Green Communications: An Emerging Challenge for Mobile Broadband Communication Networks

Worldwide mobile broadband communications networks are increasingly contributing to global energy consumption. In this paper we tackle the important issue of enhancing the energy efficiency of cellular networks without compromising coverage and users perceived Quality of Service (QoS). The motivation is twofold. First, operators need to reduce their operational energy bill. Second, there is a request of environmental protection from governments and customers to reduce CO2 emissions due to information and communications technology. To this end, in this paper we first present the holistic system view design adopted in EARTH (Energy Aware Radio and neTworking tecHnologies) project. The goal is to ensure that any proposed solution to improve energy efficiency does not degrade the energy efficiency or performance on any other part of the system. Then, we focus on technical solutions related to resource allocation strategies designed for increasing diversity order, robustness and effectiveness of a wireless multi-user communication system. We investigate both standalone and heterogeneous cells deployment scenarios. In standalone cells deployment scenarios, the challenge is to reduce the overall downlink energy consumption while adapting the target of spectral efficiency to the actual load of the system and meeting the QoS. Then, with heterogeneous deployment scenarios, different cell scales that ranges from macro to