Multi-hop localization algorithm for large-scale underwater wireless sensor networks

Although localization has been widely studied for terrestrial Wireless Sensor Networks (WSNs), the adverse aqueous environments, the harsh acoustic communications, and the large network scale all pose new challenges for Underwater WSNs (UWSNs) and make it necessary to develop new localization algorithms. In this paper, we propose a novel Multi-Hop Localization Algorithm (MHLA) for large-scale UWSNs. First, we transform the three dimensional (3D) localization problem into its two dimensional (2D) counterpart by employing node depth information and a simple projection technique. Then, we construct a weighted constrained multi-hop localization model. Next, based on the geometric constraint relationship between nodes, the bounding square rings of to-be-localized nodes are designed to estimate the feasible region. Finally, we search the close to the optimal values of nodes' coordinates through a lightweight grid-scanning procedure. Simulation results show that our scheme can achieve high localization accuracy with low computational complexity in large-scale UWSNs.