Transmission Range Adjustment for Void Hole Avoidance in UWSNs.

Underwater Wireless Sensor Networks (UWSNs) have captured interest of many researchers with the desire to control the large portion of the world overspread by water. Energy efficiency is one of the major concerns in UWSNs due to the limited energy of the underwater sensor nodes. In order to enhance the network lifetime, efficient and reliable protocols must be presented while considering the underwater acoustic communication challenges like low bandwidth, longer propagation delays and limited battery life of sensor nodes. In this paper, we present Modified Geographic and Opportunistic Depth Adjustment based Routing (MGEDAR) protocol to minimize the energy hole problem in UWSNs. Our protocol works by adaptively adjusting the transmission range of sensor nodes in case of void holes. Each node selects its forwarder on the basis of a cost function. Simulation results showed that our proposed scheme improves network performance in terms of maximum throughput, minimum energy consumption and reduced void holes.