Bridging Energy Holes in Underwater Acoustic Sensor Networks: A Call for Adaptive Routing Protocols

Underwater Acoustic Sensor Networks (UASNs) has significantly attracted the attention of researchers with many of its uses in aquatic environments, such as tactical surveillance, pollution monitoring, underwater resource exploration, and catastrophe detection. An important and difficult problem with UASNs is the rapid depletion of energy due to the high power requirements for acoustic communication, while the battery capacity of the sensors is restricted. However, if the battery energy consumption is unbalanced, it can cause nodes to deplete their energy reserves quickly. This results in the formation of energy sink hole, which divide the whole network and damage the accuracy of the monitoring data. In severe cases, it may even cause the entire network to fail. However, ensuring that energy is evenly distributed across nodes may significantly increase the longevity of these networks. Therefore, it is imperative to implement energy-conserving protocols that can efficiently handle the restricted energy allocation while considering the distinctive characteristics of the underwater environment.