László Hévizi

Enablers for Energy Efficient Wireless Networks

Mobile communications are increasingly contributing to global energy consumption. The EARTH (Energy Aware Radio and neTworking tecHnologies) project tackles the important issue of reducing CO2 emissions by enhancing the energy efficiency of cellular mobile networks. EARTH is a holistic approach to develop a new generation of energy efficient products, components, deployment strategies and energy-aware network management solutions. In this paper the holistic EARTH approach to energy efficient mobile communication systems is introduced. Performance metrics are studied so to assess the theoretical bounds of energy efficiency and the practical achievable limits. Moreover, various deployment strategies focusing on their potential to reduce energy consumption are studied, whilst providing uncompromised coverage and user experience. This includes heterogeneous networks with a sophisticated mix of different cell sizes, which may be further enhanced by energy efficient relaying and base station cooperation technologies. Finally, scenarios leveraging the capability of advanced terminals to operate on multiple radio access technologies (RAT) are discussed with respect to their energy savings potential.

Power savings in mobile networks by dynamic base station sectorization

The authors conclude that instantaneous cell-load and buffer service-rate measurements can serve as input to various energy saving network algorithms. For example, such algorithms can control intelligent sleep modes in a mobile network, and can turn on and off radio resources according to the temporal and spatial variations of traffic. In particular, the authors demonstrate that underutilized 3-sector base stations can be reconfigured to omnicell base stations without significant service degradation in a network and that can save the power of two out of three radio units on typical 3-sector base stations.

The effect of F-DPCH on VoIP over HSDPA Capacity

In WCDMA Rel. 5 HSDPA the fraction of the base station power used for signalling channel overhead is relatively large for low bit-rate services such as VoIP. Examples of such overhead are the high speed shared control channel (HS-SCCH) and the associated dedicated channel (A-DPCH). One remedy is the suggestion of using a fractional dedicated channel (F-DPCH) instead of A-DPCH. In this paper we investigate the impact of power overhead for a system with only VoIP users. The capacity is compared both theoretically and through dynamic radio network simulations. Theoretical and simulated results both show a capacity increase of around 15% when A-DPCH is exchanged by F-DPCH