SmartSky and Cambridge Consultants discuss adapting cellular technology for aviation air-to-ground private networks
According to SmartSky CTO Dave Claassen, the biggest challenge of providing inflight air-to-ground (ATG) connectivity is that unlike a regular cellular network, ATG must operate in “three dimensions.”
“You have to take off … achieve altitude, then you have to blaze across the country… and then obviously, you have to land,” he said; and all the while, the aim is to deliver a seamless broadband experience for cabin and crew. At the Private Networks Global Forum, Claassen joined Colin Campbell, SVP of wireless and digital services at Cambridge Consultants, to detail how the two companies customized existing cellular technology to solve the challenges this presented in order to deliver a novel aviation network.
While different in some ways from a typical cellular network, Campbell pointed out that the economies of scale present in cellular technologies are still relevant in this context, as well as technical features such as mobility, initial signal acquisition, site-to-site hand-off, etc. “All of the normal things we’re used to experiencing on the ground using our mobile phones,” he summarized. But in this case, they are being adapted to a network connecting an aircraft that’s flying at 40,000 feet at 500 miles per hour.
“The real challenge underpinning all of that is adapting the technology in the first place,” Campbell continued. “There’s a bunch of features … you don’t want to lose … and you want to add this subset of features without destroying that base … It’s completely different from a blank sheet of paper where you have complete freedom to do almost whatever you want.”
Beamforming, for example, proved particularly useful when it came to solving the issue of range, or of getting the signal to the aircraft once in the air. Beamforming techniques essentially shape radio waves through adjustments to phase and amplitude to make them more powerful and targeted. So instead of blasting coverage out throughout a cell, beamforming can direct coverage where it’s needed.
“For a simple point-to-point network, [beamforming] is trivial to do,” claimed Campbell, “But to make sure that it works seamlessly so that the user on the plane has no idea that you’re switching between beams … without breaking that basic functionality, was really hard to do.”
According to Claassen, it was beamforming — and performing the handoff between the beams seamlessly — that “got enough energy into the aircraft” so that users can have the same bandwidth experience in that air as they do on the ground.
“It’s an example of … making key changes without really impacting the underlying system and that’s what you have to do when you look at customizing technology… the benefits that you get from using existing technologies are great if you can adapt them successfully,” concluded Campbell.
