Link Failure Detection in Wireless Sensor Networks Using Watchdog

Abstract

A wireless sensor network (WSN) is defined as a collection of tiny sensor nodes connected via wireless links. This kind of network is deployed in harsh conditions to monitor a particular phenomenon. Each of the sensor nodes has three tasks; gathering the data, processing the data, and transmitting the data back to the sink node. Since the positions of these sensor nodes are not fixed, the network is capable of organizing itself, without any external intervention. One of the main features of WSNs is cooperation between the nodes, where all the sensor nodes cooperate each other to transmit the gathered information about a particular phenomenon. The performance of WSNs is restricted by the quality of wireless links. Link failures badly affect the network reliability, availability, and overall performance. In WSNs, due to a link failure, the shortest path from the current node to the sink node might be lost, which will force the data to be traversed by the longer path. This will result in increased energy consumption and longer transmission delays.
An energy efficient protocol is proposed here to provide a complete fault diagnosis of wireless sensor networks including the sensor node failures. The protocol has two phases, in the first phase it uses Watchdog mechanism to detect the misbehaving nodes, In the second phase the misbehaving nodes are diagnosed to check whether actually the nodes are faulty or the links. We implement both of the phases in ns2 simulator where we verify the efficiency of our protocol.