On the reliability of solar-powered point-to-point radio backhaul networks

As of today, broadband connectivity in developing countries, particularly in rural areas, has not been realized in a satisfactory manner. Coordinated point-to-point radio networks constitute a reliable and cost-efficient technology for wireless backhauling to remote regions. In mountainous regions like the Alps, such networks are deployed to provide Internet connectivity to remote villages. In Sub-Saharan countries such as Tanzania, they serve as an increasingly popular solution to connect sparsely populated areas. However, due to the remote location of radio nodes, no power grid for reliable energy supply is available. Rather, backhaul nodes are equipped with photovoltaic (PV) modules that charge buffer batteries that in turn supply energy to the network equipment. Without sufficiently dimensioned batteries and solar panels, radio nodes are prone to failure which in turn result in network outages and limited service availability. Hence, the deployed equipment for autarkic power supply has to accommodate for periods of lull or overcast skies. In this context, this paper derives recommendations and general rules on how to dimension power supply components to allow for reliable point-to-point wireless backhauling.