When governments and consumers talk about wanting coverage and connectivity wherever they happen to be, simultaneously it’s a simple concept and a hard economic problem. With enough money it’s possible to build a country-wide Wi-Fi network indoor and out, but in practice nobody can do that. In the same way, while telecoms providers have for years aimed to provide certain degrees of population coverage, it has tended to focus on the areas where there are already densely packed groups of potential customers, for good the reason; the investment per customer is much lower.

Cue the role of satellites; to deliver coverage on a macro scale; to enable backhaul without expensive fibre builds, and so on. Until recently, the satellite communications industry fundamentally has been an in-fill solution where terrestrial telecoms can’t afford to invest or physically can’t reach. All this is changing, according to Vikas Grover, CTO at satellite operator Avanti Communications.

Structural Shifts

“The industry’s transformation started five years ago with the emergence of multilayer and LEO (low earth orbit) satellite technology and, more recently, smaller satellites and more frequent, more affordable launches,” he noted.

“Large-scale constellations have become possible… and the traditional manufacturing lead time is shrinking. This transformation, and the publicity around companies such as SpaceX, Starlink and OneWeb, has driven a change in people’s mindsets.”

Strikingly, that change in manufacturing and launch costs is starting to make itself felt commercially. While Grover noted that “the affordability of space broadband connectivity has been an Achilles heel for the satellite industry,” those prices are dropping significantly.

It’s also lowering barriers to entry for the sector. Avanti’s main focus has been on providing coverage across Africa. Now, though, it’s not just the likes of Amazon that can afford to send up satellites. “We see keen interest from several African governments, from building their satellites to public-private partnerships for satellite services leverage,” he observed. Particularly as there are large rural areas within many African countries where fibre infrastructure is not extensively built out, this move by governments to secure a backbone in space is sensible but also sets the scene for a very different kind of telecoms environment from what we see in Europe or Asia-Pacific.

Alongside that, Grover sees HAPS [High Altitude Platform Solutions] as a part of the region’s solution in the coming decade, as a means to improve capacity where needed. “We expect the HAPS introduction to follow a similar trajectory of 5-10 years for mainstream adoption,” he said.

He also pointed to Google’s Project Loon as providing an opportunity to accelerate the work of HAPS developers, despite its unfortunate fate. “Getting it right was a real challenge, as so many factors came into play, from ensuring the balloons could withstand wind and weather patterns,” Grover noted, “But the release of the Loon Collection has allowed others to follow in its footsteps. Some of Loon’s technology now lives on in Project Taara, very high-bandwidth free space optical communication technology (first leveraged in the Loon project for inter-balloon connectivity). Loon also transferred several stratospheric ballooning and networking patents to partners in similar fields to support ongoing innovation.”

Will Avanti be investing in its own HAPS system? Grover is tight-lipped. “We combine Avanti assets, our partner technology assets, and services from like-minded service providers across the spectrum,” he commented.

There is talk about 6G requiring a full integration between satellite and terrestrial network architectures to allow seamless interoperability for a properly ubiquitous service experience. How feasible is this, 6GWorld wondered?

“Integrating satellite and terrestrial networks is critical for developing 6G,” Grover stated.

“However, we are already seeing steps toward integrating satellite and terrestrial networks. Many satellite operators are partnering with terrestrial network providers to offer hybrid networks that combine the coverage and resilience of satellite networks with the low latency and high capacity of terrestrial networks.”

That said, it’s far from a done deal to Grover.

“While the concept of integrated satellite-terrestrial networks is not new, the scale and complexity of 6G will require a new level of collaboration and coordination between different stakeholders,” he commented.

“There are many challenges from a technical standpoint. For example, differences in transmission protocols, frequency bands, and network architectures when integrating satellite and terrestrial networks – we need to make sure the two aren’t interfering with one another!”

Spectrum High Jinks

Spectrum and interference are always contentious, and perhaps more so recently given the spat about 5G interference with aviation in the USA. In the run-up to WRC-23 later this year, 6GWorld couldn’t resist asking about competition… but also collaboration between satellite and mobile.

“Partner telecom operators often pursue spectrum sharing through either combined network rollouts or roaming on each other networks. Similarly, the satellite industry has always leveraged spectrum sharing through coordination agreements. In the recent past, the C-Band spectrum for United States terrestrial use was vacated by a group of satellite operators with US interests,” Grover pointed out.

If that’s a good example of collaboration on spectrum, there is another emerging area which might be a little less straightforward – direct-to-mobile communications from satellites, particularly LEO.

“Intriguingly, for this to work, the satellite operators would need to radiate the mobile operator spectrum from space.”

Not impossible, but Grover greets it with caution. “Satellites use various frequency bands for multiple applications, including communications, remote sensing, and navigation. Spectrum sharing can improve the use of spectrum resources, particularly in frequency bands where demand is high and supply is limited. However, satellite operators have raised concerns about the impact of spectrum sharing on their services and the potential for interference.”

Overall, a possibility but it would demand “close coordination between ITU, local governments, regulators, and telecom operators.” Something of an understatement. Use of mobile spectrum from satellite would be problematic for managing interference, such as power limits, antenna beam steering and frequency separation.

“Another challenge is the need for clear regulatory frameworks and agreements to ensure fair spectrum access and avoid user conflicts,” Grover pointed out.

Far from current spectrum, China tested the use of THz spectrum in space for satellite-to-satellite communication. Given the problems with propagating THz spectrum limiting its use on the ground, what does Grover think of the idea of it being effectively an out-of-atmosphere solution?

“It offers some potential benefits over traditional microwave frequencies,” Grover admitted.

“These frequencies have much higher bandwidths, supporting high data rates, making them suitable for high-resolution imaging, remote sensing, and scientific missions. Another advantage is that they are less affected by atmospheric absorption, which can reduce signal strength and quality.”

Grover pointed out that inter-satellite links [ISLs] of any kind aren’t yet mainstream, though suggested a timeframe of 3-5 years would be credible, at which point they could, potentially, complement undersea cables as a means to provide backbone connectivity over long distances.

“THz or optical spectrum for inter-satellite communications can change how we connect. However, several technical and operational challenges need to be addressed, and further research is required to explore these approaches’ feasibility and practicality,” he commented.

Overall it looks as though there’s a rival and a complement to traditional terrestrial network infrastructure waiting in the wings – from the backbone to the radio. While countries with extensive existing infrastructure may find this useful for in-fill, it could be transformational for nations with little infrastructure or extensive rural areas. It would offer the chance for knowledge-economy workers to live anywhere, aiding in a rebalancing of populations to the countryside in some areas.

In some areas the impact would be much more profound, as Grover points out: “Yes, the direct-to handset is on the horizon, and many people want the ability to use their mobile devices where there is little or no cellular coverage, but approximately 37% of the world’s population – 2.9 billion people – have still never used the Internet.”

That third of the population has already, in large part, been covered by satellite services; but the changes in capability and price taking place over the coming decade will put those services much more comfortably within reach of end users. For that third of the population, access to information, education and services will be huge. During the rollout of 4G the GSMA used to highlight that a 10% improvement in access to mobile resulted in a 1% growth in GDP. What they will make of access to communications, information, AI and much more we can only speculate about.

Note – To hear more on this and related topics, 6GWorld will be hosting a webinar “Mind the (Digital) Gap: How Satellites and 6G Can Help Connect People” May 7th. Register for free here.