December 1, 2012

Energy-efficient Mobile Communication Networks

Potentials for Energy-Savings in Mobile Communication Networks

Commissioned by the Federal Ministry of Economics and Technology (BMWi), re­searchers at the Fraunhofer Heinrich Hertz Institute are now engaged in the Commu­ni­cate Green project on optimizing the energy efficiency of mobile communication networks in Germany. The overall aim of the project is to adapt the transmission capacity now supplied to real demand. This would mean that up to two million tons of CO2 a year could be saved in Germany without any loss of quality in the telephone connection.

No Need for Over-Capacity

Mobile communication networks enable telephony and the transmission of data with mobile phones. Each network is subdivided into radio cells whose size and number depends on the number of users and the data rate. Each radio cell has sender and receiver stations known as "base stations". Higher numbers of users and higher data rates mean a larger number of base stations. It is estimated that base stations account for 80 percent of energy consumption in mobile communication networks. Overlapping of radio cells results in excess supply and thus higher energy consumption.

Optimized Mobile Communication Networks

Mobile communication networks in Germany are not fully used at all times of day and in every location. In the Communicate Green project scientists at HHI are investigat­ing opportunities to tailor transmission capacity to real user demand, and thus to lower energy consumption. Savings in CO2 can be achieved through:

  • Targeted sleep modes for radio cells when not in use,
  • Reducing the transmission capacity of base stations in periods of limited use, and
  • Switch-off of single hardware elements in the base station.

Optimization of wireless networks enables energy savings by ensuring that users everywhere are given the transmission capacity they actually need instead of the maximum capacity as has been the case so far.