Fault Tolerance in Sensor Networks

The probability of failure of sensor nodes in sensor networks can be very high in some applications. So it very necessary to design the sensor networks such that, the failure of sensor nodes do not affect the proper functioning of network. Much importance has been given to make sensor network fault tolerant and reliable.

In a paper called “Fault tolerant clustering of WSN” fault tolerance of WSN is increased using detection of failed gateways, and re associating the senor nodes attached to the failed gateway with another existing gateway. Periodic checking for failure of gateways is done. If a failure is found, all sensor nodes attached to the failed gateway are reattached to a new gateway. This method prevents re election of the gateway, and increases reliability of wireless sensor networks.

In “Prolonging Sensor Network Lifetime with Energy Provisioning and Relay Node Placement” authors propose to provide extra energy to the AFN (Aggregating and Forwarding Node) similar to gateway. As a result of providing extra energy, failure of gateways can be prevented hence sensor network become more fault tolerant. The approach also proposes to use extra relay nodes after AFN and provide extra energy to the relay nodes also. The SPINDS algorithm proposed in this paper tries to solve the joint problem of relay node placement and energy provisioning.

In another approach called “WSN with Guaranteed Capacity and Fault Tolerance” authors propose deployment of extra nodes form a robot helicopter. These extra nodes are deployed to make wireless sensor network fault tolerant. All the nodes will not be awake simultaneously. Redundant nodes will be sleeping and wake up only when an active node dies.

In a patent called “Fault Tolerance in WSN” authors try to make WSN fault tolerant by the usage of secondary and tertiary gateways along with primary gateway. The primary gateway synchronizes the secondary and tertiary gateway with itself. If the primary gateway fails, secondary gateway takes up its place and if the secondary gateway fails tertiary gateway take up its place. This increases fault tolerance of WSN.