In inflight connectivity, the big technical debate has moved from the type of band used — Ka-band vs Ku-band — to optimising networks around geosynchronous earth orbit or low earth orbit satellites, or GEO and LEO, respectively. We delve into the issues with the help of Reza Rasoulian, vice president at Hughes Network Systems, which recently added OneWeb’s LEO network to its JUPITER GEO network portfolio via a new distribution partnership.
In the aviation context, the primary consideration today when it comes to the question of GEO vs LEO is one of capacity (largely expressed as speed in gigabits or megabits per second) versus latency (largely expressed as the time delay between a request and its answer).
Deeper within aviation, and acknowledging that this is a simplification, where GEO coverage exists it is likely to be higher capacity and higher latency. LEO networks, meanwhile, are usually the reverse: low latency, but lower capacity as well.
To further simplify in real terms: GEO satellites might be better overall when it comes to purposes like streaming a movie because users want more bandwidth, but it feels less responsive because the question-answer process to the ground has to travel over 70,000km, or nearly 45,000 miles, from aircraft to satellite to ground station and back again. LEO satellites orbit much lower (OneWeb’s are at some 1,200km or 750 miles) and might be better overall for use cases that require a fast response — scrolling video like Instagram Stories or TikTok, for example. Other use cases, like sending emails, perform reasonably well via either technology.
A third factor, and one that is a spoiler in some cases, is the question of coverage. GEO satellites are larger, designed to permanently cover a specific geographic area, generally resulting in strong performance where they exist. LEO satellites, meanwhile, are smaller, designed for global coverage at full network deployment, meaning that adding specific capacity in key demand zones is more complicated.
Today, Hughes’ Rasoulian tells us, “there are solutions that are that are being positioned in the marketplace that are GEO or LEO. This is a really important distinction, because those antennas are either talking to a GEO satellite, or a LEO satellite.”
Indeed, Hughes itself offers these as separate options, with its JUPITER In-Flight service offering GEO service over Ka-band to the aircraft and its LEO In-Flight service offering LEO service over Ku-band to the aircraft.
But its new option is Hughes Fusion In-Flight, leveraging a packet-level traffic splitting technology which offers both Ku-band LEO and Ka-band GEO — or, indeed, GEO service from any provider, since that element of Fusion is band- and service-agnostic.
“Within the Hughes Fusion technology,” Rasoulian says, “for both of the radios — the GEO up and down, forward and return, and the LEO up and down, forward and return — our Fusion software can actually use both links simultaneously within the same session.”
Crucially, he explains, this isn’t cost-based or smart routing, but rather detecting latency-sensitive packets and routing those over LEO, with non-latency-sensitive packets or those requiring higher data flow routed over GEO.
This is helpful, Rasoulian explains, in that “we basically have two radios on the aircraft, one that’s focused on GEO, and another that’s focused on LEO. So, it’s effectively a no-compromise solution, where we’re leveraging the benefits of GEO, which is high density — if you look at GEO Ka band, we have tens of gigabits over New York, for example, or the Greater Chicago area, Greater Dallas area. We have anywhere from 30 to 50, 60 gigabits per second, so a lot of capacity.”
Adding flexibility in this way, or in others, also serves as contingency — both technical and commercial — which will be at the back of minds (if not indeed the front) after 2023’s Inmarsat I-4 F1 outage and ViaSat-3 Americas deployment anomaly, as well as Viasat’s acquisition this year of competitor Inmarsat. At a time of rapid industry change, this sort of contingency is, in and of itself, valuable.
Published: 05 September 2023
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