At the network level, the potential for reducing energy consumption lies in the layout of networks and their management. Network management needs to take slowly changing daily load patterns into account, as well as highly dynamic traffic fluctuations. Moreover, research has to analyze new architectures with more disruptive approaches, including multi-hop transmission, ad-hoc meshed networks, terminal-to-terminal communications and cooperative multipoint architectures. The use of cellular heterogeneous structures, and cooperative transmission from several base stations to one mobile device, are further enablers.