Comparison of Microwave Links Prediction Methods: Barnett-Vieants vs. ITU Models

摘要

Hydro-Quebec operates one of the widest electricity networks in the world. The microwave network infrastructure is essential to manage the power grid in Quebec and therefore, it is important to meet the reliability criteria that are generally above those accepted by traditional communication operators. In addition, over one third of the existing links has lengths between 70 km and 90 km and operates in extreme weather conditions and all year long. To address these constraints, the microwave links design needs to be as much accurate as possible. The aim of the research presented in this paper is to make a comparative study between two commonly used prediction models for microwave links: Barnett-Vigants and ITU-R P. 530. The first part of this work considers each of the following aspects (unavailability, diversity gain and conversion methods). We analyse each aspect as a function of frequency, fading margin and link length. The two models led to significantly different results for the unavailability due to multipath as a function of the link length, and also for the space diversity as a function of the gain difference between the main antenna and the diversity antenna. Remarkable differences between the two models were also observed when studying the unavailability due to rain as a function of the frequency. The second part of this work compares the overall performance of both models in terms of the total outage probability over ten links with different lengths and different locations. The differences observed for some links are significant.