# Moving Ad Hoc Networks--A Comparative Study
## 5 Sea Ad-Hoc Networks (SANET)
* Distress alerts from the 406 MHz satellite EPIRB are relayed by the Cospas-Sirsat polar orbit orbiting satellite and notified to the rescue coordination headquarters  
Figure 12: SANET architecture. via the land receiving station (LUT). The distress signal measures the position of the ship in distress. (d) Search and rescue information. Navigation warnings and weather warnings, which is maritime safety information, which is necessary for ship navigation, are provided by the Inmarsat High-Performance Group Call Receiver (EGC: built into the Inmarsat C-type equipment). Distress warnings (relays) from land to other vessels are also sent via the Inmarsat satellite to vessels or all vessels within a specific sea area. Table 6 shows the definition of the sea area. A distinctive feature of marine communication networks is the movement pattern for the conditions of the ship and sea level, and the received signal quality changes over time accordingly. (e) SANET applications. The SANET ad hoc network has many applications, as follows:  
* Disasters: The sea ad hoc network is helpful when natural disasters happen, such as oil barges capsizing, the sinking of the ship/boat, and the sinking of ferries carrying goods or people. * Weather: SANET is helpful to predict tsunamis or to track the water movements, and it utilizes different sensors for this application
* SANET can be used for search operation and release processes. * Military applications: SANET is very important for the exchange of information between headquarters and soldiers when they are in the ocean. The main concept of the SANET is the same as that of VANET, MANET, and FANET, but there are some differences in numerous approaches, such as power consumption, topology, speed, and alterations in deployment, etc. (f) The challenges of SANET include:
* Quality of Service (QoS): The maintenance of the best quality of service for packet forwarding is very important because it involves certain requirements, delays, throughput, and the packet error rate connected with the application. * Security: These requirements include rapidity, scalable authentication frameworks, and being lightweight, reliable, and secure. For information transfer, it is important to guarantee confidentiality and integrity. \begin{table}
\begin{tabular}{|c|c|c|c|} \hline
**Sear Area** & **Device** & **Communication Coverage** & **Technology** \\ \hline Sea Area A1 & & (20–30 nautical miles) & VHF-MF/DSC \\ \hline Sea Area A2 & & (400 nautical miles) & MF/DSC \\ \hline Sea Area A3 & & North latitude & \\  & & 70 degrees-South Latitude & INMARSAT/HF \\ \hline Sea Area A4 & & Worldwide & EPIRB/HF \\ \hline \end{tabular}
\end{table} 
Table 6: Definition of Sea Area. Scalability: The most important and necessary step toward the realization of effective ship communications is to guarantee a stable and scalable routing mechanism over SANETs. The routing paths are disrupted frequently due to varying ship mobility and network topologies, and it is very difficult to ensure their stability. * Routing protocol: There are large end-to-end delays and reduced packet delivery ratio. * Reliability: Because of the sensitive information we send, SANET must be very reliable. * Routing Protocols used in SANET. At present, several typical routing protocols are (Figure 13): DSDV (destination sequence distance vector routing protocol), TORA, DSR, OLSR, and AODV, etc. Based on the comparative analysis of the delay, delivery rate, and throughput among the classic protocols, the AODV protocol is more suitable for maritime communication. The steps of the protocol are described as follows:  
* First, the source node sends routing requests to the neighboring nodes. * After the surroundings receive the request, they will automatically form a virtual node. In this process, more than one node may receive the request, and these requested nodes are all unified virtual nodes. * The virtual node continues to send the routing request.