Inside the Lab: Expanding connectivity by sea, land, and air

By Dan Rabinovitsj
October 7, 2021

Since 2013, Facebook Connectivity, together with our partners, has accelerated people's access to a faster internet around the world. Currently, over 300M people have benefited from better infrastructure, network analytics, or access technologies. We have accomplished this thanks to strong partnerships and innovative technologies, such as: 

  1. Our first-ever transatlantic, 24-fiber-pair subsea cable system will connect Europe to the United States. This new cable will provide 200 times more capacity than the transatlantic cables of the 2000s and builds on our recent news about 2Africa Pearls, the subsea cable connecting Africa, Asia, and Europe, and that will make the 2Africa cable system the longest in the world, and will provide connectivity for up to 3 billion people.  
  2. We are making fiber deployment significantly more economical through Bombyx, a robot that can climb medium-voltage power lines, which exist in so much of the world, and install fiber onto them. Today, Bombyx is lighter, faster, and more agile than our first-generation design. We are also making Bombyx fully autonomous, using machine vision sensors to help it better navigate around obstacles.
  3. Terragraph, a wireless solution that beams multi-gigabit connectivity through the air, has already brought high-speed internet to more than 6,500 homes in Anchorage, Alaska, and deployment has started in Perth, Australia. We license Terragraph for free to original equipment manufacturers (OEMs). To date, these partners have shipped more than 30,000 Terragraph units to more than 100 service providers and system integrators around the world. 

Our use of the internet for work, education, health care, and social connection continues to increase, with data consumption per person growing 20 percent to 30 percent annually. And despite this rapid growth, nearly half of the world is being left behind, either lacking adequate access to the internet or going completely unconnected. 

To bring more people online to a faster, more reliable internet, Facebook Connectivity works with partners to develop new technologies for access to high-speed internet. Today, we’re sharing the latest developments on a few of these connectivity technologies, which aim to deliver major improvements in internet capacity across the world by sea, land, and air.

“We have seen that economies flourish when there is widely accessible internet for individuals and businesses,” says Cynthia Perrett, Facebook’s Fiber Program manager. In Nigeria, for instance, increased broadband connectivity resulted in a 7.8 percent increase in the likelihood of employment for people in areas connected to fiber optic cables. This means that for every 1 million people living in areas connected to fiber, an additional 78,000 people became employed. Or consider the Democratic Republic of Congo, where increased connectivity led to a 19 percent increase in GDP per capita ($789 vs. $663 at purchasing power parity).

Subsea cables lay the foundation for the global internet connecting continents, and as we build more than 150,000 kilometers of them with our partners, we’re also working on new technologies that will enable floating, solar-powered buoys in the middle of the ocean to help these cables carry much greater volumes of data.

While subsea cables are part of the foundation of the global internet, once a subsea cable reaches shore, the next step is to deliver bandwidth to communities. On land, we have developed Bombyx, a robot that has the potential to dramatically reduce the cost of rolling out fiber-optic cables to communities by moving autonomously along power lines and wrapping them with cable. And for dense urban areas and environments that hinder fiber rollout, we’ve built Terragraph, a wireless technology that beams gigabit-speed internet through the air to connect homes and businesses.

“Through our connectivity efforts, we’ve helped accelerate more than 300 million people’s access to a faster internet, and we look forward to enabling affordable high-quality connectivity for the next billion,” says Dan Rabinovitsj, VP of Facebook Connectivity. 

Today, we’re sharing the latest on these innovative connectivity technologies being developed inside our labs.

Subsea cables: Building infrastructure through innovation 

When we use our phones, computers, or VR headsets to connect to someone we care about or to find information we need, we often forget about the technology that makes it all possible. Fiber-optic cables are one of the best ways for delivering affordable high-speed internet because they carry more than a thousand times the bandwidth of other communications technologies. While fiber has huge potential for improving connectivity, more than 70 percent of the world still lives over 10 kilometers away from fiber as of 2019. This is partly due to some very difficult challenges that most people aren’t aware of but would have a huge impact if solved. These challenges include rough terrain, such as mountains and deserts; high costs for operators to build fiber in rural, sparsely populated areas; and lack of affordable materials that can stand up to rough weather conditions, ranging from high winds to desert heat.  

For this reason, we continue to invest in improving subsea fiber-optic cables and expanding their reach so we can better connect more people. For example, until recently, transoceanic subsea cables were composed of just two to eight fiber pairs. We have partnered with various industry players to push those boundaries, and today we are thrilled to announce the first-ever transatlantic, 24-fiber-pair subsea cable system that will connect Europe and the United States with a capacity of half a petabit per second — that’s half a million gigabits! To put that in perspective, that’s 200 times the capacity of the transatlantic cables built in the early 2000s.

