Underwater acoustic networks have many distinct channel characteristics when compared to terrestrial networks. Long propagation delay, one such characteristic, allows scheduling methods with varying granularity that tradeoff schedule quality with protocol overhead. This work examines several channel scheduling methods to determine at what point protocols find the best balance between performance and overhead. To accomplish this, five scheduling options are detailed and then compared through numerical and simulation results between themselves and to other protocols. The results indicate that scheduling links provides the best performance for the resource investment and that other scheduling options either require significant overhead or provide insufficient performance. While the results show that direct sequence spread spectrum techniques, common at the physical layer in underwater networks, do not yield an improved schedule, they do reduce protocol overhead and scheduling complexity by reducing conflicts in the network.
['Kurtis B. Kredo', 'Prasant Mohapatra']
Scheduling granularity in underwater acoustic networks