Utilizing eNodeB sleep mode to improve the energy-efficiency of dense LTE networks

This study evaluates the performance of a scheme, where idle capacity cells are put into sleep mode to save energy. The evaluation is performed for a few different LTE network densification alternatives, and the network performance is compared from the daily energy consumption point of view. The obtained results indicate that the introduction of the sleep mode scheme results in 42-62% lower daily energy consumption, depending on the network densification alternative. Furthermore, the evaluated heterogeneous network deployments are found to be more energy-efficient than the densified macro deployment, which is a clear difference compared to scenarios without any energy saving schemes. If the sleep mode deployment is compared to a scheme, where underutilized capacity cells are completely switched off, the gain becomes equal to 26-43%. The results demonstrate also that the network energy consumption can be further reduced with the help of fast cell DTX. For example, if a fast cell DTX scheme reducing the idle state power consumption by 50% is assumed, the daily energy consumption becomes 31-37% lower than without fast cell DTX. Finally, the combination of fast cell DTX and sleep mode deployment results in 63-75% lower daily energy consumption compared to scenarios without any special energy saving schemes.