B4-Attenuation and Scattering

⌘ Interaction of electromagnetic waves with the Environment
Examples are:
 * leaves will mainly interact around 6 Unik/GHz: thickness will attenuate, whereas reflection is due to diameter of leaves
 * branches will have main interaction at about 1 Unik/GHz
 * the tree trunk will interact with almost all frequencies at 30 Unik/MHz and above.

⌘Attenuation parameters for 2.4 GHz
Measurements performed for European building

(Source:Hydra Deliverable D5.4, p 12)

⌘ Path loss calculation
Hydra pass loss approximation $$ L = 92,4 + 20 \log(d \mathrm{[km]}) + 20 \log(f \mathrm{[GHz]}) + \sum{n_i \alpha_i}$$


 * relation between fading margin and receiver sensitivity