VHTS: Soaring to Unprecedented Heights

It wasn’t so long ago that we hailed the era of High Throughput Satellites (HTS), which made it possible to deliver high-speed broadband data through narrow spot beams — enabling spectrum to be used, and reused, more efficiently.

But as satcom enters the 2020s, the days of HTS systems with speeds of 100 Gbps are about to become as nostalgic as iPods.

With a new decade upon us, satellite manufacturers have their sights set on the next iteration of HTS —super-high-capacity satellites that can deliver up to one terabyte of data, and in doing so, support a wider breadth of consumer, commercial, and military applications. Frequently referred to as Very High Throughput Satellites (VHTS), the latest batch of post-HTS satellites are characterized by flexibility, power, and speeds of 200 Gbps and up that enable an optimal Internet experience to end users, over land, air, and sea.

“If you look at the Cisco VNI index and how much capacity is going to be consumed over the next 5 or 10 years, the story’s always the same,” says Dave Rehbehn, vice president of Hughes’ International Division, which is overseeing the production of an ultra-high density satellite named Jupiter 3 (designated EchoStar XXIV) slated for launch in 2021.

Hughes Network Systems, along with satellite manufacturers and service providers like Thales Alenia Space, Viasat, Inmarsat, Intelsat, and others, is one of a growing number of HTS developers with its sights set on higher and higher ambitions.

But with all of the commotion around VHTS, one has to wonder if the next generation of super powerful HTS can keep up with escalating demands.

Rising High

In the early 2000s, when engineers started developing the first HTS systems, many millennial consumers were still in grade school.

High throughput satellites built on the premise that high-capacity, geosynchronous satellites could efficiently re-use frequency in the Ka- and Ku-bands to deliver information over narrow bands to spot-beam antennas on Earth. In doing so, they made traditional wide-beam, fixed satellite service looks dated.

“The big idea there was, instead of taking your spectrum and distributing it on the Earth in very wide beams, you would take a lesson from the cellular industry and you would use very small beams, and reuse the frequency, the spectrum, in these really small beams,” says Rehbehn. “And that’s how, with HTS, we get much more capacity.”

When ViaSat-1 entered the marketplace in October 2011 as an HTS in the Ka band, with throughput rates of 140 Gbps, it was lauded for having more capacity than any other commercial geosynchronous satellites in the world, Dave Ryan, Viasat’s president of space and commercial networks, tells Via Satellite.

Next came ViaSat-2, which has capacity of around 260 Gbps, or nearly double the throughput of ViaSat-1. The company is currently working on ViaSat-3, a trio of ultra-high-capacity satellites which will deliver capacity over one terabit per second.

“Everybody’s got their own definitions of what’s high throughput versus what’s very high throughput,” says Ryan. “We’re pretty agnostic when it comes to being specific as to any particular kind of satellite or orbit. Our focus is ensuring there is enough usable and affordable bandwidth for whatever the mission.”

Fast forward to 2020, and we now have consumers in their 20s that expect to pay for, and receive, customized broadband content on multiple smartphones, digital watches, home assistants and more — demands that would have almost been unfathomable to their Gen-X parents. The February 2019 Cisco Visual Networking Index (VNI) projects that by 2022, we’ll have 5.7 billion mobile users accessing the internet on 12.3 billion mobile ready devices and connections.

As a result, we’re seeing two primary strategies starting to unfold, notes Lluc Palerm Serra, an analyst for NSR.

“Two approaches are applied to HTS procurements today,” says Serra. “There are satellite operators following very high throughput path — like Viasat or Hughes — [that] want to minimize that cost per gigabit per second via large scale satellites. They’re primarily focused on consumer broadband. The other strategy is to take a step-by-step approach to supply. Inmarsat GX, for instance, prefers to have smaller high throughput satellite with a lot of flexibility.”

That’s why the onset of VHTS, with its promise of vastly higher speeds and increased flexibility over traditional HTS, is coming at the right time.

“The business of satellite communications is changing from a business dominated by TV broadcasting to a business of broadband access and mobility,” says Xavier Lobao, head of future projects division in the directorate of telecommunication and integrated applications for the European Space Agency (ESA). “This requires large capacity. The goal is to grow the satellite capacity to one terabit per second.”

High Achievers

Thales Alenia Space, Europe’s largest satellite manufacturer, has seen a string of successful contracts for HTS and VHTS over the last three years, including HTS/VHTS contracts for Satria for PSN Indonesia and the Konnect VHTS satellite for Eutelsat.

