Network energy saving technologies for green wireless access networks

The energy consumption problem in the mobile industry has become crucial. For the sustainable growth of the mobile industry, energy efficiency (EE) of wireless systems has to be significantly improved. Plenty of efforts have been invested in achieving green wireless communications. This article provides an overview of network energy saving studies currently conducted in the 3GPP LTE standard body. The aim is to gain a better understanding of energy consumption and identify key EE research problems in wireless access networks. Classifying network energy saving technologies into the time, frequency, and spatial domains, the main solutions in each domain are described briefly. As presently the attention is mainly focused on solutions involving a single radio base station, we believe network solutions involving multiple networks/systems will be the most promising technologies toward green wireless access networks.

Introduction

The mobile industry faces a critical energy consumption challenge. Anticipated by Gartner [1], by 2013 smartphones will exceed 1.82 billion units and surpass PCs as the most common web access devices. Consequently, more wireless infrastructures have to be deployed with large demands on energy. Meanwhile, data-intensive services are beginning to dominate mobile ser-vices. The network data volume is expected to increase by a factor of 10 every five years, associated with a 16–20 percent increase of energy consumption [2]. Applying this rate to mobile communications, which contribute 15–20 percent of the entire information and communications technologies (ICT) energy footprint and 0.3–0.4 percent of global CO₂ emissions [2], the mobile industry faces a great sustainable development problem in energy consumption. It is crucial to develop energy-efficient wireless technologies to meet this challenge.