# Marine Internet for Internetworking in Oceans: A Tutorial
## 4 Communication Systems in Oceans
### Cabled Underwater Observatory System  
Several cabled underwater observatory systems have been deployed, typically including Monterey Accelerated Research System (MARS) in USA, Ocean Networks Canada (OCN), Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET) in Japan, and the European Multidisciplinary Seafloor and water column Observatory (EMSO).  
All these systems use sea-floor cables for both data communication and electrical power supply to support long-term real-time monitoring of processes related to geosphere, biosphere, and hydrosphere interactions. They are high-technology platforms hosting sensors to monitor temperature, pH, salinity, water circulation, seabed movements, etc., and provide services to the industry and fundamental for oceanic multidisciplinary research.  
As illustrated in Figure 4, MARS uses a 52-km undersea power and optical fiber to carry electricity power and data to a science node, which is located 891 m below the surface of Monterey Bay and connected to the shore through the cable. Other nodes can attach to this main hub, while additional experiments can be daisy-chained to each node [55]. OCN consists of two underwater observatories: the 800-km NEPTUNE and the nearly 50-km VENUS with four community observatories and seven shore stations [56]. It provides stream live data from instruments at key sites off coastal British Columbia via the Internet to the users around the world. DONET is a submarine real-time seafloor observatory network to monitor earthquake and tsunami, using 20 sets of submarine cabled sub-sea measurement instrument deployed 15-20 km apart with five science node interfaces [57]. EMSO is based on a European-scale network of multidisciplinary seafloor observatories, consisting of regional  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Systems**} & **Transmission** & **Transmission** & **Main** & **Typical** \\  & **Rate (Mbps)** & **Range (km)** & **Standard** & **Product** \\ \hline WiMax (4G) & 30–40 & \(\leq\)50 & IEEE 802.16 series & Intel WiMAX 6150 [52] \\ \hline True 4G \({}^{*}\) & 75(U), 300(D) & \(\leq\)100 & LTE IMT-Advanced & Huawei eWBB LTE [51] \\ \hline
5G & 10\({}^{3}\)-\(2\times 10^{4}\) & Several & IMT-2020 & Huawei 5G NR [53] \\ \hline \hline \end{tabular}  
* for 10–66 GHz Long-Term Evolution (LTE).  
\end{table}
Table 6: Advanced mobile communication systems.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**G**} & \multirow{2}{*}{**System**} & **Bandwidth** & **Frequencies (MHz)** \\  & & **(MHz)** & **(Example)**\({}^{*}\) \\ \hline
1G & AMPS & 50 & 824–849(U), 869–894(D) \\ \hline
2G & GSM & 50 & 935–960(U), 890–915(D) \\ \hline
3G & IMT-2000 & 145 & 1900–1980, 2010–2015, 2110–2170 \\ \hline
4G & LTE-Advanced & 140 & 2500–2570(U), 2620–2690(D), EU \\ \hline \hline \end{tabular}  
* The frequencies may vary for different regions and countries. G, Generation; U, Uplink; D, Downlink.  
\end{table}
Table 7: Radio spectra licensed to mobile cellular systems [20].  
facilities placed at key sites from the northeast to the Atlantic, through the Mediterranean, to the Black Sea. They constantly measure different biogeochemical and physical parameters related to natural hazards, climate change and marine ecosystems [58].