Energy-efficient scheduling and hybrid communication architecture for underwater littoral surveillance

There exists a high demand for reliable, high capacity underwater acoustic networks to allow efficient data gathering and information exchange. This is evidenced by significant research in overcoming the limitations of the shallow water acoustic channel, such as low bandwidth, highly varying multipath effects and large propagation delays. This paper proposes an energy-efficient scheduling mechanism for a scalable network topology with a hybrid RF-acoustic communication architecture, designed for underwater littoral surveillance applications. In combination with a scalable buoy positioning scheme that assures AUV underwater synchronization and position computation, we propose a Time Division Multiple Access scheduling technique for underwater communication that achieves energy-efficient, collision-free data exchange on the low data rate acoustic channel. We measure the performance of the communication architecture by extensive simulations using the Opnet network simulator.