Study on Tropospheric Scatter Beyond-line-of-sight Channel Transmission Loss for Short-term and Long-term Fading

Tropospheric scatter (Troposcatter) communication is an important means for ground microwave beyond-line-of-sight propagation. Available troposcatter transmission loss models are inefficient to describe the random variables resulting from atmosphere environment and other factors. Therefore, this paper studies the short-term fading and long-term fading characteristics of transmission loss based on those of electric field strength for the first time. The distribution model of transmission loss is modeled, whose parameters are estimated referring to ITU-R P.617-3. Parts of measured scatter links data from International Telecommunication Union (ITU) are chosen to verify this model with normal distribution graph. The result shows that the long-term fading of transmission obeys the normal distribution. It gives the basis of calculating error bit for the further work. In addition, a transmission loss prediction method is proposed based on its distribution model. It is verified to have a good accuracy using measured data, and this method address the problem that available transmission loss methods can not predict the values at any time percentages.