30 November 2017 | By IEEE Spectrum|
A hulking orange helicopter named Annie hoists a gleaming metal tower into the sky on the outskirts of Kotzebue, a small Alaskan city just north of the Arctic Circle. Engines roaring, Annie pauses to steady its load, which had begun to sway below, and veers off toward a bald mountaintop.
On the mountain, at a rocky site called Igichuk, a work crew has just finished setting up the tower’s base, dropped off earlier by Annie. Now, they’re focused on executing the most delicate delivery of the day, one of many difficult steps required to sink a single new telecommunications tower into the vast, roadless Alaskan tundra.
When Annie arrives, the pilot carefully dangles the new section of tower above its base. Below, four crew members stand ready to guide it into position, strapped into harnesses with their feet braced against the base’s highest rung. Once the new section of tower is close enough, each crew member grabs a steel rope looped through one of its lowest joints and gently nudges the tower so that it is centered directly over the base. Within minutes, the section is lined up, its four metal feet perfectly aligned with the base’s corners.
The crew works quickly to insert a single bolt into each leg; they’ll go back and add more later. When they give the sign, the pilot releases the tower from Annie’s grasp, and pulls away. The tower stands, now the highest point across the tundra, and sparkles in the midday sun. Once active, it will relay data north to several hundred miners at Red Dog, the world’s largest zinc mine, and back to a tower in Kotzebue, a city of 3,245 built on a thin lip of spongy land that bows out into the Chukchi Sea along the isolated western rim of Alaska.
Here on the edge of the U.S. Arctic, Internet connectivity is a slow—and expensive—proposition. Eighty-one percent [PDF] of rural residents in Alaska do not have broadband Internet, defined by the U.S. Federal Communications Commission (FCC) as providing a minimum download speed of 25 megabits per second. People in Kotzebue have long relied on satellite connections for Internet service at speeds comparable to those of dial-up. At the beginning of the year, their average download speed was just 2 Mb/s.
The Igichuk tower is one of the final pieces of one of the most ambitious telecommunications projects in the rural United States. Built by General Communication Inc. (GCI) and known as TERRA, it was completed this past October, after US $300 million of investment and six years of construction, when engineers installed its final microwave repeater. The network uses a combination of repeater data links and fiber optics to form a giant, 5,000-kilometer ring around southwest Alaska—a sparsely populated region with few paved roads and wilderness areas larger than West Virginia.
With TERRA, Kotzebue residents now pay $59.99 per month for an Internet plan with download speeds of 3 Mb/s, which is not even fast enough to stream a high-definition movie. To be able to do that, they would need to pay at least $149.99 per month for 6 Mb/s. Compare that with New York City, where residents pay an average of $55 per month for 25 Mb/s.
So was it worth $300 million to bring slightly better Internet to approximately 45,000 people in 84 rural villages spread out over an area roughly the size of Germany? For GCI, it was a strategic move. The project was completed as more customers began to watch more content online. Large clients such as hospitals and schools in rural communities also needed better access to the outside world. Partly thanks to TERRA, the company welcomed $12 million in new revenue for Internet service in the first three quarters of 2017, while losing $8 million from its cable-TV division.
Connecting remote areas has also become a hot topic among tech-industry titans, which are all developing competing last-mile solutions, such as Facebook’s Internet delivery drone and Alphabet’s high-altitude balloons. Some analysts downplay those projects as flashy experiments. Other experts have argued that the world must keep building conventional networks to serve hard-to-reach areas, just in case those blue-sky ideas don’t pan out.
TERRA relies primarily on 109 microwave towers, a classic technology that can still be deployed faster and more cheaply than fiber-optic cables in most of rural Alaska. But the project nevertheless took GCI a very long time and a lot of money to complete. It shows what a challenge it can be to build and maintain a communications network in one of the most remote areas in the world—even when you are using the most tried-and-true technology available.
To deliver nationwide telephone service, AT&T and other telecommunications companies built vast microwave networks across the United States in the 1950s. They put up thousands of towers and repeaters to provide long-haul links between communities.
Over the past couple of decades, those microwave networks have been steadily replaced by fiber optics, which provide much greater bandwidth and therefore far higher data speeds. So now, the United States has some 182,000 km of long-haul fiber-optic cables, and microwave cell towers are increasingly relegated to shepherding data between customers and the nearest cable.
However, burying fiber-optic cables is extremely difficult in Alaska, a state divided by three major mountain ranges and half a dozen minor ones, where permafrost covers 85 percent of the land, and where undersea cables are occasionally sliced by fishing trawls or sea ice that forms along the coast each winter.
TERRA does include about 700 km of fiber, most of it buried around Anchorage and along Alaska’s limited road system. For one stretch, a diver even laid fiber across the bottom of the still-frozen Kvichak River, in an area frequented by brown bears.
But TERRA relies on microwaves in a way that hardly any other new large-scale networks have since the 1990s. And because there is no road system throughout much of Alaska, each of those microwave towers had to be flown or barged in. Some were installed in villages, and 23 were hoisted to mountaintop sites like Igichuk by a small fleet of helicopters.
