This article originally appeared in the Aug. 27, 2018 issue of SpaceNews magazine.
As governments, companies and everyone in between prepare to trade out 4G wireless infrastructure for 5G, questions linger about what the transition will entail. For satellite communications companies, this switchover could be more daunting than any previous cellular transition.
The performance benchmarks for 5G wireless service are high: user download speeds of 100 megabits per second (Mbps) and uploads of 50 Mbps with a millisecond of maximum signal lag. That’s five times faster than the average household internet connection in the United States and Europe and 15 times faster than the global average. And all of this needs to be done with three times the spectral efficiency of 4G, effectively tripling the volume of data that can be sent over the same amount of spectrum.
Satellites today are just starting to near those throughput markers — Viasat’s ViaSat-2 offers 100 Mbps download speeds and Eutelsat and Hughes are building similarly capable satellites — but none are close to a single millisecond of latency.
Fifth-generation networks also must be capable of supporting a million devices in a single square kilometer and maintain connections for mobile devices traveling up to 500 kilometers per hour.
Despite these challenges, satellite operators, analysts and industry observers remain optimistic that space-based communications will play a significant role in connecting 5G devices. SpaceNews spoke to experts in the U.S. and Europe about what the satellite industry needs to know about 5G.
1. When will 5G networks start activating?
An estimated 12 percent of cellular operators say they will start commercial 5G service this year, according to an August study by IHS Markit. The bulk of 5G rollouts are expected in the subsequent years, however.
“The U.S., China, South Korea and Japan — these four countries are in the front,” said Emanuel Kolta, an 5G analyst at ABI Research in London.
Kolta expects those four early adopters to lead the way into 2019, followed by Western Europe and Australia.
“It is going to get more and more common, and we can see an inflection point: at 2020, it is going to get more common globally,” he said.
Thierry Lefort, who leads European satellite business for the telecom, media and technology practice at PwC’s Strategy& division, said a recent poll of mobile network operators found few are rushing to implement 5G.
“A lot of players are engaged in trials, but the actual deployments will start very slowly,” Lefort said from Amsterdam. “This is what we believe. Many operators mentioned to us that they will not start before 2020 or 2021, and it is likely to be in some areas a slow start.”
2. Is satcom being considered as 5G networks are defined?
The answer is yes, says Nelson Malaguti, at the Geneva-based International Telecommunication Union’s Radicommunication Bureau. Compared to previous technology generations, 5G is “a network of networks or system or systems,” he said, and that higher level of interconnectedness means factoring in all kinds of telecom infrastructure.
“The previous ones were focused on terrestrial systems — 3G and 4G — but now this concept of integration is really in place,” he said.
“The good news is that satellite has been included into 5G standards, and now can become an integral part of 5G,” said Lefort, referencing the work of a coalition of seven telecom standards organizations called 3GPP — the 3rd Generation Partnership Project. “That is basically the start of the conversation: to recognize there is an opportunity because satellite has been included into 5G standards.”
3. Will 5G’s one-millisecond latency benchmark doom satellite applications?
A lot of the time, yes, but not always. Malaguti said the ITU originally sought to put a number on how much 5G traffic will go over satellite, at one point projecting around 20 percent, but ditched that figure.
“It depends, because not all applications are latency sensitive,” he said. “You have some applications like video where if you want to transmit something you can store and cache it. This is not latency sensitive. Not everything needs one millisecond.”
Kolta said the significance of latency is “one of the most relevant questions for 5G in satellite.”
“In general, satellites naturally have longer latency than terrestrial systems and this is one of the key disadvantages of satellite for 5G,” he said.
Self-driving cars, for example, will need extremely low latency, while a moisture sensor at a farm may only need to phone home once an hour.