At press time, Eutelsat planned to launch Thales’ Konnect VHTS, which features all-electric propulsion, in mid-January 2020 from the Guiana Space Center in Kourou, French Guiana. Over the next decade, the VHTS “will bring enough capacity to serve high speed Internet and in-flight connectivity markets at scale, offering fiber-like services both in terms of price and speed,” Eutelsat said in a statement.

The satellites’ “fully digital” VHTS architecture enables the manufacturer to offer a “meshed network” (VSAT to VSAT) from any set of beams to any other set of beams over several hundred spots — a capability that also supports private networks as well as wireless backhauling, according to Thales Alenia Space.

“The Thales Alenia Space solution is the first to benefit a fully digital repeater up to half a terrahertz of total bandwidth,” Pascal Homsy, Executive VP Telecommunications Thales Alenia Space, tells Via Satellite.

“With a classical four colors frequency reuse scheme,” he continues, “each frequency band is reused 50 times each 100 spots — 25 times on one polarization, 25 times on the orthogonal polarization. Thus, for a satellite offering 200 spots, the level of frequency reuse reaches two orders of magnitude, which is magnifying the total throughput by a factor 100 compared to conventional spacecrafts.”

Also, by offering greater digital flexibility, VHTS systems enable additional capacity when needed (so an operator can focus on regions at peak times), and the ability for an operator to deploy its ground segment progressively when there is enough demand (as with traditional terrestrial wireless networks).

High Expectations

From the perspective of satellite manufacturers, the biggest challenge in the new decade will be delivering the lowest cost per bps while maintaining the required quality of experience — a challenge in managing large capacity and spectrum reuse.

“Competition is in principle a good thing,” says Lobao. “The differentiation between competitors is going to be mainly on the management of their satellite system resources to obtain the lowest cost/bps while maintaining a good quality of experience.”

There are also financial tradeoffs to consider. While a large satellite with high capex is providing the lowest cost per bps, a provider actually needs to fill the large capacity with users to make the numbers work.

“While a smaller satellite costs less, it is less efficient in terms of cost/bps but is easier to fill or can be focused to a smaller target market,” says Lobao. “The technical challenges are to reuse as much as possible the spectrum, which is achieved through the many and narrower spot beams and the amount of capacity you can handle onboard the satellite, which is limited by power generation and dissipation and mass, associated to launch cost.”

Peter Hadinger, chief technical officer of Inmarsat, which was close to launching its fifth Global Xpress (GX5) VHTS at press time, says his company’s biggest challenge is meeting (and exceeding) consumer expectations.

“Consumers have become accustomed to continued improvements in speed and performance of their devices,” Hadinger tells Via Satellite. “From phones to televisions to internet, it remains imperative to meet these expectations while also keeping costs broadly flat. This is why the increased economies of satellites like GX5, and the additional seven satellites we plan to launch in the coming four years, are so critical. We have focused our cost efficiency work not only on the satellite but on the ground stations, networking and user terminals to ensure that Inmarsat’s global mobile broadband services remain a compelling offering. Of course, the other challenge is to ensure that our existing customers benefit from each new capability.”

Above and Beyond

Only four years since Hughes launched its Jupiter 2 HTS, which delivered significantly more capacity than a wide beam satellite, the organization believes it has positioned itself to better meet future internet needs. In developing its ultra-high density satellite expected to launch in 2021, which is being manufactured by Maxar’s SSL division, the company hopes to funnel 500 gigabits of broadband capacity across the Americas.

“HTS allows us to have a very good cost per bit and bring in the capacity we need to serve our subscribers,” says Rehbehn. “We use the term ‘ultra high density’ because, particularly in the United States, where we have a decent size business of over a million subscribers, when you look at where the subscribers are, it’s not just those who live in Montana, but also those in urban areas and ex-urban areas.”

And for third-world countries, where having even the most basic mobile broadband access is becoming more and more critical, VHTS may play an increasingly important role.

“In other parts of the world, like South America, there’s lower affordability for access, so many people do prepaid Wi-Fi,” says Rehbehn. “But even there, people buy access by the megabyte, and the apps automatically download, and max out their available data, so and we need better ways to control automatic downloads through satellite technology.”

Moving forward, Serra says he sees opportunities for satellite to continue growing and leveraging HTS and VHTS in 2020 and beyond.

“If you think about five years ago, 10 years ago, your data consumption was 10, maybe 100 times lower than today,” says Serra. “There are many places where fiber is not available, and people want to get connected. Apart from that organic growth of data consumption, satellite is growing the number of subscribers substantially, especially in rural areas. If you look at the addressable market for satellite in the U.S., it can be 10 to 20 million households. But today, it’s only about two million households that connect, so there’s a huge market opportunity.” VS