A Voronoi-based Depth-adjustment Scheme for Underwater Wireless Sensor Networks

Underwater wireless sensor network (UWSN) is a special kind of wireless sensor network which is composed of a large quantity number of wireless sensor nodes deployed in the water. While there are extensive studies on deploy-issue of terrestrial wireless sensor networks (WSN), UWSN has not been paid enough attention due to the challenges of UWSN, such as low available bandwidth, highly varying multipath, and large propagation delays. In this paper, we propose a depth-adjustment scheme to maximize the coverage in 3D space. After deploying nodes in the water surface, we use Voronoi diagram to compute redundant nodes whose disappearance will not decrease the coverage in 2D space, and then we determine the depth that redundant nodes should be moved towards. After all the redundant nodes have moved to the lower layer, the algorithm continues to schedule redundant nodes of the lower layer until 3D space coverage is fulfilled.