Energy Efficiency in Wireless Networks : Impact of Adaptive Radio Unit Activation

Sammanfattning: Energy consumption in mobile networks, e.g. 3G networks, may be a substantial part of an operator's expenses. A large part of the total energy of the network is consumed by the radio access network. Radio Base Stations (RBSs) are the highest contributors to energy consumption and CO2 emissions in GSM and WCDMA mobile networks. While mobile network equipment is becoming more efficient, the increasing traffic demand and number of RBSs still increase the overall energy consumption of the networks. Putting the underutilized components of RBSs in sleep mode during low load can make the mobile networks more energy efficient. This study involves modeling the energy consumption of the macro base station components such as Radio Unit (RU), base band unit, cooling equipment, etc over different load scenarios. Based on the traffic load of each cell in the RBS, the number of active radio units needed for handling the traffic was selected and the rest of the radio units of the cell were put in sleep mode. A traffic scenario from a European city during 22 days is used to estimate the energy saving when using the above mentioned approach. Numeric results show that, for this traffic scenario an energy saving around 50% is achievable suggesting that there is a large potential for enhancing energy efficiency in mobile networks.