Multi-Objective Routing Optimization to Support IoUT Applications in UWSNs

The Internet of Underwater Things (IoUT) is an emerging field of the Internet of Things (IoT) that extends IoT technologies to ocean environment. Recently, underwater wireless sensor networks (UWSNs) have shown great potential in IoUT and are envisioned to facilitate various IoUT applications. Considering the broad categories of IoUT applications, the routing protocol in UWSNs is expected to provide data transmission with different requirements. However, due to potential conflicts between different requirements of IoUT applications, most existing work only takes a certain requirement into account to optimize the corresponding transmission objective, which is often achieved at the cost of other requirements. To address this problem, a multi-objective routing (MOR) protocol is proposed in this paper to cater to the diverse demands of IoUT applications simultaneously. Specifically, the MOR protocol considers three key requirements in IoUT applications enabled by UWSNs, i.e., energy consumption, end-to-end delay, and link quality, to formulate the multi-objective routing optimization problem. Additionally, this paper also considers link congestion as an optimization objective to avoid frequent use of the local optimal communication links. Then, to solve the multi-objective routing optimization problem, a heuristic scheme based on the non-dominated sorting genetic algorithm II (NSGA-II) is proposed. Simulation results have shown the feasibility and effectiveness of the proposed MOR protocol and verified the necessity of multi-objective optimization in IoUT.