Energy consumption in wired and wireless access networks

Energy consumption is becoming an increasingly important issue throughout the community. For network operators in particular it is a concern as networks expand to deliver increasing traffic levels to increasing numbers of customers. The majority of the energy used by the Internet today is consumed in the access network, and this will continue to be the case for the short-to-mid- term future. Access technologies should thus be a prime focus for energy use mitigation. In this article, we present a detailed analysis of energy consumption in current and future access networks. We present the energy consumption of DSL, HFC networks, passive optical networks, fiber to the node, point-to-point optical systems, UMTS (W-CDMA), and WiMAX. Optical access networks are the most energy efficient of the available access technologies.

Introduction

The Internet has revolutionized the way in which we seek and disseminate information, transact business, educate, and entertain. Traffic growth on the consumer Internet has been high and sustained, with growing numbers of Internet customers using increasingly sophisticated applications, and using them more often. The rollout of broadband access networks has both facilitated and been driven by these increasing demands. Service providers and network operators have invested heavily in deploying and upgrading these new access networks, investing as well in large data centers and expanding core network capacity. In general, these investment decisions have been driven by the traditional design metrics of capital cost, operational cost, and capacity requirements. Energy usage has always been considered, but in the context of operational cost rather than as an issue in its own right. In today's world, the traditional network design metrics alone are no longer sustainable, and energy needs to become one of the principal design parameters for future networks and equipment.