Maritime Wireless Communication: From Propagation to Multi-User Network Topoplogies

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Maritime wireless communication is strategic; as such it has a long history of scientific endeavors. In the past years, we have been solicited by numerous partners, such as the Canadian Navy, to provide reliable and high-speed oversea communications. By using astute multiple antenna schemes, we have enhanced by orders of magnitude the achievable data rates overwater. However, most long range measurement campaigns, performed by others and us, show significant discrepancies between received power predictions and actual measurements. A well-studied, but still somewhat elusive, ducting effect on the propagation is caused by the gradient of refraction index induced by the evaporation layer above the sea. For example, on the great barrier reef in Australia, with a non-line-of-sight link of 70 km, the yearly average power is a thousand times less powerful than predicted, the variations are not even correlated with the wind, as the theory predicts. In the NSERC Ultra Electronics chair's last campaign, we also had an unexpected and unbelievably good non line-of-sight link at 66 km. If one wishes to design a maritime network, a compensation of unknown effects through increased power is not possible since it also involves more interference on the global network. Going back to RF propagation basics is thus imperative on this issue. We thus propose to have an in-depth observation of the wireless link and the effect of waves in the reflection process. In fact, we believe that when the range is long, the grazing angle is so low that only a small number of sea waves effectively produce reflection and diffraction. This hypothesis is in stark contrast to the usual assumption of a scattering area. We propose to compute the propagation with sub-degree grazing and a random generation of directional sea waves. An actual radio measurement will be set-up to confirm the results by correlating real-time wave measurements of sea wave heights and the received signal power. At the network level, stochastic geometry and various network topologies are examined to predict the overall performance of networks with variable node densities. It is proposed to evaluate the achievable throughput for different distributions of ship positions and antenna heights, over multiple sea conditions. In terms of topology, a combination of meshed or Ad-Hoc, point-to-point and point-to-multipoint systems will be considered to maximize the possible Heterogeneous Network (HetNet) performance. The sea is of central importance to Canada and Québec as emphasized recently by both governments investing 2 B$ in maritime strategies. It is worth noting that Ultra electronics TCS has been founded as the Canadian Marconi Company by Sir Giuseppe Marconi in 1903, renowned for oversea wireless communication with the Titanic and as the first recipient of a Radio related Nobel Prize. This proposal is completely aligned with our historical wireless inventiveness.