ETSI TR 145 926 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 [4])
• 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.