One solution to the digital divide here on Earth may actually be in the stars… or more accurately in orbit. Alongside approaches using Fixed Wireless Access (FWA), Low-Earth Orbit (LEO) satellites are poised to improve access to internet in rural areas in the coming years, but each has their strengths and drawbacks.
Addressing LEO Latency Concerns
The digital divide – the difference in access to knowledge, services, opportunity, and income based upon access to connectivity – isn’t going away any time soon, according to experts. A solution is needed which disrupts traditional cost models for network deployments, and GSMA Intelligence Principal Economist Kalvin Bahia alluded to this in a Mobile World Live webinar entitled “Advancing Toward a Connected World: The Role of Non-Terrestrial Innovations.”
“We forecast that by around 2025, while internet connectivity will still grow, we’re still forecasting that around 40% of the world’s population will be unconnected,” he said. “We’re going to need to see an acceleration in connectivity and mobile internet access if we’re going to achieve a number of international targets that have been set to connect the next half of the world to internet.”
In an interview with 6GWorld Jack Burton, Principal at consultancy Broadband Success Partners, said LEOs at the very least have potential in that regard.
“Universal coverage is the [hypothetical] big benefit [of LEOs]. There’s no specific ground-based infrastructure required other than at the customer’s home,” he said. He conceded that there may be additional latency, which is a sector-wide concern regarding the technology.
In fact, the Elon Musk-founded SpaceX recently applied to become the first LEO provider to benefit from the U.S. government’s Rural Digital Opportunity Fund, eventually winning $885 million in subsidies in the auction’s first phase. However, SpaceX’s Starlink satellite constellation first had to disprove the Federal Communications Commission (FCC)’s reported skepticism that it would meet the 100ms latency standard. Starlink reportedly came in under 20ms, which is consistent with ground-based broadband.
In principle, it wasn’t a surprise to Michele Zorzi of the University of Padova’s Department of Information Engineering.
“The main issue with satellite communications in terms of latency is that the time of travel from Earth to satellite and back may be very large and if the satellite is at 36,000 km [with geostationary satellites] that’s going to be an issue, but, if LEOs are at 300 km or 1,000 km, then it’s like going coast to coast in the United States,” said Zorzi in an interview alongside University of Padova colleague Marco Giordani.
Zorzi and Giordani spoke to 6GWorld about a recent paper of theirs entitled Non-Terrestrial Networks in the 6G Era: Challenges and Opportunities. Zorzi added that one potential drawback to LEOs is their high-mobility patterns. Even so, he explained, it’s being addressed.
“You can place a High-Altitude Platform in a given position and it stays there, whereas satellites inherently move unless they’re geostationary, but that’s very high altitude. LEO is closer to the Earth, but these will have to orbit, so they will have a high-mobility pattern,” he said. “So, a satellite would go away and then a new satellite would come in, but that’s actually a normal problem. LEO satellites are in existence, so people know how to handle this issue.”
The Benefits of Non-Terrestrial Networks
Giordani meanwhile elaborated on the lack of terrestrial infrastructure as a benefit. According to him, it’s not just a question of the infrastructure itself, but the terrain on which it would be deployed.
“This is very expensive, particularly […] in the rural areas because of the very difficult degrees of terrain that may be encountered,” he said. “At the same time, [Non-Terrestrial Networks] can provide 100% availability. So, they are very robust to external events like natural disasters or terrorist attacks […] Also, these elements can be deployed everywhere, above oceans, above deserts, in those areas where installation of terrestrial infrastructure is not even possible.”
FWA has been used to address rural coverage constraints in countries including the United Kingdom. One concern of FWA is a lack of range, especially over mmWave frequencies, although U.S. Cellular completed an extended range 5G mmWave data call over 3.1 miles recently. Burton was optimistic about the development, but still presented the inability of mmWaves to penetrate so much as walls as a challenge. In that sense, the terrain itself could present an issue, Zorzi said.
“You may provide 3.1 miles in visibility, but as soon as you have a rural environment with hills or geographical obstructions or rain that obstruct propagation then it becomes hard to provide that coverage over that distance,” he said.
“Of course, this problem is also there with satellites. You have trees, but at least from the point of view of hills or canyons, covering from above will not be blocked. In fact, I don’t know if what we’re talking about here is ‘either/or,’ if we’re to go for a purely Fixed Wireless Access solution or a pure satellite-based solution. Most likely, it’s going to be a combination so that each can leverage its own strengths.”
Achieving 100% Connectivity Won’t Be Easy
According to Ericsson, FWA investments have payback times of less than two years. In comparison, Sue Marek argued in her Fierce Wireless column that financial instability due to an unclear business model is holding back LEO companies. She cited OneWeb being rescued from bankruptcy as one example. She also made the point that Amazon, which is investing $10 billion in a satellite broadband plan called Project Kuiper, has more to gain than simply helping to bridge the digital divide, namely more retail customers.
According to Giordani, there are plenty more use cases to explore, though. For one example, satellites can simultaneously provide umbrella coverage to all required sensors for Internet of Things applications. For another, Zorzi said terrestrial installations can offload traffic to satellites to increase network capacity at times of high demand. While Intelsat, a satellite services firm, does not deal in LEOs, Director of Innovation and Strategy Ken Takagi nevertheless said all networks, both terrestrial and non-terrestrial in nature, will likely figure into the solution.
“When we discuss the issue of connecting the unconnected and connecting everyone in the world, we’re not going to get there with a single solution. So, it’s going to be a combination of different technologies, different platforms, different concepts,” he said, speaking at the previously mentioned Mobile World Live webinar.
“It’s going to be innovations from terrestrial networks and expansion of reach,” he continued, “There’s going to be different types of satellites, LEO, [Medium Earth Orbit; MEO], Geo that each bring their respective benefits and value to the table and… there’s probably going to be newer things that we have yet to identify.”
Feature image courtesy of SpaceX (via Pexels).