# An Overview of Emergency Communication Networks
## 5 Sea Ad Hoc Network (SANET)
### Future Development Directions
#### 3.4.2 Space-Air-Ground-Sea Integration Networks
With the characteristics of easy deployment and efficient capture of high-resolution images, UAV technology is an effective solution for emergency communication, disaster reduction, management, and recovery. The UAV sends the collected data to the disaster area to enable appropriate decisions to be made and necessary actions to be taken in real time. [PERSON] et al. [128] studied the feasibility of a UAV-assisted emergency network in a large-scale disaster. [PERSON] et al. [129] proposed a four-axis aircraft for emergency medical care. [PERSON] et al. [130] collected real-time data by deploying wireless sensors on UAVs. [PERSON] et al. [42] designed and implemented an emergency network assisted by a UAV, which provides on-site monitoring, expands the existing Wi-Fi coverage through users' smartphones, and assists in search and rescue operations. Due to the advantages of rapid and flexible deployment of UAVs, the cooperative communication of the UAV cluster is an important part of the space-air-ground-sea integrated network. UAV communications can reduce the burden on ground networks and improve service capacity in congested areas with high dynamic data traffic loads. In addition, satellites/UAVs with remote sensing technology can support reliable acquisition of monitoring data and assist in effective resource management and planning decisions for ground networks [131]. The search for victims will be improved by adjusting the position of drones to adapt to actual disaster situations and exploring new areas to search for and rescue more victims. High-space networks, also known as \"high-altitude airships\", \"stratospheric platforms\", or \"atmospheric satellites\", have a wide coverage area, good channel characteristics, convenient deployment, and other advantages. High-space networks are deployed at an altitude of 17-22 km, including balloons, airships, and gliders. Ground-based network  
Ground-based networks mainly refer to ground fixed networks, ground mobile communication networks, and various types of terminals. Cellular mobile networks, vehicle networks, etc., are introduced in detail in Section 3.1. Sea-based network  
Sea-based networks use ships and buoys as platforms to quickly establish communication support and carry out rescue missions in the case of maritime emergencies or natural disasters. In the space-air-ground-sea integrated emergency communication system, the communication support ship carries a tethered UAV platform. This platform carries multiple relay communication loads to quickly reach the emergency sea area by taking advantage of the strong carrying capacity of the ship-borne system and the abilities to maneuver over long distances and remain for a long time. The system realizes the information communication between the rescue forces and the onshore command center, and lays a good technical foundation for joint cooperation in rescue work. The integrated space-air-ground-sea network uses TCP/IP technology to realize the interconnection of the Internet, mobile communication networks, and space networks, and to realize the unification of various applications on a common platform [132]. The network usually takes IP as the information carrying mode, combines technologies such as long-distance efficient transmission, signal processing, inter-satellite routing, and mobility management, and constructs a set of high-speed information networks covering the whole area based on the principle of the maximum effective comprehensive utilization of information resources. In the integrated space-air-ground-sea network, various networking technologies have advantages and disadvantages in terms of coverage, transmission delay, throughput, and reliability. Terrestrial cellular networks provide wide-area coverage with high data rates, but are extremely vulnerable to natural disasters (e.g., earthquakes, typhoons, and hail). In contrast, satellite communications can complement service access to ground networks in areas with limited or no ground network coverage, but the system capacity is limited.