Stratospheric Platforms Limited (SPL)
Superlatives Reign: Beaming 5G from the Stratosphere via New Type of Wireless Antenna
“5G sky high” is in the mind’s eye of Deutsche Telekom, which has backed UK-based startup Stratospheric Platforms Limited (SPL) and Capgemini-owned Cambridge Consultants to develop and test an airborne 5G network, slated for commercial release in 2024.
SPL said it has developed a high-altitude platform (HAP), in the shape of an unmanned zero-emissions aircraft, to carry a new kind of wireless antenna designed by Cambridge Consultants – which is described as 
“unlike anything seen before.” The two startups believe they can provide 5G coverage to the entire UK, from 20,000 metres up, from an airborne antenna array mounted on just 60 aircraft. They say that Germany with 67 aircraft.
HEALTH WARNING: It’s important to note that there is no standard, nor any standards or specifications work we know of related to airborne 5G via HAPs. The IMT 2020.SPECS and 3GPP 5G NR specs only address terrestrial coverage. In particular, IMT 2020.SPECs: “Detailed specifications of the terrestrial radio interfaces of International Mobile Telecommunications-2020 (IMT-2020).”
Also, the frequencies for such a “HAP based 5G” have not been specified by WRC 19 or ITU-R. However, ITU-R identified the following frequency bands for HAPs use: worldwide (31-31.3 GHz, 38-39.5 GHz, 47.2-47.5 GHz, and 47.9-48.2 GHz) and Region 2 (the Americas) (21.4-22 GHz and 24.25-27.5 GHz).
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The Capgemeni press release states:
Operating at a fraction of the cost of building and maintaining terrestrial infrastructure, and with minimal environmental impact due to its zero-emission hydrogen power system, such a fleet could rewrite the economics of mobile broadband.
With the proof of concept now complete, the ultimate antenna is set to be powerful, huge, and yet lightweight. At three meters square and weighing just 120kg, it will take flight to become what’s expected to be the world’s largest commercial airborne communications antenna.
The proof of concept antenna is the culmination of a four-year project with UK-based start-up SPL. Also headquartered in Cambridge, UK, SPL is developing a High-Altitude Platform (HAP) and communication system operating in the stratosphere to bring affordable, fast connectivity to every corner of the world. A single HAP will provide coverage over an area of up to 140 kilometres in diameter, equivalent to deploying hundreds of today’s terrestrial masts. A fleet of around 60 HAPs could blanket the whole of the United Kingdom with connectivity, providing even geographic coverage of peak 5G speeds in excess of 100 Gbps in aggregate. With radically cheaper costs, this new platform has the potential to connect the unconnected in the developing world, to fill gaps in coverage across the developed world and to ensure rural areas aren’t left behind anywhere across the globe. In addition, the hydrogen power system creates a long endurance, low environmental impact aircraft, with low noise, zero CO2 and zero NOx emissions.
As first announced on October 19 2020, SPL completed its first successful test trial during September 2020. Rollout of the first commercial service is anticipated to begin in Germany during 2024.
The companies suggested on a press call yesterday, that the U.K. will require another 400,000 masts to provide national 5G coverage. “This single mega cell tower in the stratosphere will provide coverage that is equal to the combined efforts of hundreds of terrestrial cellular masts, rewriting the economics of mobile broadband,” said Richard Deakin, chief executive at SPL.
Cambridge Consultants claims to have one of the world’s largest independent wireless development teams and this antenna is said to be amongst its crowning achievements. Sitting at one eighth of the intended full size, the proof of concept is a feat of engineering. It has overcome the key technical challenges within simulated flight conditions and proven its modular design can scale seamlessly. Advanced calibration across the four tiles of the prototype deliver beams with astonishing accuracy, maintaining laser-like performance during flight motion and paving the way for the huge 32-tile commercial array to now be developed. Have a look at the video announcing this so called “technology breakthrough.”
Each antenna produces 480 individual, steerable beams, creating patterns that can be ‘painted’ onto the ground to cover specific areas such as roads, railway lines or shipping lanes. The ability to produce hundreds of beams enables the antenna to reuse spectrum ensuring fast and even coverage across the entire covered area. A unique, wholly digital beamforming capability gives massive flexibility in how services are deployed, allowing in-flight reconfiguration to deliver services beyond the reach of conventional fixed terrestrial networks. This includes following mobile users, including trains and autonomous vehicles, and providing coverage exactly where required, for example ending at national borders.