Orbiting 36,000 kilometers above the Earth, geostationary satellites generally have an unavoidable signal lag between 500 and 700 milliseconds — a far cry from the goal of 5G — but satellites in lower orbits get closer to the mark. SES’s O3b satellites, operating in medium Earth orbit at 8,000 kilometers, have less than 200 milliseconds of latency. Future low Earth orbit systems like those of SpaceX, OneWeb and Telesat target 50 milliseconds or less.
“If you consider these three types of constellations, GEO, MEO and LEO, you can cover a lot of applications, even some latency sensitive applications,” Malaguti said.
4. What will satellite be used for in a 5G world?
One of the main differences between 4G and 5G is that the latter will need many more base stations to cover the same geographic area. Lefort estimated three to five times as many base stations — be they connected to towers, buildings or lamp posts — will be needed to cover an area with the amount of capacity and speed demanded.
Here the ability of satellites to single handedly cover entire continents comes in handy.
“You start with the advantages that satellite has, like ubiquitous coverage,” said Tom Stroup, president of the Washington-based Satellite Industry Association.
Satellites can bring 5G to areas where terrestrial connectivity companies consider it too expensive to build fiber-optic cables. Rural areas especially stand to benefit from satellite connectivity, Stroup said.
Stroup said he found himself during a recent visit to sparsely populated South Dakota without 4G or even 3G connectivity.
“There are ranchers and farmers in that area that would desire existing broadband or mobile service and it’s not there today,” he said. “That’s why I say it’s hard to envision that 5G is going to create a business model that is going to put small cells on every fence post in areas like that.”
Satellites can link central 5G stations to small cell stations in rural communities, Malaguti said, a service known as trunking. Satellites can also “backhaul” connections directly to local cell stations for extremely remote locations like islands, he added.
“The possibility for satellite 5G is to cover areas that will not be covered by terrestrial 5G,” said Lefort. “Inherently, terrestrial 5G will never be able to reach the coverage of 4G in the next five, perhaps even 10 years, as it requires densification of the radio network — base stations — which will be achieved mainly via small cells.”
Airplanes, trains boats and other vehicles that frequent regions of the planet beyond the reach of cellular companies will continue to rely on satellite links, experts agreed.
5. Will 5G’s spectrum needs harm the satellite industry, or help it?
New frequency bands for 5G “may be the hottest topic of WRC-19,” according to Malaguti. He said ITU is finalizing a document called the Conference Preparatory Meeting report that will contain all the studies performed ahead of the 2019 World Radiocommunication Conference where regulators decide on how to allocate spectrum around the world.
While much of the focus in the U.S. is on C-band where Intelsat, SES and Eutelsat have agreed to cede some of the prized spectrum for 5G in exchange for financial compensation, experts said most of the discussion around 5G spectrum globally is on other frequencies.
Malaguti said the majority of spectrum conversations are about “much higher frequency bands,” within the 24.25 to 86 GHz range, many of which are not heavily used by satellites.
“Satcom operators have been proactive in stating which higher bands they would not care so much about,” Lefort said. “There is not as much at stake in those un-chartered higher bands. There have been a lot of proactive discussions, including with 5G players very influential toward the ITU like Qualcomm and others.”
Lefort said that while more amicable discussions — if there is such a thing for spectrum — are happening around higher bands, it is true that lower frequencies like C-band are easier for cellular operators to work with.
“If you are a 5G telecom operator the first thing you want to do is deploy in the lower bands, for economic reasons, until the business case is demonstrated for higher bands,” he said.
Malaguti said spectrum sharing — an idea decried in the satellite industry — could be possible on a limited basis in regions where satellite terminals are not heavily employed. Such a compromise would be a difficult sell, but Malaguti says he is “always optimistic.”
“We can make studies and come to some detailed conclusions allowing the shared use of the bands, or where it is not possible to share we can find a balance to allocate these bands,” he said.
Stroup said it’s possible satellite operators could even gain some spectrum as discussions around 5G progress.
“As we start deploying the services, there will be an ongoing evaluation of what spectrum is needed, so I think there may very well be an opportunity.”