## 2 Data Transmission Requirements and Available Connectivity Technologies  
Current networks cannot yet fulfill requirements for the scalable, bidirectional communication needs of autonomous and remote-controlled vessels. The coming 5G and 6G networks will be integrated multi-connectivity technologies, i.e., enabling communications of a single user with two or more different network nodes with different radio access technologies (RATs). They are able to separate and prioritize resources, and use network slicing and virtual networks to efficiently support the application needs [20; 21; 22; 23]. Future systems will interwork, e.g., with public safety networks, satellites, and WiFi, so that services could be seamlessly provided to the end users with different radio interfaces. Some technologies are good for long-range communications such as geostationary (GEO) satellites that can provide services in almost all ocean areas. Low-earth-orbit (LEO) satellites are needed to cover the Arctic. However, when the ship is operating in coastal areas, it is usually relying on the terrestrial technologies that are presented in Table 2. Satellite technologies for deep-sea connections are shown in Table 3.  
The table shows that different technologies are suitable depending on the communication range, throughput and cost requirements. Some of the systems such as very high frequency (VHF) and digital high frequency (HF) are regularly used by the shipping industry. The 6G system estimations provide an initial view about the future systems coming during the next decade. The best connections for vessels can be achieved by an hybrid approach, i.e., integrating multiple radio technologies in the same system to make it fail safe and being able to connect in any environment. Some estimates for the data rate requirements are presented in Table 4, showing that most of the data demand is to transfer the situational awareness (SA) data from the ship to the remote operators. The control data sent to the ship is quite limited, in the order of kilobits per second, whereas the sensor data sent from the ship can easily be many megabits per second. People can interpret imperfect SA data and thus data processing can be used to compress and reduce the bit rate significantly [5]. However, the data rate requirements are clearly asymmetrical and there is a need to have high-throughput ship-to-outside connections. Thus, satellite systems also need to provide high-throughput uplink. \begin{table}
\begin{tabular}{c c} \hline \hline
**Topic of the Article** & **Contributions Given in the Article** \\ \hline \multirow{4}{*}{Autonomous Ship Connectivity: Standardization, Architecture and Simulations} & Novelty in this article: Updated technology survey for unmanned and remote-controlled surface vessels with future research directions. Both in-ship and ship-to-outside connections considered. Focus on 5G standardization, integrated satellite–terrestrial communications, and discussion on how to use ship simulators in connectivity research \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \cline{1-1}  & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._