The Effect of Spreading Factor on Network Lifetime and Energy Consumption Rate of Low Energy Adaptive Clustering Hierarchy (LEACH)

Clustering is a widely discussed as an important architecture for data centric wireless sensor networks. Low energy adaptive clustering hierarchy (LEACH), proposed in past, is used as benchmark scheme by many proposals and its performance is widely studied in the literature, over last few years. The probabilistic and randomized clusterhead selection strategy results in variable number of clusterheads during different rounds of data gathering. To avoid communication interference in different clusters the signals need to be spread which results in increased data size. The variable number of clusterheads requires spreading factor to be set corresponding to the probable maximum number of clusterheads, to avoid collisions. This increases the data size and correspondingly the amount of energy required to transmit it to the base station. This directly affect the network lifetime and energy consumption of the sensor nodes, which are treated as important performance metrics for evaluation of many of the schemes proposed, in the literature, for data gathering in such networks. To study the effect of spreading factor on these performance metrics, LEACH scheme was simulated in NS-2. With the results obtained 8 is observed as an optimum value of the spreading factor for the simulated scenario, to achieve the desired performance in terms of network lifetime and energy consumption rate which demands development of a distributed clustering scheme with exactly equal number of clusterheads, during different rounds of data gathering.