Active node based fault tolerance in Wireless Sensor Network

In this paper, we propose a novel idea of an active node model in Wireless Sensor Network (WSN) to identify the faulty nodes using battery power model and interference model. Fault tolerance against low battery power is designed through hand-off mechanism where in the faulty node selects the neighboring node having highest power and transfers all the services that are to be performed by the faulty node to the selected neighboring node. The hand-off mechanism involves transmitting the connectivity status of a faulty node such as source address, destination address, previous hop address, next hop address and time stamp to selected neighboring node. Fault tolerance against interference is provided by dynamic power level adjustment mechanism by allocating the time slot to all the neighboring nodes. If a particular node wishes to transmit the sensed data, it enters active status and transmits the packet with maximum power; otherwise it enters into sleep status having minimum power that is sufficient to receive hello messages and to maintain the connectivity. The performance evaluation is tested through simulation for packet delivery ratio and control overhead and we see that there is an improvement in the network throughput and reliability.