REBAR: A Reliable and Energy Balanced Routing Algorithm for UWSNs

In this paper, we propose a reliable and energy-efficient routing algorithm for underwater wireless sensor networks (UWSNs). We first use a sphere energy depletion model to analyze the energy consumption of nodes in UWSNs. We then extend the model by considering the node mobility in UWSNs. Our analysis is in accordance with the common view that although water flows might cause the underwater environment more dynamic, this instability can actually improve energy-efficiency. However, the nodes closer to the sink still tend to die early, causing network partition around the sink. Accordingly, we propose a Reliable and Energy BAlanced Routing algorithm (REBAR). We explore the tradeoff between packet delivery ratio and energy efficiency. We design an adaptive scheme for setting data propagation range in order to balance the energy consumption throughout the network. Multi-path routing is used to provide redundancy. We further extend REBAR to deal with possible routing voids in the network which could be common in UWSNs. Simulation results show that our protocol outperforms existing VBF-based approaches in terms of reliability and network lifetime.