A reliable and energy-efficient routing protocol for underwater wireless sensor networks

Recently, underwater wireless sensor networks (UWSNs) have attracted much research attention to support various applications for pollution monitoring, tsunami warnings, offshore exploration, tactical surveillance, etc. However, because of the peculiar characteristics of UWSNs, designing communication protocols for UWSNs is a challenging task. Particularly, designing a routing protocol is of the most importance for successful data transmissions between sensors and the sink. In this paper, we propose a reliable and energyefficient routing protocol, named R-ERP²R (Reliable Energy-efficient Routing Protocol based on physical distance and residual energy). The main idea behind R-ERP²R is to utilize physical distance as a routing metric and to balance energy consumption among sensors. Furthermore, during the selection of forwarding nodes, link quality towards the forwarding nodes is also considered to provide reliability and the residual energy of the forwarding nodes to prolong network lifetime. Using the NS-2 simulator, R-ERP²R is compared against a well-known routing protocol (i.e. depth-based routing) in terms of network lifetime, energy consumption, end-to-end delay and delivery ratio. The simulation results proved that R-ERP²R performs better in UWSNs.