Leveraging AUV Trajectory Optimization for Robust Software-Defined Underwater Routing

Underwater networks are becoming a vital component of 6G networks. To integrate them with both terrestrial and non-terrestrial networks, it is necessary to address inherent challenges in stability, scalability, and efficiency. We propose a spectrum- and energy-aware software-defined underwater network (SEA-SDUN) framework to simultaneously overcome spectrum scarcity (specifically in acoustic networks), path instability, and energy constraints. To balance the load, a dual-layer SDN architecture is employed, where local controllers (LCs) manage local topologies, including updates for spectrum, available paths, and residual energy, providing intelligence and flexibility to the network, while a single surface-based main controller (MC) serves as a backup, maintains global topology, and manages the battery status of the nodes by serving as a charging station. SEA-SDUN addresses these issues by jointly optimizing link delay and energy consumption while also providing optimized trajectories for AUVs. Consequently, SEA-SDUN establishes the most optimal paths available between source and destination pairs, significantly improving the packet delivery ratio while reducing delay, overhead, and energy consumption compared to two reference schemes.