Analysis of the statistical distribution of accumulated thermal noise in a multilink microwave system

Increased utilisation of the bands below 10 GHz and requirements for high-speed digital data transmission have necessitated the use of higher frequencies for the terrestrial line-of-sight communication links. In this frequency range signal attenuation is caused by rain. The outage time probability and the accumulated thermal noise can be considered to be the crucial parameters for the appropriate design of the whole communication system including the repeaters. The subject of the paper is the development of a theoretical model for the prediction of the accumulated thermal noise. Numerical results are compared with data taken from a transmission system in the 20 GHz band located in Japan.