Mobile backhaul in heterogeneous network deployments: Technology options and power consumption

Mobile communication networks account for 0.5% of the global energy consumption, a value that is expected to double within the next five years. For this reason, means of reducing the energy consumption in cellular mobile radio networks has recently gained great interest within the research community. In mobile networks the backhaul contribution to the total power consumption is usually neglected because of its limited impact compared to that of the radio base stations. However, meeting the almost exponential increase in mobile data traffic requires a large number of (mainly small) base stations. This means that backhaul networks will take a significant share of the cost and the energy consumption in future systems. Their actual contribution to the energy consumption will depend on the radio base station deployment scenario as well as on the technology and topology choices for the backhaul itself. This paper presents an initial assessment of the power consumption of two established backhaul technologies, i.e., fiber and microwave. For the microwave case, three backhaul topologies are considered, i.e., tree, ring and star, while for the fiber case only one topology is analysed, i.e., a dedicated point-to-point star. The presented results, assuming off-the-shelf products and based on todays network capacity levels, confirm the importance of considering the backhaul when minimizing the total power consumption in heterogeneous network scenarios. They also show the impact of the basic technology and topology choices of the backhaul for minimizing total power consumption.