Energy and cost efficient radio access network deployments — Case Finland

Energy consumption of radio access networks is strongly related to the speed and volume of mobile broadband traffic. Finland aims to achieve two conflicting targets by 2015, the one of 100 Mbps user data rate provision to nearly all citizens and the other of the reduction of Information and Communications Technology industry carbon footprint. The purpose of this paper is to evaluate the energy consumption and the deployment cost per mobile broadband subscription for several radio access networks deployment scenarios. Mobile operators can advance energy efficiency through (1) energy optimization of individual sites and (2) choice of energy efficient network deployment strategies. We model the power consumption on the site and network level, the mobile data traffic evolution, the average site traffic load factor, the demand-supply mismatch and the deployment cost per subscription. Then, we examine if the wide area access network evolution will be sufficient to meet the traffic demand in an energy and cost efficient way and whether the wide-to-local area offloading will happen. The results show reduction of annual energy consumption, assumed that only new sites are installed in mobile networks. However, only the scenario with fewer cellular sites operating at a lower frequency band and the scenario, in which the wide area network serves only outdoor subscriptions, keep the cost per subscription low. The last scenario enables the wide-to-local area offloading which is likely to happen in urban areas.