These Toaster-Oven-Size Radios Will Help Bring 5G to Life

Within a few years, 5G networks could turbocharge your smartphone. But can they pass the tests cooked up by engineers at an office park in New Jersey?

Live-streaming a virtual-reality broadcast. Downloading a 90-minute high-definition TV show to your smartphone in less than three seconds. Sending instant updates on road conditions to self-driving vehicles. These scenarios are impossible or prohibitively expensive on current cellular networks, but they should be feasible with the next generation of wireless connectivity, 5G. It promises to be 10 to 20 times faster than today’s cell-phone networks.

That’s because 5G will operate in a high-frequency portion of the radio spectrum, known as millimeter wave. It has a lot of available bandwidth and should make it possible for wireless devices to process data with minimal delays. But since its wavelengths are much shorter, it is more easily obstructed. And because it has never been used for consumer mobile services, carriers are still learning how 5G signals will behave in different types of terrain and weather. “We need to look at how the signals are affected by things like snow, rain, sleet, hail, maple trees, oak trees, and spruce trees, because each of those will be different,” says AT&T research engineer Bob Bennett.

The problem: most 5G measurement equipment is so expensive, fragile, and bulky that it can be deployed outdoors for only a few hours at a time. ­Bennett and colleagues say that far more real-world data is needed to properly develop the technology, so they have created weatherproof radios the size of toaster ovens and installed them across AT&T’s 260-acre campus in Middletown, New Jersey, which was once part of Bell Labs.

Since deploying the radios last September, the engineers have seen how tree leaves, heavy rain, and truck traffic all obstruct millimeter-­wave signals to some extent. AT&T plans to share the information with the rest of the telecom industry to aid in the design of 5G technical specifications, base stations, modems, smartphone chips, and more. The new technology won’t be commercially widespread until after 2020, but these small, homemade radios are a crucial step toward making it real.

Research engineers hacked together these testing devices as part of their effort to see how 5G networks will perform in wooded areas and in inclement weather.
AT&T redesigned its measurement equipment to include 30 to 40 percent fewer components. Some parts were custom-built. Some were produced in-house.
The components are housed in weatherproof boxes that are small enough to fit on telephone poles.
The roof of the main building on the Middletown campus is home to five 5G measurement systems, as well as other radios, weather stations, and solar panels.
AT&T is also building an anechoic chamber to see how building materials, such as glass or drywall, may affect millimeter-wave signals. The chamber will be completely covered with a blue foam material that absorbs radio waves.
Engineers will place objects like potted trees and cross-sections of house walls on this large turntable to measure their effects on millimeter-wave signals at different angles.
Later this year, AT&T plans to install additional 5G measurement systems outdoors, and may use one of its testing vans to conduct tests outside the Middletown campus. The van’s mast can extend up to 50 feet.