Wireless Sensor Networks (WSN) have been identified as one of the most promising technologies for various technology analysts and magazines, because they satisfy the current requirements concerning the establishment of networks that cover communication needs in a flexible (in space and time), autonomous (self-configuration), and being independent of a fixed structure. The ability to deploy low-cost devices with high operation time without the need of maintenance, which are able to obtain environment information and transmit it wirelessly to a coordination center offers unimaginable possibilities in many applications. 
In most applications it is intended that the nodes do not require maintenance, exploiting the concept of throwaway nodes, because once deployed they are not recoverable. In this environment, major challenges are to minimize two main factors: cost and consumption, maximizing the time of service.
In recent years many protocols have been proposed for WSN. However, most of these proposals, or make unrealistic assumptions or are not very scalable, which translates into non-practical approaches.
Furthermore, desirable characteristics, such as fault tolerance, safety and marking of time in communication, have generally been ignored, so they are not considered in the most of existing protocols, and when they are, the sacrifice of energy efficiency is required to be implemented. 
In this thesis an innovative solution is proposed, aimed primarily at reducing energy consumption. The new architecture called EDETA (Energy-efficient aDaptative hiErarchical and robusT Architecture) is also scalable, suitable for both homogeneous WSN’s and heterogeneous ones (increasingly employed), able to self-configure, which supports multiple sinks in a transparent manner, and provides features such as fault tolerance and bounded time responses, without degradation of the network performance.
The proposed architecture is based on a two-level hierarchy. The lower level is based on clusters, governed by an internal protocol called Intra-Cluster Communication, while the upper level consists of a dynamic tree node of cluster leaders, the so called Inter-Cluster Routing protocol.
The evaluation of the mechanisms has been performed through two ways: implementation and simulation, showing that the proposed mechanisms significantly increases the lifetime of the network, while providing additional robust communications, fault tolerance and time bounded response. This architecture has been successfully applied to real systems in different application fields.