EEHR: Energy Efficient Hybrid Routing Protocol for Underwater WSNs

Energy is a main issue in Underwater Wireless Sensor Networks (UWSNs). The wireless sensor nodes in underwater network have limited source of energy (batteries) and replacement of their batteries is very difficult and costly. Hence, energy efficiency has always remained as a major concern in UWSNs. Moreover the variation in energy consumption of nodes reduces the network lifetime and creates network holes. Combination of multi-hop transmission and direct communication were proposed before to balance the energy consumption between nodes. Direct transmission of data packets to sink depletes more energy of sensor node as compared to multi-hop transmission. When The nodes which reside at a greater distance from the sink opt for direct communication, their energy rapidly decreases. Thus resulting in shorter network lifetime. This paper presents Energy Efficient Hybrid Routing Protocol (EEHR). This protocol is a hybrid between multi-hop and direct transmission to the neighbors residing in the sub neighbor region. In this paper the direct transmission distance is decreased and it is refined to a sub neighbor region, which increases the network lifetime and reduces the energy consumption of the network. There are 4 regions of different radii from the sink created in our proposed protocol. The regions are in the form of semi circles beneath the sink node. Equal number of nodes are deployed randomly in each region. Neighboring lists are created by the nodes on the basis of their optimum distance to the sink. Simulation results show improvement in the network lifetime and energy consumption of the network.