Propagation Channel for Communications and Navigation Between Moving Ships

This paper describes a geometric stochastic channel model that is used to analyse maritime communication and navigation services between ships on a dynamic sea-surface. The roughness of the sea surface impacts the propagation by the reflected sea surface and by the changing antenna heights. The impact is noticeable in communications by varying capacity and fluctuations data rates. In navigation the impact is two-fold, first the ranging performance is harmed by the varying received power levels and second by ranging dependent propagation channel models. For broadband systems sub-6 GHz spectrum is currently the focus of emerging maritime 5G networks. Further, we adapted the propagation conditions to the VHF channel propagation conditions to understand the impact in typical VHF systems, such as the AIS or the emerging VDES systems. Furthermore, the movement conditions of the transmitter and receiver on the ship change in all three dimensions depending on the sea state. The data collected from several measurement campaigns in different areas were used to analyse the propagation conditions over the sea by varying the sea surface roughness, the antenna heights and the bandwidths used, as well as the additional propagation conditions over the nearby land. The influence of the changing antenna height on the ship due to the sea conditions affects the reflection and scattering conditions.