SON Use Case Study "Energy Saving" for LTE eNBs

The 3GPP is defining a next generation radio access network called LTE (Long Term Evolution), which introduces several improvements respect current mobile systems, one of them are self-organization and self-optimization functions (SON) in base stations (eNB) and O&M subsystem, that suppose a considerable increase on the network "intelligence". This paper discusses the application of a SON function, Energy Saving, and evaluates the energy savings and system performance, when applied. To illustrate the effect of the energy saving techniques, several simulations have been carried out with a radio-planning tool in a real mobile network deployment. Two technical approaches have been followed: switching off cells and reducing the eNB transmitted power (TXP). For both approaches a reference scenario with 18 eNBs (with 54 cells) has been selected. This scenario reflects a dense urban area with a Manhattan like distribution, in an area of 2 km x 2 km, with an average ISD of 250 m. A 2x2 MIMO antenna configuration has been used in all simulations. eNB's transmitted power was 46 dBm, the operation frequency was 2 GHz and the bandwidth was 5 MHz. The Energy Saving is a promising SON Use Case that allows decreasing operator's energy costs, carbon footprint, and the radiation emitted by fixed infrastructure of the mobile telephony systems, such as base stations antennas.