Towards Green Copper Broadband Access Networks

This paper gives an overview on the state of the art of the different options to save energy in copper based broadband access nodes while maintaining performance and Quality of Service (QoS). The main focus is on the potential energy saving in the physical layer and the access network architecture. We show that today the physical layer when not optimized properly is one of the main sources of power consumption in copper based access networks. On the one hand this is due to the intrinsic high attenuation of the copper lines, and to the electromagnetic coupling between lines in the same cable on the other hand. Moreover, we show that the redesign of access network architecture and moving from a centralized network architecture to a more distributed network architecture also improves the energy efficiency. It can be shown that under reasonable assumptions between 39 to 200 GWh per year can be saved globally. 1