Influence of climate variability on performance of wireless microwave links

Microwave telecommunications links that are operating above 10 GHz are significantly affected by precipitation, especially by rain. In order to study the attenuation caused by precipitation a measurement system is operating at BME-HVT. The results of the measurement system can also help to examine the change of the climate, whereas variations in the intensity and frequency of precipitation indicate variations in the characteristics of the propagation of microwaves as well. A nonconstant climate indicates necessary changes in the network planning of microwave telecommunication networks in order to adapt the link performance (i.e. availability, fade margin, etc.) to the forthcoming climate conditions. Moreover, whereas the climate can vary in time and space as well, it is important to have the local trends of the variation available. Our objective is to study the effects of the climate variability and climate change on the availability of the microwave networks by processing the attenuation measurement data of microwave links recorded during the last 14 years within local (Hungarian) conditions. In this paper results of four microwave links established in Budapest are investigated. In order to get a joint statistics of diverse links a transformation was performed on the attenuation data measured on the investigated microwave links. Thereby a local trend in the attenuation and fade duration statistics became available to be investigated, which is specific to Budapest. The results can help to improve the recommendations on microwave network planning and adapt them to the varying climate.