These towers, all 109 of them, poke up every 15 to 65 km in the Alaskan bush. Extending outward from this main ring, several spurs connect half a dozen villages each. “Using microwaves, we can kind of look at it as island hopping, where we hop from island to island to provide service and get over larger stretches of wilderness,” says Patrick Goodyear, senior engineer for TERRA at GCI. All told, the ring and the spurs connect dozens of tiny villages, among them the famous gold-rush town of Nome, and also Shaktoolik (population 258) and Shageluk (population 81).
Annie and the other Aircranes, as they’re known, have been a key technology used by GCI and STG—the contractor that oversaw many TERRA tower installations—to reach such remote and offbeat places. Annie is a beast, burning more than 2,000 liters of fuel per hour and capable of carrying 11,000 kilograms on its hook. Manufactured by Erickson, only 20 Aircranes like it exist in the world.
During its first season of construction, STG used a gin pole, a common way to erect a telecom tower in sections without using a helicopter, at the most remote sites. But it took crews two to three weeks to install a tower. “With an Aircrane coming in, we can stack a tower as fast as it can bring the equipment in,” says Brennan Walsh, president of STG.
The real problem at those remote sites is power: Most of them are far away from the electrical grid. Rebecca Markley, GCI’s director for rural initiatives, says the company considered installing solar arrays to power those towers, but soon found the arrays would take up too much room at the sites, some of which are barely big enough for a helicopter to land.
Back at Igichuk, Annie dropped off two diesel-fueled generators that will keep the new site running around the clock. Later, a smaller helicopter equipped with a giant fuel bladder would make 30 round trips to fill a 34,000-liter tank with fuel. That’s enough diesel to run the tower for 15 months.
Specifying such a long run time is typical of GCI’s design philosophy for the TERRA project, in which each site has been built with multiple layers of hardware redundancy along with special adaptations to help it weather extreme conditions. For example, each mountaintop tower has a backup generator, along with a rack of 48 lead-acid batteries that can keep the tower operating for at least two days, should the backup generator also fail.
That kind of fault-tolerant approach to system design has already paid off. One November, at a mountaintop site called Cone Shoulder, a ground fault caused both generators to fail in the middle of a blizzard. The site ran on batteries until technicians could repair it, three days later.
The HVAC systems at each mountaintop site also have twice as many fans and vents as they need to cool the communications modules. And the router box, which manages radio traffic and controls the HVAC system, contains multiple modules that can handle all the necessary functions for the radios and HVAC control, just in case one module fails.
Because many of the towers are built on permafrost, they could tilt perilously should the ground ever thaw. To prevent this, GCI employed a technique also used for the Trans-Alaska Pipeline and installed passive refrigeration devices called thermosyphons in the pilings on which the towers rest. Thermosyphons are partially buried, with a portion sticking up into the air. They are tubes filled with gas that cools above ground and condenses into a liquid, which then evaporates. That evaporation sucks heat out of the ground, making sure it stays frozen.
Ultimately, one of TERRA’s greatest strengths comes from its shape. Circles or rings create extra resiliency within a network: If one site does go down, all the traffic can be immediately routed in the opposite direction, taking the long way around the ring but ultimately getting where it needs to go.
So far, TERRA’s rigorously fault-tolerant hardware has survived everything the forbidding Alaskan wild could throw at it. But the software? That’s another story.
Software has made networks more flexible and responsive—and TERRA is no exception. In the network, basic characteristics of the microwave channels are configured by software scripts. For example, software defines the frequency and amplitude of the carrier wave on which a signal is transmitted. The network handles traffic based on priority levels assigned through software. “Software controls just about everything,” Goodyear says.
Unfortunately, that also means faulty software can knock out a site or disrupt multiple portions of the network. A few years ago, while technicians were trying to upgrade one stretch of towers, a software bug caused the radios to spontaneously reset and pushed GCI nine months behind schedule.
These problems notwithstanding, software is at the very heart of the TERRA network’s ability to function in the face of the Arctic’s environmental and climatic extremes. Thanks to software, GCI can remotely route all traffic through one tower if another one malfunctions. And software helps the network respond to weather, altering signals when there’s more fog or rain, in ways that minimize signal attenuation.
At GCI’s office in Anchorage, senior engineer Goodyear pulls up a photo of a microwave tower high in the Askinuk Mountains on the western coast of Alaska. The bottom half is buried in 2.5 meters of snow. “This is pretty typical for this site in the early spring,” he says. He flips to another photo [see below: “Cold Call,” bottom photo] that shows the top half of the same tower completely iced over from chilly coastal winds that whip up moisture from the Bering Sea.
Snow and ice absorb and reflect radio waves, impeding an antenna’s ability to receive and transmit signals. Goodyear estimates GCI poured $2 million into combating that problem at the Askinuk Mountains site in its first two years. He points to the small triangles above each antenna in the second photo; they’re basically metal hats meant to keep snow and ice from accumulating.
