SPL demonstrates world first 5G connectivity from stratosphere

Cambridge-based Stratospheric Platforms has demonstrated five hours of 5G broadband connectivity between a ‘stratospheric 5G mast’ flying at 45,000 ft and a 5G smartphone.

The world first telecoms trial was run in collaboration with the Saudi Communications and Information Technology Commission (CITC) in the airspace above The Red Sea Project. Engineers connected to the local telecoms network, completing tests between a 5G base station, flying stratospheric antenna, and retail mobile devices.

The trial projected a 5G signal to an area of 450km²and proved the technology can achieve 90Mb/sec mobile download speeds comparable to terrestrial 5G networks at significantly lower cost.

The joint team established three-way video calls between the land-based test site, a mobile device operated from a boat and a control site located 950km away. Further land and heliborne tests demonstrated a user could stream 4K video to a mobile phone with an average latency of 1 millisecond above network speed. Signal strength trials, using a 5G enabled device moving at 100km/h, proved full interoperability with ground-based masts and a consistent ‘five bars’ in known white spots.

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“We see this as a significant breakthrough in the telecoms industry due to the future limitations of land-based masts,” Neal Unitt-Jones, commercial vice president Stratospheric Platforms Limited (SPL), told The Engineer via email. “As consumers demand faster mobile speeds – 6G and beyond – data transfer increases at the expense of wavelength, which will mean that the distance between domestic mobile masts is expected to reduce to ~500m. This technological limitation will affect rural and remote areas as well as local objection to multiple masts on every street.”

The trial was carried out in a Grob 520 carrying a 5G cell but the company will go to market with its own High Altitude Platform (HAP), a composite design with a wingspan similar to a 787 Dreamliner.

Unitt-Jones added that the remotely piloted aircraft will take off from commercial runways and will remain in the stratosphere for a week without needing to be refuelled.

“One Stratomast can replace 450 terrestrial mobile masts giving network operators huge savings in capital and operational expenditure,” he said.

The HAP will carry a large phased-array antenna designed for standard LTE/5G smartphones. SPL said the antenna enables virtually any shape of beam coverage to be “painted” on the ground and that 20kW of power for the antenna enables coverage equivalent to around 500 terrestrial masts.

First series aircraft will be propelled by hydrogen combustion engines provided by ‘a world leading aero engine partner’. The company added that it is working on fuel cells for its Series 2 aircraft.

SPL forecast commercial launch in 2025, with the company providing the tower and telecommunications companies providing customer services.