A cross-correlation based node estimation technique in underwater wireless communication network

Effectiveness of an underwater sensor network depends on the number of operating nodes, energy efficiency, and the lifetime of the network. So, the number of active nodes plays a vital role in system performance. But, in underwater harsh environment the number of operating nodes vary frequently with time due to various artificial and natural reasons (for example, failure of some nodes, some could be damaged, or batteries might fail). So, it is a matter of great interest for a communication network to know how many operating nodes or transmitters are available in the region at any point in time to ensure proper network operation (such as routing) as well as network maintenance. In this paper a simple node estimation technique based on the cross-correlation of the acoustic signals received at three sensors in the network has been proposed. The nodes are considered as acoustic signal sources and their number is obtained through the cross-correlation of the acoustic signals received at three sensors in the network. The mean 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 proposed approach.