Geographic and Enhanced Opportunistic Routing for Underwater Sensor Networks

Underwater acoustic communication is a suitable method that facilitates underwater applications. However, the dynamic underwater acoustic environment poses many challenges, such as the three-dimensional expensive energy constraint deployment of nodes, the limited bandwidth, and the movement of nodes due to water currents. This leads to a void hole in the under aquatic region and affects the network performance in terms of packet ratio and energy consumption. To address these issues, we propose two routing protocols named Pro-GEDAR and GEEDAR for under acoustic communication that route data packets from sensor nodes to sonobuoys via opportunistic geographic routing. When a communication void hole occurs, both methods switch to recovery mode instead of using control messages to analyze and discover routing paths along the communication void hole region. The recovery mode procedure relies on the topology control information through improved depth adjustment of the void nodes with a proactive approach. The method significantly improves network performance in sparse and dense distributed networks with maximum traffic load. Our experimental results prove that the performance of our routing protocols is better in terms of fraction of void node, depth adjustment and packet delivery ratio compared to other schemes.