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

海上无线通信具有战略意义；因此，它具有悠久的科学努力历史。在过去的几年里，我们受到了加拿大海军等众多合作伙伴的邀请，提供可靠和高速的海外通信。通过使用巧妙的多天线方案，我们已经将水上可实现的数据速率提高了数量级。然而，其他人和我们进行的大多数远程测量活动显示，收到的功率预测与实际测量之间存在显著差异。海面上蒸发层引起的折射率梯度是传播过程中的一种已有研究，但仍有些难以捉摸的导流效应。例如，在澳大利亚的大堡礁上，非视距连接长达70公里，年平均功率比预测的要小一千倍，变化甚至与理论预测的风无关。在NSERC Ultra Electronics主席的最后一次活动中，我们也有一个出人意料的、令人难以置信的好的非视距链接，距离为66公里。如果一个人希望设计一个海上网络，通过增加功率来补偿未知影响是不可能的，因为这也涉及到对全球网络的更多干扰。因此，在这个问题上，回到射频传播基础上是当务之急。因此，我们建议对无线链路和反射过程中的波的影响进行深入观察。事实上，我们认为，当射程较长时，掠射角非常低，只有少数海浪才能有效地产生反射和绕射。这一假设与通常的散射区假设形成鲜明对比。我们建议在亚度掠过和随机产生定向海浪的情况下计算传播。将设置实际的无线电测量，通过将海浪高度的实时波浪测量与接收信号功率相关联来确认结果。在网络层次上，研究了随机几何和各种网络拓扑结构，以预测具有可变节点密度的网络的整体性能。建议评估在多种海况下不同船位和天线高度分布情况下的可实现吞吐量。在拓扑方面，将考虑网状或自组织、点对点和点对多点系统的组合，以最大化可能的异质网络(HetNet)性能。海洋对加拿大和魁北克至关重要，正如两国政府最近在海洋战略上投资20亿美元所强调的那样。值得注意的是，Ultra Electronics TCS于1903年由朱塞佩·马可尼爵士创立，前身为加拿大马可尼公司，以与泰坦尼克号的海外无线通信而闻名，并成为第一位获得无线电相关诺贝尔奖的人。这一提议与我们历史上的无线发明完全一致。

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.