Integrating Localization and Energy-Awareness: A Novel Geographic Routing Protocol for Underwater Wireless Sensor Networks

Underwater wireless sensor networks (UWSNs) are the enabling technology for a new era of underwater monitoring and actuation applications. While an efficient routing protocol for data packet delivery is crucial to UWSNs, design of such a protocol faces many challenges due to the characteristics of the acoustic channel used for communication. One of the challenges is high energy consumption by sensors in routing, which critically shortens the lifespan of the sensors involved in packet delivery. In this paper, we present a novel energy-efficient localization-based geographic routing protocol EEL, which uses location information and residual energy of sensor nodes to greedily forward data packets to sink nodes. EEL periodically updates the location information of nodes in an UWSN and effectively adapt to the dynamic topological changes of the network. EEL iterates through a list of candidate forwarding nodes by considering the NADV (Normalized Advancement) of these nodes that determines their transmission priority levels. Simulation results show that EEL can effectively locate sensor nodes while significantly improving the packet delivery ratio and reducing the energy consumption in a routing process as compared to other routing protocols used by UWSNs.