Cambridge triple role in superfast 5G project

The collaboration between the Cambridge companies along with BT Group and Britten-Norman won the Information, Data & Connectivity Award at The Engineer UK Collaborate 2 Innovate Awards.

The technology at the heart of the solution will bridge connectivity gaps by eliminating white spots and aid emergency response, rural communications, and large-scale events, Cambridge Consultants reveals in a case study.

The Science Park business discloses that at the heart of the innovation is its modular phased-array telecoms antenna. Designed to be scalable, the modular nature of the antenna means that smaller, highly capable arrays can be tested before reaching full commercial deployment.

SPL collaborated with Cambridge Consultants and BT to successfully trial these subscale arrays at BT’s R & D headquarters at Adastral Park, Suffolk. Cambridge Consultants says this marked a significant milestone, proving the viability of the technology on the ground.

It says in a web-based case study: “This is a story of a radical breakthrough. It reveals our part in a highly ambitious plan to deliver superfast 5G to every corner of the globe from the stratosphere.

“Working with Stratospheric Platforms Limited (SPL), we’ve developed an airborne antenna that will provide widescale coverage of high performance 5G at a fraction of the cost of terrestrial networks.

ªThe full-scale antenna will take flight at three meters square and deliver quite extraordinary mobile broadband speeds – beaming high performance 5G over vast geographies and to exceptionally targeted areas from an altitude of 20,000 metres.

“Yet it will be light enough to be carried by a zero-emission aircraft weighing no more than a medium-sized van. It sits proudly at the heart of SPL’s revolutionary high-altitude platform (HAP) and communication system.”

SPL’s vision is to use the stratosphere to rewrite the economics of mobile broadband and connect everyone with the fastest 5G speeds possible, which until now have been the reserve of major cities, Cambridge Consultants reports.

In partnership with Deutsche Telekom – its largest shareholder, technology partner and launch customer – SPL plans to launch a fleet of unmanned, zero-emission aircraft to deliver 5G into existing networks and directly to standard phones, the company adds. The aircraft will use a unique hydrogen power system to increase endurance, whilst reducing environmental impact and noise.

A number of world firsts shine through the project. Central to SPL’s vision was the need for a unprecedented telecoms payload that could be carried by an aircraft weighing about 150 times less than a Boeing 747, overcome the stratosphere’s atmospheric challenges and endure nine days of flight.

Due to its size and performance, the antenna would do the serious work of providing exceptional 5G services over vast geographical distances, delivering airborne communications unlike anything seen before.

The world’s largest antenna of its kind is at the heart of the ingenuity, Cambridge Consultants reveals.

“Our ground-breaking proof of concept has made possible what was once unthinkable,” the firm says. “When developed, the full-scale antenna will be over three metres square, include more than a million components, create 480 individual beams and provide even coverage of high performance 5G to areas up to 140km in diameter.

“This single ‘mega cell tower in the stratosphere’ will deliver mobile speeds in excess of 100Gbps in aggregate and provide coverage that is equal to the combined efforts of hundreds of terrestrial cellular masts.”

At one eighth of the intended full-size, the fully functional proof of concept is a feat of engineering, the company adds. It has overcome the key technical challenges within simulated flight conditions and proven its unique modular design can scale seamlessly.

Advanced calibration across the four tiles of the prototype deliver beams with what Cambridge Consultants calls “astonishing accuracy, maintaining laser-like performance during flight motion and paving the way for the 32-tile commercial array to now be developed.”

It adds that projecting cells from the sky enables service providers to dynamically change location and power allocation to meet changing end-user demands.

“Experimenting with this freedom, we found that a Fibonacci spiral – a pattern seen in mathematics and nature – improved aggregate traffic performance by 15 per cent compared to conventional hexagons, achieved by reusing spectrum in a much greater way than Massive MIMO,” the company reports.

Wholly digital beamforming on this massive scale is a novel concept, as the company points out in the case study. “It means the antenna can segment the ground into small enough cells to create precision patterns that cover specific areas such as remote villages, roads and railways.

“This enables service providers to create highly targeted cellular services that track users, like individual trains or vehicles.”

Dissipating heat with an airflow equivalent to the gentlest of human breaths on a low drag aircraft was a challenge like no other. Cambridge Consultants reports. “A ground-breaking cooling system was invented to duct air evenly across the array, whilst providing direct air cooling to high surface area, low mass heatsinks with minimum airflow.

“Making the antenna light weight and super thin, whilst maintaining performance, was critical to enable an aircraft weighing just 3.5 tonnes to endure flight for over a week at a time.

“Weighing in at just 120kg, the full-scale antenna will enable SPL’s aircrafts to easily create lift in the exceptionally thin air of the stratosphere where the atmosphere is just 10 per cent of that at sea level,” the case study adds.

Richard Deakin, CEO of Stratospheric Platforms Limited, has been mightily impressed. He is quoted as saying: “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 programme to date.”

Cambridge Consultants adds: “We have been working alongside SPL to solve a global challenge: most populations experience scattered access, or no access at all, to fast cellular speeds.

“SPL estimates their HAP system presents global market opportunities to connect and upgrade over 500 million people with exceptional mobile broadband, filling gaps in coverage and opening opportunities for new industrial 5G use cases, like eHealth and machine remote control.”

SPL has also taken a huge step in disaster relief and emergency communications by developing a cutting-edge airborne 5G/LTE platform.

Recognising the catastrophic impact of the “simultaneous loss of all fixed and mobile communication”, whether due to natural disasters, infrastructure failures or cyber threats, the company has modified a Britten-Norman (B-N) Islander aircraft to serve as a technology demonstrator for airborne 5G/LTE direct-to-device (D2D) communications.

The pioneering system delivers high-speed, broadband-equivalent connectivity without reliance on traditional mobile towers or fibre networks, providing critical voice, video and data services at speeds of up to 220Mbps.