The capacity debate: Ku vs Ka band for inflight connectivity

Unless you are a regular inside the IFEC (in-flight entertainment and communication) world, then the abbreviations Ku and Ka won’t mean anything. However, if you are an industry insider, then the Ku vs. Ka debate is your own version of a television soap opera. Several years ago, we explained in detail what these abbreviations mean, as well as how they fit inside the global radio spectrum.

And in a nutshell, that really is all there is to it; Ku and Ka band are designators for specific parts of the radio spectrum:

  • The Ku band covers the radio frequencies from 11.7 to 14.5GHz.
  • The Ka band covers the radio frequencies of 26.5–40 GHz.

Both Ku and Ka are frequently used as marketing differentiators for selling in-flight connectivity products to airlines. The debate has often been quite controversial, comparable to the rivalry between Apple and Android users. Here at Gogo, we consider ourselves to be a technology agnostic company, so we’ve stayed away from the debate, focusing instead on picking whatever is best for our airline partners.

One of the best analogies for the Ku/Ka debate is the marketing blitz from mobile operators back in the early 2000’s in the US – as new players and post-merger companies entered the market, they often used their cellular technology in advertisements to their prospective customers. Terms like GPRS, EDGE, 4G and LTE were all over company marketing materials, regularly used as their unique selling points. In most cases, consumers did not know what the terms meant, but that didn’t stop the operators from using them as ways to lure new customers to their network.

The Ku vs Ka debate only becomes relevant when looking at factors other than frequency, using the metrics that should matter most to airlines:

  • Is there enough capacity to serve my passengers today and in the future?
  • Are there enough Ka band satellites covering all of my flight routes?
  • Can I ensure my passengers stay connected if something goes wrong?

Let’s start with capacity.  There is simply more capacity to serve aviation in Ku band, because today there are so many more Ku than Ka satellites.  This is particularly true over hub cities like Chicago, New York, London, Tokyo and other major areas of heavy aircraft concentration.  In these cities, it’s necessary to have redundancy of satellites and today we can and do use multiple Ku satellites for coverage over a single reguion.  In Ka, there’s generally a small fraction of one satellite available to serve those aircraft.

The fact is, Gogo has more capacity dedicated to serving aviation than any of the Ka satellite providers today and will have more capacity for the foreseeable future.  We have access to more than 50 Gbps of capacity today, we’ll up that to more than 100 Gbps in 2018 and we expect more than 10 Tbps in 2020 and beyond.  The Ka satellite providers share bandwidth with numerous other markets while Gogo dedicates capacity for the aero market. The only operator of Ka band satellite Internet serving aviation in the United States also serves an additional 675,000 residential customers.

In terms of coverage, the debate is also simple: Ku has a big coverage advantage over Ka for serving aviation.  There are 100’s of existing Ku band satellites in orbit covering the globe.  We cover more than 98% of global flight hours today with a high level of satellite redundancy. The maps above give (an approximation of) the number of satellites available to 2 of the leading Ka band operators and the Gogo Ku band satellite network.

There are two Ka satellite providers serving aviation and, unlike the Ku satellite system where you can leverage most of the satellites in orbit from the various providers, there is no interoperability between the two Ka providers.

Today, one Ka provider has three satellites in orbit providing near global coverage and will soon add a fourth; however, due to a few satellites covering the entire globe, capacity is spread throughout the globe almost uniformly and there simply isn’t enough capacity to serve any of the high air traffic corrridors.  The other Ka provider has one satellite in orbit covering different portions of N America (no global coverage), one about to launch adding coverage over the Atlantic and plans to add three satellites by 2020 for a total of five satellites.  Neither of these plans will match the 98% we achieve today and clearly will not have redundancy.  If the Ka providers try to allocate more capacity to hub cities, global coverage becomes even more problematic.  Simply put, four or five satellites is insufficient to provide high quality global coverage and to meet the capacity needs of hub cities for aviation.

As we mentioned before, Gogo is technology agnostic.  We are interested in providing whatever technologies will better serve aviation.  When you look at the relevant factors between Ku and Ka satellite service for aviation, it’s clear that Ku is the answer.

In fact, for Gogo, it’s not even close and we don’t see that changing anytime soon as new satellites with enhanced Ku band coverage are still being launched. A good example of this is the Intelsat Epic fleet of High Throughput Satellites that we recently used for our media/investor demo day. During this demo, we connected to the Intelsat IS-32e HTS satellite, and showed off what could be the fastest speed ever tested during a passenger flight.  Another HTS satellite, SES-15, which launched this month, provides additional capacity and redundancy for Gogo’s airline partners over North America.

Should there be a point in time that the Ka ecosystem provides a better option to serve aviation, Gogo will not only adopt it, we will provide our airline partners any easy upgrade path to leverage it.