Nearly a third of the world’s population, approximately 3 billion people, lack access to the internet or have poor connections due to infrastructure constraints, economic inequalities and geographic isolation.
Today’s satellites and ground-based networks leave communications gaps where, due to geographic location, traditional ground-based communications equipment would be prohibitively expensive to install.
High-altitude platform stations—telecommunications equipment positioned high in the air on uncrewed balloons, blimps, gliders, and airplanes—could increase social and economic equality by filling internet connectivity gaps in ground 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 contributed to an experiment that demonstrated that it is possible to deliver high data speeds and ubiquitous 5G coverage from the stratosphere. The stratosphere is the second-lowest layer of the atmosphere, located 4 to 30 miles above the Earth. Commercial aircraft typically fly in the lower stratosphere. The experiment measured signals between platform stations and users on the ground in three scenarios: a person standing on the ground, a person driving a car, and a person driving a boat.
My colleagues measured how strong the signal was relative to interference and background noise levels—one measure of network reliability. The results showed that the platform stations could support high-data-rate applications, such as 4K-resolution video streaming, and cover 15 to 20 times the area of standard terrestrial towers.
Initial attempts by Facebook and Google to commercially deploy platform stations have failed, but recent investments, technological advances, and interest from traditional aviation companies and specialized aviation startups could change the equation.
The goal is global connectivity, which is why the platform stations idea was recognized in the World Economic Forum’s Top 10 Emerging Technologies report for 2024. The HAPS Alliance, an international industry initiative that includes academic partners, is also working toward this goal.
Fast, cost-effective, flexible
Platform stations will be faster, more cost-effective and more flexible than satellite-based systems.
Because they hold their communications equipment closer together than satellites, the stations can deliver stronger, higher-capacity signals. This would enable real-time communications fast enough to communicate with standard smartphones, high-resolution capabilities for imaging missions, and greater sensitivity for sensing applications. They transmit data via free-space optics or large-scale antenna array systems that can send light beams and large amounts of data quickly.
Satellites can be vulnerable to eavesdropping or jamming when their orbits take them over hostile countries, but platform stations remain within a single country’s airspace, reducing this risk.
High-altitude platform stations are easier to install than satellites, which have high launch and maintenance costs. In addition, the regulatory requirements and compliance procedures required to secure points in the stratosphere will be simpler than the complex international laws that govern satellite orbits. Platform stations are also easier to upgrade, so improvements can be deployed more quickly.
Platform stations are also potentially less polluting than satellite mega-constellations because satellites burn up on re-entry and can release harmful metals into the atmosphere, while platform stations can be powered by clean energy sources such as solar and green hydrogen.
The key challenges facing practical platform stations are to extend their airborne endurance to months, increase green onboard power, and improve reliability; particularly during automatic takeoff and landing through the turbulent layers of the lower atmosphere.
Beyond satellites
Platform stations can play a critical role in emergency and humanitarian situations by supporting relief efforts if land-based networks are damaged or rendered inoperable.
The stations can also connect Internet of Things (IoT) devices and sensors in remote environments to better monitor the environment and manage resources.
In agriculture, stations can use imaging and sensing technologies to help farmers monitor crop health, soil conditions and water resources.
High-resolution imaging capabilities can also support navigation and mapping activities that are vital for cartography, urban planning and disaster response.
The stations could also serve double duty, carrying instruments for atmospheric monitoring, climate studies and remote sensing of Earth’s landforms, vegetation and oceans.
From balloons to airplanes
Platform stations can be created for different aircraft types.
Balloons offer stable, long-duration operation at high altitudes and can be tethered or free-floating. Airships, also known as blimps or balloons, use lighter-than-air gases and are larger and more maneuverable than balloons. They are particularly well-suited for surveillance, communications, and research.
Gliders and powered aircraft can be controlled more precisely than balloons, which are sensitive to changes in wind speed. Additionally, powered aircraft, such as drones and fixed-wing aircraft, can power communications equipment, sensors, and cameras.
New generation power
Platform stations could use a variety of power sources, including increasingly lightweight and efficient solar cells, high energy density batteries, green hydrogen internal combustion engines, green hydrogen fuel cells currently in the testing phase, and eventually laser beam powering from ground- or space-based solar stations.
The evolution of lightweight aircraft designs, combined with improvements in high-efficiency engines and propellers, allows aircraft to fly longer and carry heavier payloads. These cutting-edge lightweight aircraft could lead to platform stations that can maneuver in the stratosphere for extended periods.
Meanwhile, developments in stratospheric weather models and atmospheric models make it easier to predict and simulate the conditions under which platform stations will operate.
Closing the global digital divide
Commercial deployment of platform stations could happen by the end of the decade, at least for post-disaster or emergency situations. For example, a consortium in Japan, a country with remote mountainous and island communities, has set aside US$100 million for solar-powered, high-altitude platform stations.
Platform stations can bridge the digital divide by increasing access to critical services like education and healthcare, 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 key role in a more inclusive and resilient digital future.
This article is republished from The Conversation, a nonprofit, independent news organization that delivers facts and analysis to help you understand 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 has received several grants, mostly 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 HAPS field.
Mariette DiChristina does not work for, consult, own shares in, or receive funding from any company or organization that would benefit from this article, and has disclosed no affiliations beyond her academic appointment.