A Voronoi-Based Optimized Depth Adjustment Deployment Scheme for Underwater Acoustic Sensor Networks

Node deployment plays a vital role in Underwater Acoustic Sensor Networks (UASNs) and is closely related to many network tasks, such as routing protocol design and topology control. Coverage and connectivity are two important indicators for node deployment. However, separately improving one of the indicators could lead to the decline of another indicator. Therefore, coverage and connectivity need to be jointly optimized. In this paper, we propose a Voronoi-based Optimized Depth Adjustment (VODA) deployment scheme to deploy sensor nodes in a target water space. First, gateway nodes collect the coordinates of sensor nodes to establish a Voronoi diagram. Based on this diagram, some of sensor nodes are selected to remain on the water surface, which are called leader nodes. The remaining nodes need to sink to different depths so that reduce the coverage overlap between the nodes. According to graph coloring theory, each sensor node is assigned a layer label (LID) which represents a relative position. Finally, the nodes calculate their depths in the order of LIDs from small to large. Simulation results show that compared with three other schemes, VODA can always get higher coverage in different cases, while the connectivity is maintained at 100 % in the proposed scenarios. Meanwhile, VODA can help the networks get a longer lifetime.