Lifetime improvement of wireless sensor network by information sensitive aggregation method for railway condition monitoring

Lifetime maximization is an important issue while designing wireless sensor network. One of the ways to increase the lifetime of WSN is to reduce the energy demand of the sensor nodes and cluster head nodes, which can be decreased by filtering out redundant data traffic. A Two-Layer Hierarchal Aggregation (TLHA) protocol has been proposed, which filter out redundant data traffic. Simple aggregation algorithm has been used to classify the sensed data based on their normalized standard deviation for efficient data filtration. The algorithm also performs k-Means based re-classification of data to improve the efficiency of the algorithm. Two-layered redundant data filtration technique has been proposed to classify the data. Aggregation protocol reduces data traffic in lower layer hierarchy (sensor nodes to cluster head node) as well as upper layer hierarchy (cluster head nodes to base station node). In former, Energy efficient Time Division Multiple Access (EA-TDMA) Medium Access Control (MAC) protocol is used while in latter Bit-Map-Assisted (BMA) MAC protocol is used for transmission of data. Simulation and experimental results show that TLHA saves an enormous amount of energy, which finally increases the lifetime of the sensor network. The performance of the proposed TLHA protocol has been compared with already existing protocols viz. Data Aggregation Window Function (DAWF) and Spatial-Temporal Correlation Algorithm (STCA).