Extending Lifetime of Wireless Sensor Networks by Management of Spare Nodes

Extending lifetime of wireless sensor networks (WSNs) is one of the most critical issues in WSNs. Lifetime limitations are caused by limited energy resources. Significant extensions of WSN lifetime can be achieved by adding spare nodes. The spares are ready to be switched on when any primary (original) WSN node uses up its energy. We propose the LEACH-SM protocol, which modifies the prominent Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol by providing an optimal spare selection and energy-saving management of spares. We also provide a method for estimating WSN lifetime, which has a critical importance for planning WSN applications. The salient features of LEACH-SM include parallelism in running its component protocols, scalability, and reduced transmission of redundant data to cluster heads (collecting information from sensor nodes).