Repairing sensors strategies in fault-tolerant wireless sensor networks

Abstract

Fault-tolerance is one of the main issues in Wireless Sensor Networks (WSNs) where applications require a continuous service. In this paper, we show how to use a small number of mobile robots to handle failures that may occur in the WSN. We study two strategies: Centralized Manager Strategy (CMS) and CMS with anticipation noted by CMS* to detect, report sensor failures and coordinate the movement of robots. The goal is to minimize the dysfunction time and avoid the coverage and connectivity degradation of the network upon a failure. The CMS is based on the Centralized Manager Algorithm [1] that we improve to ensure that the central manager robot receives a report upon an occurred failure. This manager robot selects a maintainer robot to replace the failed sensor. However, in the CMS* we propose, the manager robot anticipates the sensor failure and reacts before it happens using an energy state model representing the behavior of a sensor based on a discrete time Markov chain.