Approximately, 4.6 billion people are connected to the internet through their mobile phones. For each of them, there are more than three devices communicating with the network. The Internet of Things (IoT) is made up of a growing number of connected objects: today there are 15 billion and by the end of the decade, there will be 30 billion. From cars to irrigation sensors, passing through weather stations in remote locations or autonomous drones, IoT is opening up countless new opportunities for communications and data. But it also has considerable obstacles to overcome.
One of the most important barriers is how to connect objects to the internet in places where there is no mobile network infrastructure. The answer seems to lie in Low Earth Orbit (LEO) satellites, although the solution is not without its own challenges. A new study, led by two researchers from the Universitat Oberta de Catalunya (UOC), Guillem Boquet and Borja Martínez, from the Wireless Networks group (WINE) at the Internet Interdisciplinary Institute (IN3), analyzes how to improve coordination between the billions of connected objects on the Earth’s surface and the satellites orbiting our atmosphere.
The explosive growth of the Internet of Things in the last decade has driven innovation in various fields, from logistics and smart cities to agriculture and maritime transportation. The IoT revolution has been largely sustained thanks to the efficiency of Low Power Wide Area Networks (LPWAN) and the terrestrial infrastructure built for mobile telecommunications. However, this efficient solution has a gray area: how to connect IoT devices in remote and rural areas where such infrastructure does not exist.
In recent years, LEO satellite constellations have emerged as an alternative solution that allows overcoming the limitations of terrestrial networks. “LEO satellites are especially relevant for IoT, as they require less transmission power to achieve reliable communication being closer to Earth. This allows devices to save energy, extend battery life, and reduce maintenance costs,” explains Guillem Boquet. “Among other advantages, deploying a satellite in low Earth orbit has a considerably lower cost, enabling connectivity services to be offered at more suitable prices for the IoT context.”
Furthermore, LEO satellites such as SpaceX’s Starlink, Eutelsat OneWeb, or Amazon’s Kuiper project allow for much lower latency (the delay between communications) compared to geostationary satellites, have many more satellites in operation and wider coverage, have a much shorter deployment time, and are suitable for communications in various sectors. However, their use for IoT is not without challenges.
Using satellites as part of the IoT network has its own barriers. Some are related to industry development itself (the deployment of satellite megaconstellations to ensure continuous coverage does not seem likely in the short term due to their low profitability in the IoT context), and others are related to restrictions derived from the technology’s design, such as the increased probability of interference between communications, limitations on energy usage by IoT devices, and difficulties in synchronizing IoT device work cycles with satellite communication availability intervals.
“IoT devices typically operate on battery and have activity cycles to wake up and power down at regular intervals to conserve energy. These periodic activity cycles are common in terrestrial communications and are even standardized. However, LEO constellations do not provide continuous coverage, so the communication windows are irregular and short-lived,” notes Guillem Boquet. “This makes it necessary to develop more advanced synchronization strategies to ensure reliable communication and access to the connectivity opportunities offered by the satellite network.”
The solution proposed by the UOC researchers was tested with a real communication case with the Enxaneta nanosatellite, the first satellite of the Generalitat de Catalunya within the NewSpace project. The results were promising: it improves the satellite access ratio by up to 99% and ensures long-term network access, minimizing the device’s energy consumption.
“The next steps are to complete the cost-benefit analysis of implementing this solution, considering various applications, service networks, types of satellite constellations, IoT devices, and communication technologies, and propose and implement energy-saving modes that automatically adapt to communication demands and variable conditions of non-terrestrial networks,” concludes the researcher.
Source: Boquet, G.; Martínez, B.; Adelantado, F.; Pagès, J.; Ruiz-de-Azua, J. A.; Vilajosana, X. Low-Power Satellite Access Time Estimation for Internet of Things Services Over Nonterrestrial Networks. In: IEEE Internet of Things Journal. Vol. 11, no. 2, pages 3206—3216, January 15, 2024, doi: 10.1109/JIOT.2023.3298017.
Press Release from UOC by Guillem Boquet, Researcher at the Wireless Networks (WINE) group, IN3 at UOC, and Borja Martínez, Researcher at the Wireless Networks (WINE) group, IN3 at UOC.