Energy-aware wireless-wired communications in sensor networks

In recent years many efforts have been spent on sensor networks, with a particular attention to routing, energy management, hierarchical data processing and aggregation aspects. What not generally considered is that the wireless unit can be intended as the data management node of a wired sub-network with sensorial units connected through a fieldbus. The outcome is a hybrid wireless-wired topology which shows several advantages over a simpler WSN: units connected to the bus can be powered through a common power supply unit; availability of a higher local bandwidth; accurate clock synchronization among units; energy savings at the local communication level (no wireless routing). In such a scenario, we propose a methodology to develop energy-aware fault tolerant wired communications in the context of a hybrid wireless sensor network. Nodes connected to the bus transmit sensed data to the wireless unit either through synchronous queries or in response to events, otherwise switching off themselves into a power-aware modality.