System reliability of fault-tolerant Wireless Sensor Network for precision agriculture

Wireless Sensor Networks (WSNs) are smart devices that are used to monitor multiple physical parameters of a complex system, plant, or process. Most of the time, WSNs need to be installed in harsh outdoor environments, impacting their overall reliability and availability. This paper investigates the influence of redundancy and fault tolerant architecture on the reliability of a WSN used in precision agriculture. Specifically, it investigates the design and deployment of a low-cost, self-powered WSN, assessing its reliability considering the real environmental conditions in which the systems need to operate, as well as taking into account the actual node placements in the field. The reliability of all the different wireless node and general subsystems has been studied using reliability prediction handbooks, and then combined by means of dedicated Reliability Block Diagrams. Furthermore, the estimation of the battery End-Of-Life based on a large degradation dataset has been considered and merged inside the reliability analysis in order to improve the accuracy of the system's reliability.