An energy-efficient routing protocol for UWSNs using physical distance and residual energy

In Underwater Wireless Sensor Networks (UWSNs), developing an energy efficient routing protocol is a challenge due to the peculiar characteristics of UWSNs. In this paper, we therefore propose an energy-efficient routing protocol, called ERP²R (Energy-efficient Routing Protocol based on Physical distance and Residual energy). ERP²R is based on a novel idea of utilizing the physical distances of the sensor nodes towards the sink node. ERP²R also takes into account the residual energy of the sensor nodes in order to extend the network life-time. Sensor nodes make a local decision of packet forwarding according to their physical distance and the residual energy information. Using the ns-2 simulator, we proved that the ERP²R protocol performs better than a representative protocol (i.e. DBR) in terms of energy efficiency, end-to-end delay and network lifetime.