# State of the Art of Telecommunication Systems in Isolated and Constrained Areas
## 2 Telecommunication Systems in an Isolated and Constrained Environment
### The Flying Systems
#### 2.3.1 The Balloons  
The \"balloon\" solution [30] consists of future projects such as the Loon balloon [31] or the Stratobus. The Loon balloon (Figure 5) is a project by Google X, a subsidiary of Google. In 2013, in a context where 2/3 of the world population has no Internet access or very low-speed access, Google decided to create a long-term ring of connectivity around the world [32] to bring Internet access to the most remote areas of the globe. The solution adopted was to use helium-inflated balloons [33], which carried LTE antennas [34] ensuring 3G/4G speed and a rigid photovoltaic panel. These balloons take off from the ground and climb up to the stratosphere at 20,000 m, above the airliners' altitude. They move according to the winds and are controlled and piloted from a ground control room. Thus, it is possible to converge several balloons in a sector and, therefore, ensure a covered area from a network point of view of the order of 1200 square kilometers. Figure 4: Nunavik’s optical fiber network. Figure 5: The Loon balloon [35]. This solution's effectiveness was demonstrated during the tragic event of the hurricane in Puerto Rico [36] in October 2017. There were no longer any connections and people were in grave danger. Google deployed its balloons and local phone operators collaborated. This enabled many distressed people to find a hint of enough connectivity to send an SMS or an email alert. They were thus able to be located and saved. The payload that can be loaded is around 40 kg. Before the deployment in Puerto Rico, proof of autonomy had been carried out through a 187-day flight, with difficult conditions, as the balloon suffered winds of 220 km/h. Thirty balloons were launched in 2013 from the southern hemisphere and New Zealand. Google is continuing its deployment with extensions in countries in the southern hemisphere such as Chile, Uruguay, and South Africa. This project is under development. One cannot connect of one's own will. There will probably be agreements forged with telephone operators, but the costs are not known yet. Therefore, this solution will not be available to everyone soon, and it will probably not be suitable for all situations. It can also be expected that the cost of connecting intelligent objects or sensors to the autonomous telecommunication station in an isolated environment will probably be high. Thus, this type of balloon is not a solution for the autonomous telecommunication station. Nevertheless, it is be a good starting point for the solution proposed later. In the same register as these flying telecommunication systems, we cite the Stratobus developed by the Thales company in collaboration with other companies like MMIST in Canada [37], shown in Figure 6. It is an airship of 115 m long and 34 m in diameter that carries between 250 kg and 400 kg loads. It has flexible photovoltaic panels [38] on a section of its wing. A solar concentrator associated with a ring surrounding it allows the Stratobus to be permanently oriented towards the sun for better energy efficiency. The airship by Thales presents several options: it moves in the stratosphere [40] at an altitude of 20,000 m using electric motors and its autonomy in flight allows it to carry out missions of 5 years without maintenance. Moreover, there is no need for a launcher, and a control room on the ground enables its repositioning. It is planned to be deployed in 2025 to carry out land and sea surveillance. An intelligent system [37] will allow the photovoltaic panels integrated into its wing to be permanently facing the sun giving it flight autonomy of 5 years. Surveillance missions should quickly identify areas affected by natural disasters (land surveillance) and limit maritime piracy by strengthening the AIM identification system (maritime surveillance). Its deployment will also allow environmental management by monitoring the water's cleanliness and the level of CO\({}_{2}\) in the air. Its power in terms of the onboard telecommunication system will allow 5G communication.