The Research On Node Deployment Of Underwater Wireless Sensor Networks

Underwater Wireless Sensor Networks (UWSNs) have attracted significant research attention all over the world 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 thesis, the work we did are as follows:First, we analyze the node sensing model and do a lot of research on the deployment algorithms which had been done by researchers. Then, a depth-adjustment deployment scheme based on Voronoi diagrams and Delaunay triangulation is proposed. This scheme aims to maximize the coverage, connectivity 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. Then, we find out the scheduling nodes whose disappearance will not decrease the sensing coverage in the current plane. And next step 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 novel, simplified and efficient. 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. At the end of this paper, considering the effect of current, we analyze the node mobility models and then depending on these models, we evaluate the impact which the mobility models produced to the coverage of the underwater networks.