Date Added: May 2012
In mobile technologies two trends are competing. On the one hand, the mobile access network requires optimisation in energy consumption. On the other hand, data volumes and required bit rates are rapidly increasing. The latter trend requires the deployment of more dense mobile access networks as the higher bit rates are available at shorter distance from the base station. In order to improve the energy efficiency, the introduction of sleep modes is required. The authors derive a heuristic which allows establishing a baseline of active base station fractions in order to be able to evaluate mobile access network designs. They demonstrate that sleep modes can lead to significant improvements in energy efficiency and act as an enabler for femtocell deployments.