An efficient depth-adjustment deployment scheme for underwater wireless sensor networks

Underwater Wireless Sensor Networks (UWSNs) have attracted significant research attention because of the broad application prospects. Unlike a terrestrial network, an underwater sensor network is a three-dimensional (3-D) network and it has peculiar characteristics such as low available bandwidth, large propagation delays, limited energy, etc. Also, complexity of the underwater environment brings about new challenges in node deployment issue. In this paper, a depth-adjustment deployment scheme based on Voronoi diagrams is proposed. It aims to maximize the sensing coverage and behave well in the network lifetime. The nodes are initially deployed on the surface of the water randomly and they can only move in vertical direction in 3-D space. Based on Voronoi diagrams, we find out the scheduling nodes whose disappearance will not decrease the sensing coverage in the current plane. Then let the scheduling nodes move vertically towards to the determined depth. As a result, our scheme divides the target region into different layers and the whole deployment process is simplified. Simulation experiments turn out that our scheme has a good performance in network sensing coverage and connectivity, also it outperforms random and optimal node deployment in the network lifetime.