System Selection and Sleep Mode for Energy Saving in Cooperative 2G/3G Networks

In this paper, we focus on developing energy-efficient radio resource management (RRM) algorithms for heterogeneous networks. Our aim is to optimize energy consumption at the network scale, while preserving the quality of service (QoS) perceived by users. We develop a system selection algorithm that finds the optimal traffic allocation for the different systems that minimizes power consumption while insuring the target QoS. We apply our algorithm to a cooperative 2G/3G network and show that only a little gain can be obtained, as base stations still have a large energy consumption even if they have no traffic. We then propose a network scale "sleep mode" where an entire system (2G or 3G) can be desactivated for some traffic scenarios. We show that this mode, together with the energy-aware system selection, achieves large energy reductions.