by About one-third of the world’s population, around 3 billion people, do not have access to the internet or have weak connections due to infrastructure limitations, economic inequalities and geographic isolation.
Today’s satellites and ground-based networks leave communication gaps where, due to geography, it would be too expensive to set up traditional ground-based communication equipment.
High-altitude platform stations – telecommunications equipment placed high in the air, on unmanned balloons, airships, gliders and airplanes – could increase social and economic equality by bridging internet connectivity gaps in terrestrial and satellite coverage. This could allow more people to fully participate in the digital age.
One of us, Mohamed-Slim Alouini, is an electrical engineer who helped with an experiment that showed high data rates and ubiquitous 5G coverage can be provided from the stratosphere. The stratosphere is the second lowest layer of the atmosphere, between 4 and 30 miles above the Earth. Commercial airplanes usually fly in the lower part of the stratosphere. The experiment measured signals between platform stations and users on the ground in three situations: someone staying in one place, someone driving a car and someone operating a boat.
My colleagues measured how strong the signal is in terms of interference and background noise levels. This is one of the measures of network reliability. The results showed that the platform stations can support high data rate applications such as streaming 4K resolution video and can cover 15 to 20 times the area of standard terrestrial towers.
Early attempts by Facebook and Google to commercially deploy station platforms were unsuccessful. But recent investments, technological improvements and interest from traditional aviation companies and specialized aerospace startups could change the equation.
The goal is global connectivity, a reason the platform station idea was recognized in the World Economic Forum’s 2024 report on the 10 Emerging Technologies. The international industry initiative HAPS Alliance, including academic partners, is also pushing towards that goal.
Fast, cost effective, flexible
Platform stations would be faster, more cost-effective and more flexible than satellite-based systems.
Because they keep communication equipment closer to Earth than satellites, the stations could offer stronger signals with higher capacity. This would enable real-time communication fast enough to communicate with standard smartphones, high-resolution capabilities for imaging tasks and greater sensitivity for sensing applications. They transmit data through free-space optics, or light beams, and large-scale antenna array systems, which can send large amounts of data quickly.
Satellites can be vulnerable to eavesdropping or jamming when their orbits take them over rival countries. But platform stations remain within one country’s airspace, reducing that risk.
High-altitude platform stations are easier to deploy than satellites, which have high launch and maintenance costs. And the regulatory requirements and compliance procedures needed to secure spots in the stratosphere are likely to be simpler than the complex international laws governing satellite orbits. Platform stations are also easier to upgrade, so improvements could be implemented more quickly.
Platform stations may be less polluting than satellite mega-constellations because satellites rise on reentry and can release harmful metals into the atmosphere, and platform stations can be powered by clean energy sources such as solar and green hydrogen.
The main challenges for practical platform stations are to increase the amount of time they can stay aloft to months at a time, boost green power on board and improve reliability – especially during automated take-offs and landings through turbulent layers lower in the atmosphere.
Over satellites
Platform stations can play a critical role in emergency and humanitarian situations by supporting relief efforts when ground networks are damaged or inoperable.
The stations could also connect Internet of Things (IoT) devices and sensors in remote locations to better monitor the environment and manage resources.
In agriculture, the stations could use imaging and sensing technologies to help farmers monitor crop health, soil conditions and water resources.
Their high-resolution imaging capabilities could also support navigation and mapping activities critical to cartography, urban planning and disaster response.
The stations could also do double duty by carrying instruments for atmospheric monitoring, climate studies and remote sensing of Earth’s surface features, vegetation and oceans.
From balloons to airplanes
Platform stations could be based on different types of aircraft.
Balloons offer long-term stable operation at high altitudes and can be tethered or unfloated. Aircraft, also known as dirigibles or blimps, use gases that are lighter than air and are larger and more maneuverable than balloons. They are particularly suitable for surveillance, communication and research.
Gliders and powered aircraft can be controlled more precisely than balloons, which are sensitive to variations in wind speed. In addition, powered aircraft, including drones and fixed-wing aircraft, can provide electricity for communications equipment, sensors and cameras.
Power for the next generation
Platform stations could use a variety of power sources, including increasingly lightweight and efficient solar cells, high-energy batteries, green hydrogen internal combustion engines, green hydrogen fuel cells, which are now in the testing phase, and finally, laser beam power. from solar stations on the ground or in space.
The evolution of light aircraft designs along with advances in high-efficiency motors and propellers enable airplanes to fly longer and carry heavier payloads. These pioneering light aircraft could lead to platform stations capable of moving in the stratosphere for long periods.
Meanwhile, improvements in stratospheric weather and atmospheric models have made it easier to predict and simulate the conditions under which the platform stations would operate.
Bridging the global digital divide
Commercial deployment of the platform stations, at least in post-disaster or emergency situations, could be in place by the end of the decade. For example, a consortium in Japan, a country of remote mountainous and island communities, has earmarked US$100 million for high-altitude solar-powered platform stations.
Platform stations could bridge the digital divide by increasing access to critical services such as education and health care, providing new economic opportunities and improving emergency response and environmental monitoring. As advances in technology continue to drive their evolution, platform stations will play a vital role in a more inclusive and resilient digital future.
This article is republished from The Conversation, a non-profit, independent news organization that brings you facts and analysis to help you make sense of our complex world.
Written by: Mohamed-Slim Alouini, King Abdullah University of Science and Technology and Mariette DiChristina, Boston University.
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Mohamed-Slim Alouini received many grants mainly from his own university to work on theoretical aspects of non-terrestrial networks (including HAPS and Satellite networks). He is also an academic member of the HAPS Alliance https://hapsalliance.org/ to stay in touch with practical developments in the field of HAPS.
Mariette DiChristina does not work for, consult with, share in, or be funded by any company or organization that would benefit from this article, nor has she disclosed any material affiliations beyond her academic appointment.
