Integrated fault tolerance framework for wireless sensor networks

Safety critical applications, such as fire detection or burglar alarm systems, require continuous and reliable operation of Wireless sensor networks (WSNs). However, validating that a WSN system will function correctly at run time is a hard problem. This is due to the numerous faults one may encounter in the resource-constrained nature of sensor platforms together with the unreliability of the wireless links networks. A holistic fault tolerance approach that addresses all fault issues does not exist. Existing fault tolerance work most likely misses some potential causes of system failures. In this paper, we propose an integrated fault tolerance framework (IFTF) that provides a complete picture of the system health with possibility to zoom in on the fault reasons of abnormal phenomena. IFTF diagnoses network failures, detects application level failures, identifies affected areas of the network and may determine the root causes of application malfunctioning. These goals are achieved efficiently through combining a network diagnosis service (component/element level monitoring) with an application testing service (system level monitoring). Thanks to these two complementary services, the maintenance operations will be more efficient leading to a more dependable WSN. From the design view, IFTF offers to the application many tunable parameters that make it suitable for various application needs. Simulation results show that the presented solution is efficient both in terms of memory use and power consumption. IFTF incurs a 4 %, on average, increase in power consumption (communication overhead) compared to using solely network diagnosis solutions.