Joint optimization of number of clusterheads and spreading factor for network lifetime of low energy adaptive clustering hierarchy

Low energy adaptive clustering hierarchy (LEACH) is widely discussed, in the literature, for energy efficient data centric wireless sensor networks. Due to its seminal nature it has emerged as a benchmark for performance comparison. For uniform energy consumption of sensor nodes, it suggests rotation of the clusterhead role after a fixed duration, with probabilistic selection of sensor nodes as clusterheads for successive rounds. However, this probabilistic approach does not guarantee selection of equal number of nodes as clusterheads during different rounds. LEACH uses DS-SS to allow simultaneous data transmissions in different clusters. The variable number of clusterhead requires the spreading to be used to be more than that required with desired number of clusterheads. Enough amount of additional spreading is suggested to be used to avoid inter cluster interference. The optimum number of desired clusterhead is shown to be within 1 to 6% of total nodes. This makes it interesting to optimize the desired number of clusterheads and the spreading factor jointly for network lifetime, the most important performance metric used for evaluation, of LEACH. So, this paper presents the results of the optimization carried out through simulation, of LEACH, of different number of desired clusterheads and additional spreading required for its network lifetime.