Satellite communications networks require three main components to work. One is the spacecraft in orbit, the second is the user terminal — the antenna on a home, business, ship, plane or other location.
The third is the ground network, a collection of earth stations connected to the internet by fiber optic cable. These locations, often called gateways, have large antennas aimed at the satellite and serve as the intermediary between the user and the internet.
Traditionally, gateway antennas are quite large — 7 meters or more in diameter. They’re often accompanied by a secure, air-conditioned room or shelter full of servers and other electronics, power supplies, a backup generator and other infrastructure. A nationwide network like those Viasat manages might have dozens of gateways, often in remote locations, to serve one satellite, and the cost to build and operate this ground segment can be significant.
Much of this, however, is changing. Viasat’s goal to continually push down the cost of bandwidth while also improving our overall performance and capacity depends in large part on the satellite advances we’ve made.
But the ground segment is every bit as important.
Just as mobile network capacity improves with more cellular towers, higher capacity satellites need more antennas on the ground. We’ve changed the traditional model described above a great deal with our newest satellite, ViaSat-2, drastically reducing the size and cost of each ground station while increasing the number and improving the performance.
In fact, we made such significant changes to these satellite gateways that we gave them a new name: Satellite Access Node, or “SAN.”
Smaller is better
One big reason many satellite networks have such large antennas on the ground is to accommodate high-powered signals able to cut through weather. Rain and clouds can hamper performance, and when you only have a small number of gateways, you want to ensure they’re all working at optimum performance levels.
To get the breakthrough increases in capacity from our new satellites, we need to use more SANs and distribute them around a geographic area. As a side benefit, when bad weather affects the performance of one or two of them, it isn’t such a big deal. Even if one of them goes down for some reason, the multiple redundancy you get from having many more SANs easily makes up for it. So adding more sites means you can get the performance required out of much smaller antennas.
Another way Viasat reduces the size of each SAN is by relocating many of the processor functions to a nearby data center — essentially a private cloud. Rather than having banks of servers at the gateway, most of that is virtualized using open computer platforms. That eliminates a lot of the space required for the servers and all the infrastructure needed to power and cool them, as well as backup generators and redundant fiber lines.
The importance of all this can’t be overstated: By driving down the cost of the ground system while improving it at the same time, we’re able to provide better service and increase capacity over the network. When our next generation of satellites, ViaSat-3, are launched, they will be connected to an even more sophisticated ground network with a great many more SANs.
Viasat's growing fiber network
Although Viasat is primarily a satellite communications company, our need to connect our ground network to a fiber backbone means we’re on our way toward operating a large fiber network. Since most companies that own fiber lines have additional capacity, we’re able to purchase what we need without having to lay fiber ourselves.
There’s also a fair amount of “dark fiber” out there, which refers to unlit strands of glass on fiber optic cables. In many instances, the owner of that fiber might sell us the rights to use these unlit strands, and we’re responsible for lighting them up.
Another way we can streamline our ground network is by direct peering with some of the larger players. We might, for example, establish a direct peering relationship with a video streaming service or content provider so that our network traffic has a more direct link to these services.
Even with fiber’s ability to handle an extraordinary amount of data, any additional efficiencies we can realize — such as direct peering — can shave precious milliseconds off the time it takes to deliver packets of information, all of which results in improved user experience.
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