A prototype has already been tested with Deutsche Telekom in southern Germany, according to SPL. Deutsche Telekom has not yet responded to a request from Enterprise IoT Insights for comment. The project raises a number of questions, not least about its viability, as well as about the interplay with existing terrestrial networks and deployment schedules, and whether the new system might be utilised as a shared neutral-host infrastructure.
There is also a question about its likely usage, whether for consumer 5G connectivity or, more likely, for consumer in-fill coverage, plus as a vehicle for massive machine-type communications (mMTC), and redundancy, in general. But the innovation looks considerable, with its authors calling the whole thing, even in proof-mode, a “remarkable technical achievement.”
The antenna is designed to be powerful and low-energy, at the same time, as well as both huge (three meters square) and lightweight (120kg). It will be the “world’s largest commercial airborne communications antenna”, when it finally launches in 2024, said UK-based Cambridge Consultants, acquired by Capgemini in April. The firm called the prototype, even at one eighth of the intended size of the commercial model, one of its “crowning achievements.”
The consultancy said in their press release:
Advanced calibration across the four tiles of the prototype deliver beams with astonishing accuracy, maintaining laser-like performance during flight motion and paving the way for the huge 32-tile commercial array to now be developed. Each antenna produces 480 individual, steerable beams, creating patterns that can be ‘painted’ onto the ground to cover specific areas such as roads, railway lines or shipping lanes.
The ability to produce hundreds of beams enables the antenna to reuse spectrum ensuring fast and even coverage across the entire covered area. A unique, wholly digital beamforming capability gives massive flexibility in how services are deployed, allowing in-flight reconfiguration to deliver services beyond the reach of conventional fixed terrestrial networks. This includes following mobile users, including trains and autonomous vehicles, and providing coverage exactly where required, for example ending at national borders.
The hydrogen-powered aircraft, as the other piece of the innovation, is designed to fly at an altitude of 20,000 metres for around eight days, before coming down for refueling. It offers a low environmental impact, said SPL, with low noise, zero CO2 and zero NOx emissions.
A single HAP will provide coverage over an area of up to 140 kilometres in diameter – “equivalent to hundreds of today’s terrestrial masts,” said SPL and Cambridge Consultants in a statement. A fleet of around 60 HAPs over the UK would provide blanket 5G connectivity with peak 5G speeds in excess of 100 Gbps “in aggregate,” the pair said. This proposed flying-5G network will be a “fraction of the cost of building and maintaining terrestrial infrastructure,” they claimed.
“With radically cheaper costs, this new platform has the potential to connect the unconnected in the developing world, to fill gaps in coverage across the developed world and to ensure rural areas aren’t left behind anywhere across the globe.”
SPL’s Deakins added: “This unique antenna is at the heart of SPL’s stratospheric communications system. It was essential that we overcame significant technical challenges in the design of the antenna to enable us to deliver massive data rates in a unique environment where power was limited, where weight was critical and where cooling in the thin, stratospheric air was difficult.”
“The development and testing of the antenna has met or exceeded the design criteria and working with such a talented team at Cambridge Consultants has been one of the highlights of the program to date. We look forward to continuing the journey as we progress to the production-standard antenna,” he added.
Tim Fowler, chief sales officer at Cambridge Consultants commented: “Four years ago SPL approached Cambridge Consultants with an ambitious vision to revolutionize the telecoms experience by beaming connectivity from the sky. Our role, to design and build this ‘mega cell tower in the stratosphere’, has seen us make breakthrough after breakthrough and we’re excited to build on these innovations with SPL, on the path to commercial deployment.”
Cambridge Consultants became part of the Capgemini Group in April 2020. Capgemini recently announced its first set of Intelligent Industry offerings that leverage the Group’s pioneering capabilities in data, digital and industrial technologies. Focused on 5G and Edge, the new services will enable Communications Service Providers, Network Equipment Providers and Enterprises across industries to implement 5G and Edge technologies at scale.
References:
DT-backed 5G sky-network to launch – offering country-wide 5G with 60 masts, no rents
High Altitude Platform Stations (HAPS) — bringing connectivity to all