Additionally, we evaluate the two-tier coexistence scenarios considering a practical radio channel propagation model which includes path loss attenuation, shadowing and multi-path fading.
This situation becomes even worse when STs are within the I R PT, due to the complexity of the wireless transmission environment (e.g., channel fading, shadowing, and signal attenuation) [17].
The propagation matrix models independent fast fading, geometric attenuation, and shadow fading.
The parameter g k models the geometric attenuation and shadow fading, which is assumed to be independent over transmit antenna and to be constant over many coherence time intervals.
"Ballistic" photons are assumed to follow a straight path linking the x-ray source and detector pixel and form the basis of the attenuation based shadow graph imaging method that is used in essentially all routine x-ray imaging methods since its initial development by Roentgen and subsequent application to medical computed tomographic imaging by Hounsfield.
It is assumed that due to severe attenuation and/or shadowing effects, communication links can be established only with the aid of a relay node.
The direct link between each transmitter-receiver pair is assumed to be broken due to strong attenuation and/or shadowing effects.
However, the most significant challenge of the RSS readings is about the irregular variations of RSS due to the variable radio channel attenuation, signal shadowing, multi-path interference, and even the variations of indoor temperature [4].
where A s represents the maximal shadowing attenuation in dB, T s is the shadowing duration in seconds, t0 is the shadowing instance, and u is a model constant.
TAM describes the attenuation relationship between shadows and their non-shadow backgrounds in the three color channels, and this relationship can be used for shadow detection.
