Reducing energy consumption in mobile cellular networks is a significant goal. It would therefore be desirable to switch off the Power Amplifier (PA) of a Base Station in the network, when it is not required. The PA consumes a significant amount of energy.
Existing ideas for switching off a PA in a Base Station relate to situations where more than one PA is used on the same sector. Switching off one PA when there is no need for the additional data traffic capacity is useful. However, even when there are no users requiring any data traffic, the Base Station continues to provide a full downlink service in that sector, which still leads to unnecessary energy consumption.
Self-Optimised Networks have been suggested. In this context, flexible network planning might be considered, whereby cells can modify their transmission power, for example to cover coverage holes.
There are a number of existing options for dynamically extending cell coverage. Smart antennas have been developed that can dynamically modify the coverage of a cell, for example, by changing the antenna radiation pattern and using the increased antenna gain in a certain direction and additional power available to extend the cell range. Also, the use of a multi-carrier PA in the Base Station provides that there may be excess power not being used in a particular sector, and this power could be used on one carrier to extend coverage.
Even with these existing technologies, matching the energy consumption to the required data traffic throughput remains a challenge in network planning.