m
³
. This paper suggests that existing vegetation modelling requires some adjustment before it can be applied for the assumption of vegetation attenuation when designing an RF link in very high frequency bands, especially in equatorial climates.