This new cable system builds on our recent news about 2Africa Pearls, the subsea cable that connects Africa, Asia, and Europe, and makes the 2Africa cable system the longest in the world, helping connect up to 3 billion people.  

2Africa triples the total network capacity of subsea cables serving Africa, Asia, and Europe.

While we take a global perspective, we are also focused on incremental innovations. For instance, portions of the 2Africa project will use a new aluminum conductor system, replacing traditional copper conductors, which makes such a massive cable more economical to build. 

Another major advance involves how these subsea cables are powered. At the moment, the capacity of the subsea cable is limited by the amount of electricity that can be delivered from shore to a series of repeaters (which boost the signal along the length of the cable) placed about every 50 miles along the cable. Consider, for instance, a transatlantic cable that runs between Europe and the United States at over 7,000 kilometers in length, and all those repeaters getting their electricity through the cable from shore. This makes the cable a very long power cord.

 To solve this challenge, engineers are working on buoys that can deliver power to the repeaters from the middle of the ocean. We’re exploring more sustainable ways to do this, harnessing a combination of wave energy convertors and solar panels. This unique solution will allow us to advance technology innovation as we evolve from .5 petabits per second to 5 petabits per second — that’s 10 times the capacity.

We also continue to innovate and evaluate how and where we place the cables. For instance, we built a predictive modeling tool, the Atlantis model, to help us forecast where subsea cable routes need to be built to ensure network availability during unexpected events.

The Atlantis model helps predict where to place subsea cables.

Our impact is possible thanks in large part to our partnership approach. For example, our Echo and Bifrost cables rely on local consortium partners, including Keppel, Telin, and XL Axiata. Together, we are working to increase overall transpacific capacity by 70 percent. Scaling subsea infrastructure is an important part of our overall approach to building global connectivity systems that will help connect many more people to the internet in the coming years. 

Using robotics for faster fiber deployment

While subsea cables are part of the backbone of the global internet, once a subsea cable reaches shore, the next step is to deliver bandwidth to communities. But current methods of deploying fiber are labor-intensive and costly. As a result, fiber installation has been a bottleneck to deploying more fiber and creating the type of abundance needed to give everyone, regardless of income level, unfettered access to the internet.   

Since each strand of fiber costs pennies per meter, while installing the fiber costs between tens of dollars and hundreds of dollars per meter, we wondered whether we could bring down the cost of installing fiber cable.  

“To answer this question, we first thought of medium-voltage power lines, the familiar three wires you see at the top of a utility pole,” says Karthik Yogeeswaran, a wireless systems engineer at Facebook. “In most of the world, medium-voltage power lines pass down almost every street. If we could find a way to add fiber to those power lines, we would have a solution that could be applied globally.”

Our solution is Bombyx, an aerial fiber deployment robot that makes it faster and cheaper to deploy fiber. Latin for silkworm, Bombyx is our attempt to make the single biggest drop in the cost of terrestrial fiber deployment by combining innovations in the fields of robotics and fiber-optic cable design to increase the amount of terrestrial fiber on land — without the expense of trenching to lay fiber underground.

Since starting work on Bombyx, we have shed 4.5 kg from the weight of the robot, compressed the time it takes for Bombyx to cross a power line from 17 minutes to under 4 minutes, and improved the stabilization system that enables the robot to pass over obstacles. 

We are also now working on getting the robot from operating semiautonomously to fully autonomously when going over an obstacle. With our current semiautonomous system, operators supervise and direct the robot’s movements as it crosses obstacles. As we move to full autonomy, technicians will be able to simply load Bombyx onto the line and then allow the robot to plot a course past obstacles and navigate itself along the line.  

Our work on Bombyx was inspired by helical fiber-optic wrapping techniques pioneered in the 1980s, but those methods required interrupting power to customers during installation. We realized that in order to install fiber without cutting off homes and businesses, we would also need this wrapping machine to cross obstacles in its route without human assistance.

First, however, we had to address some pressing fiber cable design challenges. For instance, when you wrap fiber around a power line, you need to carry the full span of fiber you intend to deploy. A kilometer of normal aerial fiber weighs approximately 113 kg, and even the special cable used in the older helical wrap systems weighed roughly 36 kg. Combined with a robot to deploy the fiber, it would be too heavy for power lines, which are typically very thin and can only support so much weight. Medium voltage conductors also get really hot, so we needed a fiber cable that could withstand potential stretching and melting. 

