MAC scheduling in large-scale underwater acoustic networks

The acoustic propagation speed under water poses significant challenges to the design of underwater sensor networks and their medium access control protocols. Scheduling allows reducing the effects of long propagation delay of the acoustic signal and has significant impacts on throughput, energy consumption, and reliability. In this paper we propose two approaches for scheduling large-scale underwater networks. One approach is a centralized scheduling approach, which yields the most efficient schedules but has significant communication and computational overhead. Our second approach uses clustering to split up the network in independent clusters. This approach provides significant benefits in terms of communication and computation, but yields less efficient schedules than the centralized approach. We evaluate both approaches in terms of efficiency, communication overhead and computation overhead of the resulting schedule. We show that the centralized approach yield the best schedule at the cost of significant communication and computation overhead. The distributed scheduling approach yield less efficient schedules but offers significant communication and computational complexity advantages.