A study on channel dynamics representation and its effects on the performance of routing in underwater networks

We consider an underwater networking scenario, and test the performance of two multihop routing paradigms, source routing and hop-by-hop relay selection, in the presence of different representations of the channel dynamics. We focus on a static channel case (obtained via empirical equations for path-loss), and on a sequence of channel realizations obtained using ray tracing, that vary both slowly and rapidly over time with respect to the expected reaction time of routing protocols; the two latter cases are also explored in the presence both of a flat bottom and of a rough bottom with several seamounts, to yield a total of five different channel models. Our results show that channel variations induced by environmental changes over time have an impact on routing performance metrics in connected topologies. A sea bottom with a rough shape adds a further impact to the routing performance, which is shown to be larger for source routing. We conclude that while empirical channel models yield a good first-order approximation, the time-variability of the channel and the shape of the network area boundaries are to be taken into account in order to achieve more realistic network performance estimates.