 To address these design challenges, we employed a few strategies. First, we used Kevlar braiding to make the cable strong, while remaining small and flexible. Next, we addressed the size and weight challenge and reduced  the fiber count from 96 to 24. Thanks to newer technologies, a single fiber can serve up to 1,000 homes, so 24 fibers would be able to serve all the homes and businesses into which each power line feeder passes. Finally, we worked with top material suppliers to develop a jacket for the fiber so it could survive the high temperatures found on power lines and any potential arcing damage in high voltage.

Designing a robot to crawl along power lines and to clear obstacles was our next big task. Bombyx uses advanced motion techniques to balance itself and to flip over as it moves over obstacles and wraps fiber around power lines. 

Bombyx wraps fiber around existing power lines, clearing obstacles and flipping as it needs to along its route

Each robot will eventually be capable of installing over a kilometer of fiber and passing dozens of intervening obstacles autonomously in approximately an hour and a half. While it is still early days, engineers are optimistic about its potential impact.

Utility companies are also very interested in Bombyx, as they increasingly need fiber broadband to modernize their grid operations and are being called on to help bridge the digital divide. “Bombyx offers utilities a tool to meet their grid modernization needs and support broadband into their most rural areas at a lower cost to utility rate payers,” says Joshua Broder, CEO of Tilson, a network consulting, design, build, and development company. 

Terragraph: Fiber connections through the air 

Once we can increase the amount of fiber provided to communities, we can tackle the last step and get fiber the final distance into people’s homes and businesses. This “last mile” connectivity has been one of the most complicated challenges to solve.

Facebook Connectivity developed a technology called Terragraph that bridges the last mile over the air and gets multi-gigabit speeds to buildings wirelessly at a fraction of the cost of traditional approaches. Terragraph is already making a dramatic impact in people’s lives in Anchorage, Alaska, and Perth, Australia, and we are on our way to scaling Terragraph much more widely.

Terragraph uses transmitters on street fixtures and rooftops to create a distributed network for high-speed reliable connectivity in homes and businesses. Terragraph is faster to deploy than trenched fiber because it builds on existing fiber points of presence and extends the capacity wirelessly, through nodes mounted on existing street fixtures such as lamp posts and traffic lights. 

Terragraph nodes are attached to lampposts and rooftops in a multinode network, creating a resilient mesh that can reroute the signal if necessary so that capacity will not be cut to homes and businesses in case of an obstruction, such as a building scaffold

What started in 2015 as an early-stage technology is now being scaled to market through our partner ecosystem of OEMs and service providers around the world. We license Terragraph for free to OEMs, and five partners have already announced that they have Terragraph-enabled hardware products available. To date, these OEM partners have shipped more than 30,000 Terragraph units to more than 100 service providers and system integrators around the world. 

We are already seeing the impact of Terragraph in two recent commercial deployments — Anchorage, Alaska, and Perth, Australia. In partnership with Cambium Networks, Alaska Communications is providing 1 gigabit download speeds and 100 Mbps upload speeds to over 6,500 homes in Anchorage, with plans to expand to more neighborhoods in Anchorage, Fairbanks, Juneau, and the Kenai Peninsula over the coming years. You can read and see how Alaskans’ lives are being changed by faster, more reliable internet here.

Perth, Australia, one of the most isolated cities in the world, is another community where the impact of Terragraph has been profound. “In 2019, Perth was reported as having the second slowest internet speeds of all Australian capital cities,” says Stephen Cornish, CEO of Pentanet.  

Pentanet is leveraging Cambium Networks’ 60 GHz cnWave equipment, enabled by Terragraph, to bring high-speed internet to people in Perth for whom affordable, reliable high-speed connectivity is more important than ever. “The metaverse and gaming are transforming the internet, and gigabit speeds are needed,” adds Cornish. 

What’s next?

We will continue to evolve all of our connectivity technologies. We’ll begin trials shortly to test the floating buoys that will power our subsea cables in the middle of the ocean. On land, soon we’ll start trials of Bombyx with utilities. We will also continue to partner closely with OEMs to scale Terragraph to many other markets around the world.

We are proud to reach our milestone of bringing high-speed reliable internet to more than 300 million people — but the work doesn’t stop there. Connecting a billion more people will require many different approaches, and we will continue to build innovative solutions to help the industry close the digital divide. 

“People are eager for even better ways to connect than what exists today, and there is still a lot to do to improve that digital experience,” says Mike Schroepfer, Facebook’s CTO. “A set of new virtual spaces — which many people are already calling the metaverse — will help answer this challenge. It will enable the next generation of online social experiences that are more engaging and immersive than we ever thought imaginable.”

Connecting people in these ways means we need to increase access to a faster, more reliable, and affordable internet for everyone. We believe this work is fundamental for creating greater equity where everyone can benefit from the economic, educational, and social benefits of a digitally connected world.