Optimisation of Radio Techniques and Deployments for Energy Efficient Networks. (Optimisation des techniques et déploiements radio pour les réseaux efficaces en énergie)

The objective of this thesis document is to contribute into the set of techniques for energy efficiency in mobile networks, the often so-called Green Radio mechanisms. The work has been done taking as reference framework the current and future trends in mobile and cellular technologies as 3G/W-CDMA, LTE and LTE-Advanced. This has permitted us to classify these methods in a coherent classification framework, as well as establishing the different advantages, drawbacks of each one these techniques and also have an idea of how those approaches could work together by means of integration. Into the set of techniques, we have different mechanisms that work at different scales and abstraction levels: the Base Station (BS) component enhancement approach, the Cognitive Radio (CR), the transmission link level improvements, the Radio Resource Management (RRM) optimisation and at the top level we have the cell layout adaptation mechanisms where we find the heterogeneous network approaches, as well as the switching-off & cell breathing mechanisms. We decide in this thesis, after the previous studies done on the green radio techniques, to contribute specifically on this already discussed top-layer given the important global network savings that could be obtained from this level. First, we start by concentrating our efforts on the Radio Access Network (RAN) energy consumption problem. In order to have an energy efficient network, we propose a BS distributed and clustered cell-breathing technique that provides a self-organized BS switching-off and network adaptation mechanism that avoids the use of a centralised server and their associated single-point failure issues. Then, we try then to take into account in such an approach, the Mobile Station (MS) side and its individual transmitting power. Due to the increase of cell sizes as consequence of cell breathing, the uplink transmitted power noticeably increases with undesirable consequences as an associated electromagnetic radiation increase and a reduced battery lifetime. Here, we propose means to regulate the cell-breathing behaviour in order to find a trade-off between MS transmission power vs. RAN power consumption. Afterwards, we enhance the already discussed proposal done in cell-breathing by combining it with a heterogeneous network approach, specifically a Macro/femto-layer network. The proposed approach increases the capabilities of BS switching-off at the Macro-layer by including also the possibility of having a macro-to-femto offloading. In the studied scenario, the potential issue of access blocking due to Closed Subscriber Group (3GPP CSG)[1] access polices is taken into account. Also at this level we study other issues as the mechanisms to handle coverage holes as consequence of relying on