Crews had also installed long metal plates to shield the tower’s waveguides from falling ice. Microwaves travel through waveguides—which are hollow metal tubes—when they are moving between amplifiers and antennas, for example. But in frigid climates, moisture can accumulate inside them and cause them to freeze up, so at particularly vulnerable TERRA sites a special dehydrator pushes air through the waveguides to keep the moisture out.
Despite all of these efforts, one antenna is still missing from the tower in the photo, and the waveguide that runs to it sticks out awkwardly into the cold air. Ice had built up, warmed in the sun, slid down the tower, and popped the antenna right off.
Through software, GCI was able to remotely reroute traffic from the disabled antenna to go through two antennas placed higher up on the tower, to keep the site running. Since then, Goodyear’s team has slashed the height of that tower to limit its exposure to icy gales. So far, that fix seems to be working.
GCI engineers have also made hardware adjustments to improve signal strength across the network when a site is working but not as well as it could. For example, near a coastal town called Quinhagak (population 669), a tower sits high up on the shoulder of a mountain, with barely enough room for a helicopter to land next to it. To save space, the GCI crew initially installed a shorter tower with 1.8-meter antennas.
But a reflection point on nearby Kuskokwim Bay soon began to impede service to the next tower. Occasionally, when the tide was just the right height, a few stray microwaves would bounce off the bay and right into that tower’s antenna. But they arrived later than the microwaves that traveled straight over, causing the two signals to destructively interfere with each other.
So now GCI is upgrading that site to 3-meter antennas, which will not “see” the reflection point from the same angle as the smaller antennas. If all goes well, this geometry will cut back on the reflected microwaves.
To build anything in Alaska requires a certain amount of fortitude.Looking back, GCI’s Markley says, “there have been lots of times where we were thinking, ‘Are we actually going to be able to do this?’ ”
No other company had ever thought it economically feasible to deliver terrestrial Internet to this remote part of Alaska. If TERRA had been built in the contiguous United States, it would stretch from Washington, D.C. to Seattle. But it will serve about as many customers as live in Twin Falls, a small city in Idaho.
TERRA was made possible by a patchwork of federal grants, loans, and subsidies. Heather Handyside, GCI’s communications director, acknowledges TERRA wouldn’t have been built without the American Recovery and Reinvestment Act, signed into law in 2009. Through it, the federal government contributed $82 million in grants and loans to the $300 million project. GCI also secured about $35 million in federally supported loans through the New Markets Tax Credit program, and received another $6 million federal grant for the project.
On top of all that, GCI collects more federal money through the federal government’s E-Rate Program, which subsidizes telecommunications costs for schools and libraries. The company says TERRA provides a path for rural Alaskans to access distance learning, take advantage of telemedicine, and diversify their economy by telecommuting or selling handicrafts on retail sites like Etsy.
Even with all that support, the rates that TERRA customers pay remain much higher than elsewhere in the United States. The most expensive GCI plan for Kotzebue costs $300 a month for speeds that are about 8 percent those of the least expensive Anchorage plan, which is $65 a month. GCI points out that speed is only part of the picture: TERRA has reduced latency from 550 to 25 milliseconds for rural customers, making it much easier to hold video conferences. (Several Alaska Native corporations and organizations contacted for this story, including NANA Regional Corp., which serves Kotzebue, declined to comment on TERRA or GCI’s rates.)
After years of neglect by telecommunications companies, rural Alaska is now attracting interest. GCI is facing competition in at least a small slice of TERRA’s service area. A company called Quintillion recently installed a subsea fiber-optic cable to provide broadband to villages along the northwest coast of Alaska, the first phase of a cable that will stretch from Tokyo to London.
That’s good news for Alaskan customers, and bad timing for GCI. The final repeater in the TERRA network was switched on in October, at a site coincidentally labeled on the TERRA map as Final Repeater for its proximity to Final Mountain.
Now in place, the TERRA towers have an expected life-span of 50 to 60 years. During that time, several new generations of wireless technology will come along, requiring GCI to upgrade its equipment. Already, crews have begun to replace generators at the earliest sites, which have reached the end of their five-year life-span.
With TERRA up and running, GCI’s investment has finally begun to pay off, and many Alaskans are sure to benefit from their access to it. Before long, they could start to demand even more data and faster speeds. But given TERRA’s constraints, GCI may struggle to deliver it in a timely manner and at an affordable price.
Meanwhile, Quintillion or another competitor could take on the herculean task of burying more fiber across Alaska—that is, if Facebook and Alphabet don’t figure out how to offer broadband coverage cheaply by balloon or drone.
GCI does sell capacity on TERRA to other telecom companies, which should further expand access for residents, but competitors say the price GCI charges is too high and accuse it of holding a monopoly over Internet service throughout much of rural Alaska. Several competitors, including a coalition of rural telecom providers, have complained to the FCC about GCI’s wholesale pricing.
Given all of this, there would seem to be ample room for a clever company to devise a way to bring faster, cheaper connectivity to the Far North. Developing it would certainly not be for the faint of heart, and it may always be an economically risky proposition. But it could also represent a true breakthrough, reaching the dozens of Alaskan villages that still remain without terrestrial Internet of any kind.