Energy saving is important for operators' operational efficiency. Energy consumption is a significant operational cost
factor, for example in developing markets, up to 30% of OPEX is spent on energy. For one operator group, almost 80%
of base stations in Africa and India use diesel as the primary or as a backup power source. Furthermore, base stations
account up to 80% of the total CO2 emissions in a mobile operator network. Many operators have a target to cut CO2
emissions as part of their environmental objectives. With increasing voice usage, data usage (e.g. introduction of smart
phones, MTC devices, etc.) and more dense networks, the thirst for energy consumption is expected to increase further,
hence, motivating the need for low energy base station technology. Increasing the energy efficiency of base stations or
reducing the energy consumption of base stations will also facilitate the possibility for operators to power all types of
base stations with alternative fuels and rely less on fossil fuels either from diesel generators or from the electricity grid.
The present document provides a study into BTS energy saving solutions. The present document analyses and evaluates
different solutions to determine the benefits provided compared to the legacy BTS energy consumption.
In the scope of this study there are following solutions:
Reduction of Power on the BCCH carrier (potentially enabling dynamic adjustment of BCCH power)
Reduction of power on DL common control channels
Reduction of power on DL channels in dedicated mode, DTM and packet transfer mode
Deactivation of cells (e.g. Cell Power Down and Cell DTX like concepts as discussed in RAN )
Deactivation of other RATs in areas with multi-RAT deployments, for example, where the mobile station could
assist the network to suspend/minimize specific in-use RATs at specific times of day
And any other radio interface impacted power reduction solutions
The solutions will also consider the following aspects:
Impacts on the time for legacy and new mobile stations to gain access to service from the BTS
Impacts on legacy and new mobile stations to keep the ongoing service (without increasing drop rate)
Impacts on legacy and new mobile stations implementation and power consumption, e.g. due to reduction in DL
power, cell (re-)selection performance, handover performance, etc.
Impacts on UL/DL coverage balance, especially to CS voice
Solutions will be considered for both BTS energy saving non-supporting and supporting mobile stations (i.e. solutions
that are non-backwards compatible towards legacy mobile stations will be out of the scope of this study).
The contents of the present document when stable will determine the modifications to existing GERAN specifications.