Energy efficient radio resource management for green cellular networks

The need of a sustainable economy is driving also communications to be able to provide their services with a low carbon footprint. Focusing on mobile communications, it is expected that the increasing of subscriptions during next year will lead to a growth of energy consumption due to the infrastructure capacity improvement if no action is taken. Therefore researchers and mobile operators are now looking for innovative solution able to cope with this network evolution. The control and the reduction of energy consumption in mobile communications will have two main benefic eeffects. First of all environment will benet because of the concentration decreasing of greenhouses gases that are responsible of the global warming. Then, since energetic bill is one of the main expenditure items of a mobile operator, the introduction of energy saving solution will allow the operators to reduce their operational costs in managing the network. This thesis deals with the radio resource management strategies to reduce the cellular network energy consumption. A forecasting driven solution is introduced to decide how many resources, i.e. active base stations or carriers on air, and their transmission power are enough to satisfy the hourly requested capacity. The use of forecast is justfied by the behaviour of cellular trac and allows to match the daily power figure to the traffic pattern, avoiding the waste due to the overprovisioning. Moreover an optimization framework is introduced to find the optimum network configuration able to minimize the global power consumption for a given number of simultaneous active users. This framework plays with the number of active base stations, the association between users and base stations, the bandwidth allocated to each user and the transmission power at each antenna tower. Finally the focus is moved to private mobile radio and to TETRA system. A TETRA power consumption model is provided and some solutions to reduce the carbon footprint of today ~Os TETRA system are evaluated. Moreover some considerations about the future evolution to a TETRA over LTE system are given taking into account also the energy saving potentials of LTE systems.