A Quantitative Comparison of Energy Consumption and WSN Lifetime for LEACH and LEACH-SM

Extending the period of operation (lifetime) of wireless sensor networks (WSNs) is one of the most critical issues. Their limitations are due to limited energy resources. Available research results reveal that significant improvement in WSN lifetime can be achieved by adding spares (spare nodes). At the moment of WSN deployment, the minimum required coverage of WSN targets is assured by the primaries (primary nodes). Spares, if activated, would provide an above-threshold (more than required), redundant target coverage, so can be switched off initially. They are ready to be switched on when any primary exhausts its energy. The spares must be properly managed. Mismanagement includes redundant and above-threshold coverage, which increase transmission of redundant data to cluster heads (collecting information from regular nodes, that is, primary nodes that are not cluster heads). Therefore, mismanaged spares can shorten WSN lifetime instead of extending it. To extend WSN lifetime, we propose the LEACHSM protocol, which modifies the prominent LEACH protocol by providing an optimal energy-saving spare management, including spare selection. LEACH-SM adds the spare selection phase to LEACH. This paper presents a quantitative comparison of energy consumption and WSN lifetime for both protocols.