Recently, Underwater Wireless Sensor Networks (UWSNs) have attracted significant attention from both academia and industry to explore the vast underwater environment. Since UWSNs suffer from long propagation delay, low bandwidth, and high error rate, providing an efficient routing protocol is challenging. This paper proposes EEARP, a series of new routing protocols for underwater networks to improve the performance of existing DBR. The DBR does not consider energy. It only receives data packets from upper depth node and forwards the packets to lower depth nodes. Moreover, this greedy behavior of DBR causes void area problem. EEARP creates a directed acyclic graph rooted at a sink. Each node receives information like depth, energy, and the number of parents from its parents. When forwarding, each node sends a data packet to one or more of its parent nodes. We implemented EEARP in NS2 simulator and evaluated its performance under different scenarios. Results confirm that EEARP outperforms DBR in terms of energy saving, network lifetime, end-to-end delay and packet loss ratio.
