Route Diversity Effect on 20 GHz Band Radio Relay Links

Rain outage performance on route diversity systems, necessary for the circuit design of millimeter communication systems, is examined by comparing it to that of a tandem system. The analysis is mainly based on the attenuation data measured over about two and a half years at the 20 GHz band on 13 tandem links near Tokyo. It is shown that the joint probability of rain attenuation on two paths can be expressed as a function of the path correlation coefficient on the two paths under consideration, and the evaluation of the rain outage performance can be approximated by the joint probability on pair hops of a diversity route. An estimation method using the path length enlargement effect is proposed for the estimation of the route diversity improvement.