Shadowed Rician model is considered to be the most appropriate that is used to characterize the impairments seen in wireless channels, which suffer Line-Of-Sight (LOS) shadowing and small-scale fading. In this model, the Probability Density Function (PDF) of the Signal to Noise Ratio (SNR) per symbol needs numerical solutions to be evaluated. More than that, for some values of the fading parameters, the numerical solution converging too slowly, and so needs too much time to be evaluated. This is considered as a problem in real time applications where delay is a critical issue. In this paper, the authors present and prove approximations for Shadowed Rician model according to the values of the fading parameters, which are the Rice factor and the Shadowing standard deviation. With the proposed approximation, the required PDF could be written in intervals which make it easier to calculate at parameters values that causes slow converging.

Unmanned Aerial Vehicle "UAV" networks are rapidly evolving towards real world effective applications. Major research arenas are being motivated by industry activities in this domain, which demand for rapid exploitation of tremendous advantages of UAV networks. Routing is one of the most important functionalities in such networks. Based on channel characteristics, several factors play important roles in defining the best route for each node with its neighbors, which shall be set dynamically in real time. In this paper, we propose a computation of the required cost function for building the routing table; this cost function is strongly related to the transmission quality factor of the channel. We show the simplicity of our proposed method compared to Bit Error Rate "BER" calculation, together with an evaluation and assessment using simulation. 