Ad-hoc multilevel wireless sensor networks for distributed microclimatic diffused monitoring in precision agriculture

The paper presents an innovative solution for the realization of wireless sensor networks suitable to characterize the microclimatic behavior in agriculture fields. The nodes are equipped with sensing units to measure several physical parameters. They are designed in order to minimize power consumption, being able to work for a whole season without any energy harvester. The network is implemented at two levels. Data from distributed sensing units are initially collected via a single-hop connection and then forwarded to the Internet gateway via a multi-hop transmission scheme. The two levels use interchangeable ISM frequencies, thanks to the design of dual band loop antennas. In this way, flexibility and scalability can be easily reached. The trial that is currently tested in Montepulciano, Italy, has initially evidences problems originated by package permeability to humidity and water. Once the issue has been solved, reliability has reached 99%.