A node estimation technique in underwater wireless sensor network

The number of nodes in a deployed wireless sensor network might vary due to ad hoc nature, natural disaster. Counting the number is very important in useful data collection, network maintenance, node localisation. Although protocols are being used to count the number in terrestrial networks, harsh environment limits their use in underwater networks. A statistical signal processing approach of node estimation is proposed in this paper. The nodes are considered as acoustic signal sources and their number is obtained through the cross-correlation of the acoustic signals received at two sensors in the network. The ratio of mean and standard deviation of the cross-correlation function is related with the number of nodes and used as the estimation parameter in the process. Theoretical and simulation results are provided which shows effectiveness of the signal processing approach instead of protocols in node estimation process.