# Communication Technologies in Emergency Situations
## 4 Emergency Communications Technologies--A Systematic Literature Review
### Wired and/or Wireless Communications to Internet  
Ref. [35] is focused on a solution based on fuzzy logic for the routing decision problem for an underground mine wireless-communication. While most of its contribution affects the SR communications inside the underground mine, it also mentions the commonly used method of drilling in the blocking area and installing a wireless access point (AP) or gateway through the hole to connect the ground backbone network (Ethernet) with the emergency communication network in an underground mine, which could be used for the coordination communications (CIRS).  
Ref. [41] proposes a quick, efficient, and low-cost post-disaster wireless communication deployment whereby a truck-mounted BS is deployed to clusters of users within a disaster zone. It is assumed that the BSs do not have any form of backhaul capability to the core network and, as such, rely on a UAV to periodically come for a fly-by to receive the data from each BS and ferry it to the core network (represented by a gateway), or vice versa.  
Thus, BSs serve for SR communications in the clusters of users, but the main goal of the UAV in this work is to forward all the communications to the core network and thus prove useful for coordination purposes (CIRS). In the same line, in [43], Delay Tolerant Networks based on a regional centre node and a UAV as ferry node are proposed to build the post-disaster emergency communication network. However, in this case, the focus of the contribution is on the SR communication (exchange of information between the BSs), while the objective of communication with the core network is just briefly mentioned.  
Ref. [45] proposes Wi-Fi tethering to build ad-hoc subnetworks of disconnected smartphones in emergency areas. However, their solution implies an Emergency Command Centre (ECC) far away from the affected area, which coordinates not only the FRs, but also the proposed network deployment. In this line, some assumptions regarding the CIRS communications are described. In particular, the backhauls of the network consist of gateway devices, including smartphones with surviving/established cellular links and emergency APs, or surviving base stations and \"Cell On Wheels\" (COWs) in their limited coverage area. The COWs are mobile, portable cell towers and transceivers mounted on trailers or trucks for easy deployment in the affected areas. Furthermore, the emergency Wi-Fi APs are deployed in conjunction with the satellite gateways in the affected region. Each satellite gateway is composed of a very-small aperture-terminal (VSAT) dish antenna and a satellite modem that can be easily assembled and disassembled for portability. When the road connectivity is available, the Wi-Fi APs with satellite gateways are deployed at various locations in the affected region with the help of emergency vehicles. If no road connectivity is available in the affected region, then the equipment can be carried or air-dropped by emergency crews and deployed similarly. Since the APs are intended exclusively for assisting with the emergency network, they assume that they are pre-authenticated by the ECC and connected to the ECC using traditional technologies, such as satellite networks.