Exploiting Sink Mobility to Maximize Lifetime in 3D Underwater Sensor Networks

Network lifetime is crucial to 3D Under Water Sensor Networks (UWSNs) because it decreases more seriously than in 2D scenarios as the radius of the monitored region grows. We utilize sink mobility to solve the problem intuitively because the sink deployed in a vehicle is controllable while sensors are hard to be retrieved and recharged. It is hard to extend the results in 2D scenarios, i.e., a circular motion, to 3D UWSNs directly because there are more factors influencing network lifetime. However there is little literature on utilizing and analyzing sink mobility in 3D UWSNs. To simplify 3D sink mobility, we convert any motion to a combination of circular motions through mapping. After discussing the characteristics of circular motions, we propose MOSS, an optimal MObile Sink Strategy, to maximize the network lifetime in 3D UWSNs. Simulation results show that MOSS outperforms other motion strategies and improves the network lifetime at least in the order of 800\% when $R \geq 5r$, where $R$ is the network radius and $r$ is the transmission range of sensors.